2.0 ALTERNATIVES

2.1 INTRODUCTION

This chapter presents the three alternatives (and three variations) still under consideration and the alternative evaluation process. The alternatives presented in this chapter are the result of an extensive public and agency process, combined with environmental and technical analysis. Elements of the public and agency process included several scoping meetings, numerous public meetings, neighborhood group meetings, one-on-one meetings, media outreach, project newsletters, a Web site, a project office, and various advisory committees.

From the public and agency scoping meetings, more than 80 alternatives for improvements were identified. A three-step evaluation process was used to progressively eliminate alternatives from further consideration. From this evaluation process, the Long-Term Vision for South I-25 and US 85 Through 2020 and Beyond was developed to meet the project objectives and community vision. Vision elements likely to be constructed over the next 20 years are presented and comparably evaluated in this Final Environmental Impact Statement (FEIS). This FEIS presents the evaluation of the No-Action Alternative, Preferred Alternative, and Other Alternative. The Other Alternative expands and modifies the elements included in the Preferred Alternative. The Preferred Alternative and Other Alternative were developed based on comments made during the Draft EIS (DEIS) formal comment period and through additional analysis. One of these alternatives, or an alternative developed from a combination of the three, will likely be the Selected Alternative presented in the ROD.

After the initial three-step alternative evaluation process that developed the Long-Term Vision Through 2020 and Beyond was completed, the I-25 project limits were extended from Lincoln Avenue to C-470. This extension was necessary to be compatible with the Southeast Corridor improvements and to provide lane continuity along I-25. A notice of intent to extend the corridor limits was published in the Federal Register on November 9, 1999. The Long-Term Vision and the alternatives evaluated in this FEIS reflect the project limit extension.

Sections of this chapter highlight the alternative evaluation process. The first section is a discussion of the public/agency involvement process that was completed throughout the EIS. The second section is an overview of the alternative evaluation process that was followed throughout the FEIS. The third section defines the No-Action Alternative, Preferred Alternative, Other Alternative, and Alternative Variations. The fourth section discusses the Long-Term Vision, which provides an overview of the community’s vision for both corridors through 2020 and beyond. The fifth section provides additional detail of the evaluation process that developed the Long-Term Vision and the alternatives that were eliminated.

The Federal Highway Administration (FHWA) and the Colorado Department of Transportation (CDOT) have chosen the Preferred Alternative because it best meets the local communities needs and desires, fulfills the project objectives, and provides flexibility in future transportation needs.

2.2 PUBLIC/AGENCY INVOLVEMENT PROCESS

An extensive public/agency involvement process has been ongoing since the project began in October 1998. This process involves meeting with various community groups, agencies, developers, landowners, special interest groups, and the general public. Four committees/teams representing various interest groups met once or twice a month to discuss the project. Newsletters, a Web site, project hotline, and project office are used to enhance community outreach. The committee/teams that have been involved with this EIS process and a brief discussion of their responsibilities and membership are provided.

2.2.1 Issues Team

The Issues Team consists of representatives from the affected interests, community groups, special interest groups, and the general public. The Issues Team provides input into the EIS process and assesses and reviews recommendations. Their roles and responsibilities include the following activities:

• Provide insight into the planning process and stakeholders’ concerns
• Ensure all ideas and concerns are considered throughout the process
• Disseminate project information to neighbors, community groups, and affected interests

2.2.2 Technical Committee

The Technical Committee is made up of agency staff including FHWA, CDOT, Federal Transit Administration (FTA), Federal Railroad Administration (FRA), Douglas County, Town of Castle Rock, Denver Regional Council of Governments (DRCOG), Regional Transportation District (RTD), Public Utilities Commission (PUC), City of Lone Tree, and Colorado Division of Wildlife (CDOW). Their roles and responsibilities include the following activities:

• Technical review of project reports
• Technical support and insight on agency issues and regulations
• Coordination and communication with their respective agency staff and/or elected officials
• Assistance in developing, screening, and evaluating alternatives

2.2.3 Project Management Team

The Project Management Team is an advisory group made up of CDOT, DRCOG, Douglas County, Town of Castle Rock, and the consultant team. The Project Management Team acts in an advisory capacity. Their roles and responsibility include the following activities:

• Provide guidance, insights, and input to the consulting team throughout the EIS process
• Review project documents
• Communicate project status, issues, and recommendations to their agency

2.2.4 Ecological Resources Technical Advisory Committee

The Ecological Resources Technical Advisory Committee (ERTAC) is made up of agencies having interests or responsibilities with the ecology within the study area. ERTAC consists of representatives from CDOT, CDOW, Douglas County, Chatfield Basin Conservation Network, Shea Homes, Intermountain Rural Electric Association (IREA), Chatfield State Parks, Chatfield Basin Conservation Network, and the Cherokee Ranch Foundation. Their roles and responsibilities include the following activities:

• Provide support and guidance on ecological issues
• Perform technical review of project reports

These four teams are part of the ongoing public/agency involvement process, and have been involved throughout the alternative evaluation process. In addition to the above-mentioned formal committees/teams, 12 public open houses and 8 community meetings have been conducted throughout the alternative evaluation process. CDOT met periodically with a Douglas County trails group to obtain insight on the proposed bicycle/pedestrian facilities along US 85 as well.

2.3 ALTERNATIVE EVALUATION PROCESS OVERVIEW

An evaluation process was used to evaluate more than 80 different alternatives for I-25 and US 85 and to reduce the number of alternatives to those that are most reasonable and best meet project objectives. The result of the evaluation process, combined with community input, is the Long-Term Vision for South I-25 and US 85 Through 2020 and Beyond. Based on financial constraints and demand, not all of the improvements can be constructed before 2020, which is the planning period for this study.

The South I-25 Corridor and US 85 Corridor Alternative Evaluation Process was developed with input from the public, the Issues Team, Technical Committee, Project Management Team, and ERTAC. The evaluation process applies progressively more finite criteria to the alternatives through three levels of evaluation. The evaluation process and Long-Term Vision analysis are displayed on Figure 2.1. As shown on Figure 2.1, the process uses a systematic approach to develop the best alternatives for each corridor.

To develop the Long-Term Vision, three evaluation levels were used: 1. Eliminate Unrealistic Alternatives 2. Evaluation of Alternatives by Mode and Corridor, and 3. Evaluation of Packages by Corridor. Alternatives were analyzed and compared at each level based on criteria from five categories: mobility, safety, environmental, implementation, and community values. These categories and respective criteria were developed from the project purpose and need, project objectives, public input, and environmental regulations. Table 2.1 outlines the criteria used for each level of evaluation. For additional information on the alternative evaluation process, please refer to Section 2.12: Alternatives Eliminated From Consideration and the South I-25 Corridor and US 85 EIS Alternatives Evaluation Process, March 2000.

After the Long-Term Vision was finalized, the elements that best addressed the purpose and need and could realistically be funded within the next 20 years were carried into the full DEIS alternative evaluation for comparative analysis. The alternatives fully evaluated in the DEIS included the following:

I-25 Corridor Alternatives:

• Alternative 1: No-Action
• Alternative 2: Mainline Widening (Additional General-Purpose Lanes)
• Alternative 3: Mainline Widening (Additional General-Purpose Lanes), Interchange Improvements, and Frontage Road

US 85 Corridor Alternatives:

• Alternative A: No-Action
• Alternative B: Mainline Widening (Additional General-Purpose Lanes) and Reconstruction

The FEIS alternatives were developed based on public and agency comments on the DEIS alternatives and additional analysis. The FEIS alternatives being evaluated accommodate the Long-Term Vision elements and do not preclude any of the identified improvements. The FEIS alternatives being evaluated in this document include:

• No-Action Alternative
• Preferred Alternative
• Other Alternative

Characteristics of each of the three alternatives evaluated in this FEIS are discussed in the following sections. Two build alternatives are being fully evaluated in this FEIS to allow for the flexibility of selecting different improvement options based on the identified funding. Funding has been identified for the improvements included in the Preferred Alternative. However, funding has not yet been identified for all of the improvements included in the Other Alternative. These improvements are being evaluated in this FEIS so that if funding is identified, with the appropriate amendments, they may be constructed.

2.4 NO-ACTION ALTERNATIVE

The No-Action Alternative represents the conditions if improvements are not recommended as a result of this study. This Alternative consists of no major improvements other than the Early-Action projects that have already been committed and the construction of the Douglas Lane Interchange. These projects are independent projects and accepted as part of the No-Action Alternative. The No-Action Alternative also includes minor safety and maintenance improvements along I-25 and US 85 (e.g., pothole repair and re-striping). Early-Action projects and the Douglas Lane Interchange included in this alternative include the following activities:

• Climbing Lanes, Phase I. This project provides one additional lane in each direction along I-25 between Lincoln Avenue and Castle Pines Parkway designated (but not restricted) as climbing lanes for slow-moving vehicles. The I-25 configuration after the completion of this project is six lanes between Lincoln Avenue and Castle Pines Parkway. This project was completed in October 2000.
• Climbing Lanes, Phase II. This project extends the Climbing Lanes Phase I project to Meadows/Founders Parkway. The I-25 configuration after the completion of this project is six lanes between Castle Pines Parkway and Meadows/Founders Parkway. This project is currently under construction and is scheduled to be completed in September 2002.
• Meadows/Founders Parkway Interchange. This project improved the existing diamond interchange deficiencies by constructing a partial cloverleaf interchange. This project was completed 1999.
• Wolfensberger Road. This project improves the existing I-25 interchange deficiencies by removing and replacing the south half of the Wolfensberger Road Bridge over I-25 and Plum Creek. This project is scheduled to begin construction in Fall 2001 and be completed in Fall 2002.
• US 85/I-25 Interchange. This project removes the existing US 85/I-25 Interchange ramps and reroutes traffic through the improved Meadows/Founders Parkway/I-25 Interchange. An overpass is constructed at the existing interchange location to connect the east side of Castle Rock to the west side. This project is scheduled to begin construction in Summer 2001 and be completed in Fall 2002.
• 5th Street Overpass. This project improves the local Castle Rock transportation network by providing an overpass from 5th Street on the east side of I-25 to Park Street on the west side of I-25. This project began construction in October 2000.
• US 85 and Titan Road Grade-Separated Intersection. This project improves existing safety deficiencies of the railroad crossings by constructing a grade-separated intersection at US 85 and Titan Road and by providing grade separations with Titan Road and the Burlington Northern Santa Fe Railroad and Union Pacific Railroad. With the proposed design, traffic crossing the existing Union Pacific Railroad tracks at the existing at-grade crossing will be limited to local business access. Construction is scheduled to begin in October 2001.
• Douglas Lane Interchange. This project provides a new interchange along I-25 at Douglas Lane, approximately 1,450 meters (4,750 feet) south of Plum Creek Parkway. The interchange design is a single-point urban interchange. Funding for the Douglas Lane Interchange will be provided through the cooperative efforts of Douglas County, the Town of Castle Rock, and private entities.

In addition to these projects, other roadway improvements being completed by Douglas County and the Town of Castle Rock are part of the No-Action Alternative (i.e., improvements to local network and maintenance of existing systems). One such roadway improvement within the I-25 Corridor is the construction of a two-lane frontage road along I-25 from Sinclair Boulevard to Castle Rock on the west side of the Union Pacific Railroad and Burlington Northern Santa Fe Railroad tracks. Along the US 85 Corridor, roadway improvements include, but are not limited to, Daniels Park Road and widening Titan Road west of the Plum Creek Bridge.

2.4.1 I-25 Corridor Elements of the No-Action Alternative

Alignment, typical section, and cost for the No-Action Alternative along the I-25 Corridor is described in the following sections.

2.4.1.1. I-25 Corridor Alignment for the No-Action Alternative

The No-Action Alternative is the existing alignment after construction of the Early-Action projects.

2.4.1.2 I-25 Corridor Typical Section for the No-Action Alternative

Typical sections for the No-Action Alternative are shown on Figure 2.2. This alternative consists of six general-purpose lanes between C-470 and Lincoln Avenue, four general-purpose lanes, and two climbing lanes between Lincoln Avenue and Meadows/Founders Parkway, and four general-purpose lanes between Meadows/Founders Parkway and Douglas Lane.

The six-lane section (the same typical as the four general-purpose lanes and two climbing lanes) includes 3.6-meter (12-foot) travel lanes, 3.6-meter (12-foot) outside shoulders, 3-meter (10-foot) inside shoulder, and a 0.6-meter (2-foot) concrete barrier separating the opposing traffic. The total typical section width is 35.4 meters (116 feet). On the outside shoulder of southbound I-25 between Schweiger and Surrey Ridge Road, a Type IV barrier is provided.

The four-lane section includes 3.6-meter (12-foot) travel lanes, 3.0-meter (10-foot) outside and inside shoulders, and a 9.1-meter (30-foot) grass median. The total typical section width is 35.5 meters (116.5 feet).

2.4.1.3. I-25 Corridor Cost for the No-Action Alternative

Because the No-Action Alternative consists of no additional major construction, there are no construction or right-of-way (ROW) costs associated with this alternative along the I-25 Corridor, beyond what is already committed.

2.4.2 US 85 Corridor Elements of the No-Action Alternative

Alignment, typical section, and cost for the No-Action Alternative along the US 85 Corridor is described in the following sections.

2.4.2.1. US 85 Corridor Alignment for the No-Action Alternative

The No-Action Alternative is the existing alignment after the construction of the Early-Action projects.

2.4.2.2. US 85 Corridor Typical Section for the No-Action Alternative

Typical sections for the No-Action Alternative are shown on Figure 2.3. This alternative consists of four lanes between C-470 and Highlands Ranch Parkway and two general-purpose lanes between Highlands Ranch Parkway and Meadows Parkway. Auxiliary lanes are included where they currently exist. The four-lane section includes four 3.6-meter (12-foot) travel lanes, various widths for the median ranging from 0 to 5 meters (0 to 16 feet), and various substandard widths for the outside shoulder ranging from 0.6 meter (2 feet) to 2.4 meters (8 feet). Total typical section width varies from 15.6 to 24.2 meters (51.2 to 79.4 feet).

Figure 2.3 also shows the two-lane typical section. This section includes 3.6-meter (12-foot) travel lanes and various substandard widths for the outside shoulder ranging from 0.6 meter (2 feet) to 2.4 meters (8 feet). Total typical section width south of Highlands Ranch Parkway varies from 8.4 to 12 meters (27.6 to 39.4 feet).

2.4.2.3. US 85 Corridor Cost for the No-Action Alternative

Because the No-Action Alternative consists of no additional major construction, there are no construction or ROW costs associated with this alternative along the US 85 Corridor, beyond what is already committed.

2.5 PREFERRED ALTERNATIVE

The Preferred Alternative was developed based on comments made on the DEIS alternatives and additional analysis. The Preferred Alternative consists of improvements to the I-25 Corridor and US 85 Corridor such as mainline widening, minor realignment, and interchange improvements. All Early-Action projects and the Douglas Lane Interchange are included in this alternative (see Section 2.4, No-Action Alternative). The Preferred Alternative is included in the DRCOG Regional Transportation Plan (RTP) (except the Douglas Lane Interchange) and is the responsibility of CDOT (includes federal, state, and local funds). A schematic of the Preferred Alternative is provided on Figure 2.4.

The FHWA and CDOT have chosen the Preferred Alternative because it best meets the local communities needs and desires, fulfills the project objectives, and provides flexibility in future transportation needs.

Major components of the Preferred Alternative along the I-25 Corridor include:

• Eight lanes (six through lanes and two climbing lanes) between C-470 and Meadows/Founders Parkway
• Six lanes between Meadows/Founders Parkway and Douglas Lane
• Reconstruction of the Schweiger Interchange into a half diamond interchange (improve and reconstruct northern ramps and remove southern ramps)
• Reconstruction of the Surrey Ridge Road Interchange into a three-quarter diamond interchange (improve southern ramps and northbound entrance ramp; remove southbound exit ramp)
• Car pool lot (accommodating 500 spaces) in northeast quadrant of the I-25 and Castle Pines Parkway Interchange
• Minor I-25 realignment to the east between Wolfensberger Road and Liggett Road
• Construction of a new bridge for the Union Pacific Railroad south of the existing bridge
• Supporting measures

Major components of the Preferred Alternative along the US 85 Corridor include:

• Six lanes between C-470 and Highlands Ranch Parkway
• Four lanes between Highlands Ranch Parkway and Meadows Parkway
• US 85/State Highway (SH) 67 Intersection reconfiguration

• Sedalia frontage road
• US 85 minor realignment at Cook Ranch (approximate milepost [MP] 195.4)
• Bicycle/pedestrian facilities along US 85
• High Line Canal Trail grade-separated crossing under US 85
• Enhanced wildlife crossings
• Supporting measures

Acceleration lanes and deceleration lanes are constructed according to CDOT Design Standards at the interchanges. Retaining walls are added, or slope paving adjusted, under the interchange bridges to accommodate roadway widening.

The Southeast Corridor’s ten general-purpose lanes will end on the north end of the C-470 Interchange where two lanes will be dropped in each direction on the north ramps. After a short stretch of six lanes, additional lanes are added at the County Line Road ramps for a total of eight lanes. Traffic studies show that the six-lane section will be sufficient due to the large percentage of entering and exiting vehicles on to and off of the C-470/E-470 Interchange. The six-lane section is between the C-470 north ramps and County Line Road ramps. Figure 2.5a (located at the end of this section) shows the connection to the Southeast Corridor improvements.

Total cost for the Preferred Alternative is $151.6 million. For a breakdown of cost information, see Section 2.9, Alternative Costs. CDOT lacks sufficient funding to build all US 85 elements of the Preferred Alternative. CDOT and Douglas County are working together to find additional funding. If sufficient funds are not found prior to the Record of Decision (ROD), the project work will be prioritized. The Selected Alternative presented in the ROD will be based on available funding.

2.5.1 I-25 Corridor Elements of the Preferred Alternative

Alignment; typical section; changes in travel patterns, access, and safety; and cost for the Preferred Alternative within the I-25 Corridor are described in the following sections.

2.5.1.1. I-25 Corridor Alignment for the Preferred Alternative

The Preferred Alternative generally follows the existing alignment along the entire section of
I-25 (between C-470 and Douglas Lane), with one minor realignment between Wolfensberger Road (MP 182) and Liggett Road (MP 182.5) where the existing centerline shifts to the east by 14 meters (46 feet).

As part of the Climbing Lanes Early-Action projects, the entire interstate is being reconstructed between Lincoln Avenue and Meadows/Founders Parkway, providing for three 3.6-meter (12-foot) travel lanes, 3.6-meter (12-foot) outside shoulder, and 3.0-meter (10-foot) inside shoulder in each direction. As part of the Preferred Alternative improvements, between C-470 and Lincoln Avenue, the interstate is widened to the outside. From Lincoln Avenue to Meadows/Founders Parkway, the shoulder is converted to a travel lane and a new shoulder is constructed. Between Meadows/Founders Parkway and Douglas Lane, the entire interstate is reconstructed with widening primarily to the inside. Figure 2.5a through Figure 2.5i (included at the end of this section, Section 2.5, Preferred Alternative) illustrate the I-25 Corridor alignment for the Preferred Alternative.

2.5.1.2. Additional Major Improvements along the I-25 Corridor for the Preferred Alternative

In addition to the mainline widening, the Preferred Alternative includes:

• Interchange Improvements to Schweiger Interchange and Surrey Ridge Road Interchange. The existing Schweiger Interchange and Surrey Ridge Road Interchange are reconstructed into improved partial interchanges. The southern I-25 ramps at the Schweiger Interchange and the northwest I-25 ramp at the Surrey Ridge Road Interchange are removed. The remaining ramps are reconstructed according to CDOT design standards. This requires relocating approximately 300 meters (980 feet) of Clydesdale Road.
• Castle Pines Parkway Car Pool Lot. A new car pool lot in the northeast quadrant of the Castle Pines Parkway Interchange is constructed. The lot provides for 500 parking spaces and serves as a meeting place and parking area. The car pool lot can be built in phases, starting with a fewer number of parking spaces. The car pool lot may be converted into a park-and-ride lot once transit is operating within the corridor.
• Union Pacific Railroad Bridge. The existing Union Pacific Railroad crosses over I-25 just north of the Wolfensberger Road Interchange. The Preferred Alternative proposes realigning the Union Pacific Railroad Bridge 14 meters (46 feet) to the south of the existing alignment. As a result of this realignment, a new bridge for the Union Pacific Railroad is constructed, and the existing bridge is removed. If ROW issues cannot be resolved with Union Pacific Railroad, the bridge will be reconstructed at the existing location.
• Plum Creek Parkway Bridges and Plum Creek Bridges. The Plum Creek Parkway Bridges and the Plum Creek Bridges are widened and rehabilitated.

2.5.1.3. I-25 Corridor Typical Section for the Preferred Alternative

The Preferred Alternative along the I-25 Corridor consists of eight general-purpose lanes between C-470 and Lincoln Avenue, six general-purpose lanes and two climbing lanes (designated for, but not restricted to slow-moving vehicles) between Lincoln Avenue and Meadows/Founders Parkway, and six general-purpose lanes between Meadows/Founders Parkway and Douglas Lane. Continuous auxiliary lanes are provided between C-470 and Lincoln Avenue, Lincoln Avenue and Schweiger Interchange, and Wolfensberger Road and Plum Creek Parkway. Figure 2.6 shows the typical sections for the Preferred Alternative.

Each lane in the typical eight-lane section of I-25 between C-470 and Lincoln Avenue is 3.6 meters (12 feet) wide. In order to accommodate the proposed improvements in the Southeast Corridor, a southbound inside shoulder variance of 1.2 meters (4 feet) (to be approved by the FHWA) and an outside shoulder of 3.0 meters (10 feet) is included. The northbound inside shoulder is 3.0 meters (10 feet) wide and the outside shoulder is 3.6 meters (12 feet) wide. A concrete barrier 0.6 meter (2 feet) wide, 0.9 meter (2.8 feet) high separates opposing traffic. The total width of the eight-lane typical section is 40.2 meters (132 feet).

Each lane in the typical eight-lane section of I-25 between Lincoln Avenue and Meadows/Founders Parkway is 3.6 meters (12 feet) wide. The outside shoulders of this typical section are 3.6 meters (12 feet) wide, allowing enough room for emergency parking on the roadway. The inside shoulders are 3.0 meters (10 feet) wide, with a concrete barrier 0.6 meter (2 feet) wide (0.9 meter [2.8 feet] high) separating opposing traffic. Total width of the eight-lane typical section is approximately 42.6 meters (140 feet). On the outside shoulder of southbound I-25 between Schweiger and Surrey Ridge Road, a Type IV barrier [0.6 meter (2 feet) wide] is provided.

Each lane in the typical six-lane section of I-25 between Meadows/Founders Parkway and Douglas Lane is 3.6 meters (12 feet) wide. The outside shoulder of this typical section is 3.6 meters (12 feet) wide, allowing enough room for emergency parking on the roadway. The inside shoulder is typically 3.0 meters (10 feet) wide, with a concrete barrier 0.6 meter (2 feet) wide (0.9 meter [2.8 feet] high) separating the opposing traffic. The total width of the six-lane typical section is approximately 35.4 meters (116 feet).

2.5.1.4. I-25 Corridor Changes in Travel Patterns, Access, and Safety for the Preferred Alternative

The Preferred Alternative improves access to the interchanges along the I-25 Corridor between Meadows/Founders Parkway and Douglas Lane by improving the acceleration and deceleration lanes to comply with CDOT design standards. As part of the Climbing Lanes Early-Action projects, the acceleration and deceleration lanes from Lincoln Avenue to Meadows/Founders Parkway are extended to comply with CDOT design standards.

The Preferred Alternative includes safety features such as wider shoulders, concrete median barriers, ramp adjustments, longer acceleration and deceleration lanes, wider structures at the Union Pacific Railroad Bridge and Plum Creek Bridge, and better curve geometry. The realignment of I-25 to the east between Wolfensberger Road and Liggett Road increases the curve radius to improve safety along the roadway. Highway safety is also improved due to the additional capacity that the mainline widening provides.

The new interchange configurations improve the safety for vehicles entering and exiting I-25 at Schweiger and Surrey Ridge Road by providing ramps that comply with CDOT design standards.

The reconstruction of the Schweiger Interchange and Surrey Ridge Road Interchange changes travel patterns because the southern I-25 ramps at the Schweiger Interchange and the northwest I-25 ramp at the Surrey Ridge Road Interchange are removed. With the Preferred Alternative, vehicles that currently access southbound I-25 from the Schweiger Interchange will access southbound I-25 from the Surrey Ridge Road Interchange. Vehicles that currently exit northbound I-25 at the Schweiger Interchange will exit at either the Surrey Ridge Road Interchange or Lincoln Avenue. Vehicles that currently exit southbound I-25 at the Surrey Ridge Road Interchange will exit at the Schweiger Interchange or the Castle Pines Parkway Interchange.

The addition of a car pool lot at the Castle Pines Parkway Interchange changes the travel patterns for people using the lot. Currently, the lot does not exist and people do not exit I-25 and consolidate vehicles. Local neighborhood commuters will meet at the car pool lot to consolidate into one car. The car pool lot may increase the number of vehicles using the Castle Pines Parkway Interchange.

2.5.1.5. I-25 Corridor Cost for the Preferred Alternative

The estimated total cost for the I-25 Corridor elements of the Preferred Alternative is $54.5 million. For a cost breakdown, see Section 2.9, Alternative Costs.

The estimated cost between Lincoln Avenue and Meadows/Founders Parkway is substantially less than between Meadows/Founders Parkway and Douglas Lane because the northern section adds only a shoulder in each direction (majority of improvements constructed as part of Early-Action projects). The majority of the alternative cost is in the southern section because it includes complete reconstruction of the entire cross section.

ROW cost to purchase 10.1 hectares (25 acres) along I-25 is $2.9 million, which is minimal compared to the overall construction cost. It is the intent that this cost is conservative with the anticipation that Douglas County and the Town of Castle Rock will continue to work with CDOT to preserve future ROW as development occurs.

2.5.2 US 85 Corridor Elements of the Preferred Alternative

Alignment; typical section; changes in travel patterns, access, and safety; and cost for the Preferred Alternative within the US 85 Corridor are described in the following sections.

2.5.2.1. US 85 Corridor Alignment for the Preferred Alternative

The Preferred Alternative alignment generally follows the existing alignment with widening to the outside. Exceptions are portions of the roadway at Sedalia and Titan Road where the alignment moves to the northeast and at Cook Ranch (approximate MP 195.4) where the alignment moves to the west.

Beginning at C-470 moving south, the alignment stays along the existing alignment. At Blakeland Drive, the alignment shifts 2.1 meters (7 feet) to the west and then returns to the existing alignment at Highlands Ranch Parkway. The US 85 alignment at Lakeside Drive (approximate MP 197.2) is elevated by approximately 4.2 meters (14 feet) to improve the intersection. Continuing south, the alignment follows the existing alignment to approximately MP 195.4 where it shifts to the west by at most 77.7 meters (255 feet). The alignment returns to the existing alignment at approximately MP 194.9 and continues until MP 190.7.

At approximately MP 190.7 the alignment shifts from the existing alignment to the southeast until approximately MP 187.8 where it returns to the existing alignment. The US 85 alignment at Daniels Park Road runs southwest along the existing alignment to Meadows Parkway. The alignment remains at least 3 meters (10 feet) from the Union Pacific Railroad and the Burlington Northern Santa Fe Railroad ROW throughout the US 85 Corridor.

Figure 2.7a through Figure 2.7h (included at the end of this section, Section 2.5, Preferred Alternative) illustrate the US 85 Corridor alignment for the Preferred Alternative.

2.5.2.2. Additional Major Improvements along the US 85 Corridor for the Preferred Alternative

In addition to the mainline widening, the Preferred Alternative includes the following elements:

• SH 67/US 85 Intersection Reconfiguration and Frontage Road. This improvement includes construction of a short frontage road in the Town of Sedalia (approximately 365 meters [1,200 feet] long). The intersection of SH 67 and US 85 is improved by extending SH 67 to the north with a full-movement signalized intersection. A frontage road is constructed in the southeast quadrant, connecting SH 67 to US 85 at the Cherokee Ranch access road. The intersection of US 85 and the frontage road is stop-sign controlled. The frontage road provides full-movement access to the local Sedalia businesses. Left turns will be prohibited when accessing SH 67 from the frontage road and when accessing the frontage road from SH 67.
• Bicycle/pedestrian facilities along US 85. Bicycle and pedestrian facilities are provided along the US 85 Corridor as described in Section 2.7, Bicycle and Pedestrian Facilities along the US 85 Corridor)
• High Line Canal Trail grade-separated crossing under US 85. See Section 2.7, Bicycle and Pedestrian Facilities along the US 85 Corridor.
• Enhanced wildlife crossings. See Section 2.8, Wildlife Crossings along the US 85 Corridor.

2.5.2.3. US 85 Corridor Typical Section for the Preferred Alternative

Typicals discussed here best minimize environmental impacts while providing safe roadway and roadside design. Typical section width varies depending on the impacts in the area. For example, around Sedalia many environmental and land use impacts force the typical section to be narrower. Multiple typical sections have been discussed and evaluated during the EIS process.

An inside curb and gutter section is generally used throughout US 85. Where reasonable (south of Daniels Park Road), a full 4.6-meter (15-foot) raised median is used. In areas where the typical section needs to be minimized, a 0.9- to 3.1-meter (3- to 10-foot) raised median is used. The raised median physically separates the opposing flows of traffic and control access.

Figure 2.8 shows the US 85 typical sections for the Preferred Alternative. The six-lane section between C-470 and Blakeland Drive includes six 3.6-meter (12-foot) travel lanes, 3.1-meter
(10-foot) raised median, 0.5-meter (1.6-foot) inside curb and gutter, 0.8-meter (2.6-foot) outside curb and gutter, 0.9-meter (3-foot) inside shoulder, 3.0-meter (10-foot) continuous auxiliary lanes, and a 2.4-meter (8-foot) bicycle/pedestrian facility on both sides of the highway. The total typical section is approximately 40 meters (131 feet).

The section between Blakeland Drive and Highlands Ranch Parkway has a total typical section width of 39.6 meters (130 feet). This section includes six 3.6-meter (12-foot) travel lanes,
3.1-meter (10-foot) raised median, 0.5-meter (1.6-foot) inside curb and gutter, 0.8-meter
(2.6-foot) outside curb and gutter, 0.9-meter (3-foot) inside shoulder, 3.0-meter (10-foot) continuous auxiliary lanes, and a detached 3.0-meter (10-foot) bicycle/pedestrian facility on the east side of US 85. The detached bicycle/pedestrian facility changes to an attached facility at the Union Pacific Railroad Bridge due to bridge width restrictions. The attached facility is separated from the highway with a 0.6-meter (2-foot) barrier.

The typical section between Highlands Ranch Parkway and Titan Road includes four 3.6-meter (12-foot) travel lanes, 1.8-meter (6-foot) raised median, 0.5-meter (1.6-foot) inside curb and gutter, 0.9-meter (3-foot) inside shoulder, and two 3.0-meter (10-foot) shoulder/bikeway. The total typical section width is approximately 25.0 meters (82 feet).

The section between Titan Road and IREA has a total typical section width of 26.3 meters (86 feet). There are four 3.6-meter (12-foot) lanes, a 3.1-meter (10-foot) raised median,
0.5-meter (1.6-foot) inside curb and gutter, 0.9-meter (3-foot) inside shoulder, and two 3-meter (10-foot) shoulder/bikeway.

The section between IREA and Sedalia (SH 67) has a total typical section width of 20.9 meters (69 feet). There are four 3.6-meter (12-foot) lanes, a 0.9-meter (3-foot) raised median, 0.5-meter (1.6-foot) inside curb and gutter, and a 3-meter (10-foot) bicycle/pedestrian facility on the south side of the typical section. The narrower typical section is required in this section due to ROW constraints and environmental impacts.

The section between Sedalia and the north end of the Cherokee Ranch (approximately MP 190.1) consists of the typical section described previously between IREA and Sedalia, with the addition of a frontage road on the south side of US 85. The frontage road is separated from US 85 by a grass median that varies in width. The frontage road has two 3.6-meter (12-foot) lanes, 0.8-meter
(2.6-foot) outside curb and gutter, and a bicycle/pedestrian facility on the north side of the frontage road. The total width of this section is 17.9 meters (59 feet).

The section between the north end of the Cherokee Ranch and Daniels Park is the same as described between IREA and Sedalia.

From Daniels Park Road to Meadows Parkway, a wider typical section is used with continuous acceleration and deceleration lanes. There are four 3.6-meter (12-foot) lanes, a 4.6-meter
(15-foot) raised median, 0.5-meter (1.6-foot) inside and 0.8-meter (2.6-foot) outside curb and gutter, 0.9-meter (3-foot) inside shoulder, 3.0-meter (10-foot) acceleration and deceleration lanes, a landscaped area of approximately 1.5 meters (5 feet) between the roadway and the bikeway, and a detached 3.0-meter (10-foot) bicycle/pedestrian facility on the east side. The total typical section width is approximately 33.6 meters (110 feet).

Typical sections may include left-turn lanes, acceleration lanes, and deceleration lanes where appropriate. Continuous auxiliary lanes are used where accesses are spaced closely together. Most business and residential accesses are provided with right-in/right-out access.

Travel patterns change for those accessing the businesses located in the southeast quadrant of the SH 67 and US 85 intersection. The Preferred Alternative improves the intersection of SH 67 and US 85 at Sedalia. The intersection is improved by adding acceleration and deceleration lanes, a frontage road, and a raised median along SH 67. The interchange moves to the northeast, and a frontage road is constructed along the existing US 85 roadway providing access to the Sedalia businesses. Left turns into and out of the frontage road from SH 67 will be prohibited. Travel patterns change for those currently accessing the businesses directly off of US 85 and from SH 67 as well. Under this alternative, businesses in this area must be accessed via the frontage road.

Access points along US 85 are improved in conjunction with the widening of US 85 based on recommendations from the Final US 85 Access Management Plan, February 2001. The purpose of the plan is to improve traffic flow, improve traffic safety, reduce traffic conflicts, and provide appropriate access to adjacent land uses. To meet this objective, existing accesses are consolidated or changed to right-in/right-out. Residents who are provided a limited access of right-in/right-out alter their travel patterns by traveling out of the desired direction to a full-movement access to make a U-turn. Maximum out-of-direction travel is approximately 1.6 kilometers (1 mile). The new SH 67 and US 85 intersection improves access to Sedalia and the businesses.

Safety features incorporated in the Preferred Alternative include wider shoulders, mountable curb, raised median, intersection turn lanes, acceleration lanes, deceleration lanes, and better curve geometry. Highway safety is improved due to the additional capacity that the mainline widening provides and due to the realignment of US 85 at the Cook Ranch property where a curve is minimized. Safety is also improved by reducing traffic conflicts by consolidating access points along US 85. By shifting the SH 67 and US 85 intersection to the northeast, safety and operations are improved by increasing the distance between the railroad tracks and the traffic signal.

2.5.2.5. US 85 Corridor Cost for the Preferred Alternative

The Preferred Alternative assumes the full reconstruction of US 85. Total cost for the US 85 Corridor elements of the Preferred Alternative, assuming full reconstruction of US 85, is approximately $97.1 million. CDOT currently lacks sufficient funding to build all US 85 elements of the Preferred Alternative. CDOT and Douglas County are working together to find additional funding. If sufficient funds are not found prior to the ROD, the project work will be prioritized. The ROD will be based on available funding. For a cost breakdown, see Section 2.9, Alternative Costs.

The ROW/relocation cost for the Preferred Alternative is approximately $17.3 million to purchase 49.4 hectares (122 acres).

2.5.3 Transportation Demand Management Program for Preferred Alternative

A transportation demand management (TDM) program is recommended to complement the Preferred Alternative identified in the South I-25 Corridor and US 85 Corridor FEIS. The following strategies are planned to be implemented in coordination with local communities.

• Smart Community Information Network – Internet and variable message sign (VMS) based local information network provides promotional opportunities, real-time congestion information, and other transportation services.
• Area-wide Ridesharing Programs – Programs and incentives that encourage commuters to use alternatives to driving single occupant vehicle (SOV), and encouraging employers to provide in-house programs that promote ridesharing among employees.
• Commuter Education and Outreach – Education campaign to promote alternative transportation to commuters. Outreach to employers to support employee commute programs. Provides for worksite promotions events.
• Pedestrian/Bicycle Facility – Pedestrian/bicycle facility from the Castle Pines car pool lot to the west side of I-25. Encourages pedestrians and bicyclists to car pool.

The cost for the TDM program is estimated to be $155,000 start-up cost and $130,000 annual cost.

A commitment has been made to implement these strategies. More detail regarding the TDM program is included in the South I-25 Corridor and US 85 Corridor Transportation Demand Management Program Report, December 2000.

2.6 OTHER ALTERNATIVE

The Other Alternative was also developed based on comments regarding alternatives evaluated in the DEIS and additional analysis. This alternative expands and modifies elements included in the Preferred Alternative. The Other Alternative consists of improvements to the I-25 Corridor and US 85 Corridor such as mainline widening, mainline realignment, and major interchange improvements. All Early-Action projects and the Douglas Lane Interchange are included in this alternative (see Section 2.4, No-Action Alternative). A schematic of the Other Alternative is provided on Figure 2.9.

Major components of the Other Alternative along the I-25 Corridor include:

• Eight lanes (six through lanes and two climbing lanes) between C-470 and Meadows/Founders Parkway
• Six lanes between Meadows/Founders Parkway and Douglas Lane
• Diamond interchange at proposed Rampart Range Development
• Reconstruction of the Surrey Ridge Road Interchange to a diamond interchange
• Removal of Schweiger Interchange ramps
• Frontage road on the east side of I-25 from Castle Pines Parkway to proposed Rampart Range Interchange
• Castle Pines Parkway Interchange reconstruction with loop ramp in southeast quadrant
• Car pool lot (accommodating 500 spaces) in northeast quadrant of the I-25 and Castle Pines Parkway Interchange
• Happy Canyon Road Bridge widening
• Minor I-25 realignment to the east between Wolfensberger Road and Liggett Road
• Construction of a new bridge for the Union Pacific Railroad south of the existing bridge
• Supporting measures

Elements not part of the Preferred Alternative along the I-25 Corridor include the completion of a diamond interchange at the proposed Rampart Range Development. If the Rampart Range Interchange is built, the Schweiger Interchange is no longer needed and the Surrey Ridge Road Interchange would be upgraded to a full diamond interchange. A frontage road on the east side of I-25 connecting Castle Pines Parkway to Rampart Range is included to provide local mobility within the corridor. The financial responsibility of these improvements will be determined at a later date.

Major components of the Other Alternative along the US 85 Corridor include:

• Six lanes between C-470 and Titan Road
• Four lanes between Titan Road and Meadows Parkway
• US 85/SH 67 Intersection reconfiguration
• Sedalia frontage road
• US 85 minor realignment at Cook Ranch (approximate MP 195.4)
• Bicycle/pedestrian facilities along US 85 (see Section 2.7, Bicycle and Pedestrian Facilities along the US 85 Corridor)
• Grade-separated crossing under US 85 for High Line Canal Trail (see Section 2.7, Bicycle and Pedestrian Facilities along the US 85 Corridor)
• Enhanced wildlife crossings (see Section 2.8, Wildlife Crossings along the US 85 Corridor)
• Supporting measures

Acceleration lanes and deceleration lanes are constructed according to CDOT design standards at the interchanges. Retaining walls are added or slope paving adjusted under the interchange bridges to accommodate roadway widening.

The Southeast Corridor’s 10 general-purpose lanes will end at the north end of the C-470 Interchange, where two lanes will be dropped in each direction on the northern ramps. After a short stretch of six lanes, additional lanes are added at the County Line Road ramps for a total of eight lanes. Traffic studies show that the six-lane section will be sufficient due to the large percentage of entering and exiting vehicles on to and off of the C-470/E-470 Interchange. The six-lane section is between the C-470 north ramps and County Line Road ramps. Figure 2.10a (located at the end of this section) shows the connection to the Southeast Corridor improvements.

An improvement along the US 85 Corridor included in this alternative is providing six lanes from Highlands Ranch Parkway to Titan Road as opposed to the four lanes shown in the Preferred Alternative. CDOT intends to complete this widening when funding becomes available after the necessary revisions are made to the RTP and ROD.

Total cost for the Other Alternative is $177.5 million. For a breakdown of the cost information, see Section 2.9, Alternative Cost.

2.6.1 I-25 Corridor Elements of the Other Alternative

The alignment; typical section; changes in travel patterns, access, and safety; and cost for the Other Alternative within the I-25 Corridor are described in the following sections.

2.6.1.1. I-25 Corridor Alignment for the Other Alternative

The Other Alternative generally follows the existing alignment along the entire section of I-25 (between C-470 and Douglas Lane) with one minor realignment between Wolfensberger Road (MP 182) and Liggett Road (MP 182.5) where the existing centerline shifts to the east by 14 meters (46 feet).

As part of the Climbing Lanes Early-Action projects, the entire interstate is being reconstructed between Lincoln Avenue and Meadows/Founders Parkway, providing for three 3.6-meter (12-foot) travel lanes, 3.6-meter (12-foot) outside shoulder, and 3.0-meter (10-foot) inside shoulder in each direction. As part of the Other Alternative improvements, between C-470 and Lincoln Avenue, the interstate is widened to the outside. From Lincoln Avenue to Meadows/Founders Parkway, the shoulder is converted into a travel lane and a new shoulder is constructed. Between Meadows/Founders Parkway and Douglas Lane, the entire interstate is reconstructed with widening primarily to the inside. Figure 2.10a through Figure 2.10i (included at the end of this section, Section 2.6, Other Alternative) illustrate the I-25 Corridor alignment for the Other Alternative.

A frontage road is added along the east side of I-25 between Rampart Range and Castle Pines Parkway. The frontage road typical section is shown on Figure 2.11. This frontage road is separated from I-25 by approximately 30 to 343 meters (70.5 to 1,094 feet). This separation provides room for a future transportation envelope (e.g., fixed-guideway). The frontage road flares out at the Surrey Ridge Road Interchange (new diamond interchange), Rampart Range Interchange (new diamond interchange), and Castle Pines Parkway Interchange to provide space for the new interchanges and an additional 180 meters (600 feet) to accommodate traffic signal timing and access spacing requirements.

2.6.1.2. Additional Major Improvements along the I-25 Corridor for the Other Alternative

In addition to the mainline widening, the Other Alternative include:

• Diamond Interchange at Rampart Range. A new diamond interchange at the proposed Rampart Range is constructed approximately 1,460 meters (4,800 feet) south of Lincoln Avenue to service future development. The Rampart Range Interchange exit ramps flare out to accommodate future loop ramps. This improvement is funded by others because the need for the new interchange is driven by proposed development in the area.
• Diamond Interchange at Surrey Ridge Road. The existing Surrey Ridge Road Interchange is reconstructed into a diamond interchange.
• Removal of Schweiger Interchange Ramps. The I-25 ramps at the Schweiger Interchange are removed and Schweiger is connected to the frontage road.
• East-Side Frontage Road from Castle Pines Parkway to Rampart Range. An east-side, two-lane frontage road is constructed between Castle Pines Parkway and Rampart Range. The frontage road may be accessed by Schweiger and Surrey Ridge Road. Local entities are taking the lead in obtaining ROW for the frontage road. Although CDOT is participating in the funding, local funds are also required.

• Partial Cloverleaf Interchange at Castle Pines Parkway. The Castle Pines Parkway Interchange is reconfigured by adding a loop ramp in the southeast quadrant of the Castle Pines Parkway Interchange to improve traffic operations for eastbound to northbound traffic in response to proposed development in the area. For more information on the traffic operations at this interchange, see the South I-25 Corridor Interchange Study, January 2000. Although CDOT is participating in the funding of the improvements to this interchange, local funds are also required due to the development needs.
• Castle Pines Parkway Car Pool Lot. A new car pool lot in the northeast quadrant of the Castle Pines Parkway Interchange is constructed. The lot provides for 500 parking spaces and serves as a meeting place and parking area. The car pool lot can be built in phases, starting with a fewer number of parking spaces. When transit is constructed within the corridor, the car pool lot may be converted into a park-and-ride lot.
• Happy Canyon Road Bridge Widening. The Happy Canyon Road Bridge is widened to provide additional left-turn lanes. Projected traffic volumes warrant the addition of turning lanes to accommodate access onto I-25. Although CDOT is participating in the funding of the improvements to this bridge, local funds are also required due to the development needs. For additional information on projected traffic volumes, see I-25 Corridor and US 85 Corridor Future (2020) Traffic Operations, December 2000.
• Union Pacific Railroad Bridge. The existing Union Pacific Railroad crosses over I-25 just north of the Wolfensberger Interchange. The Other Alternative proposes realigning the Union Pacific Railroad Bridge 14 meters (46 feet) to the south of the existing alignment. As a result of this realignment, a new bridge for the Union Pacific Railroad is constructed, and the existing bridge is removed.
• Plum Creek Parkway Bridges and Plum Creek Bridges. The Plum Creek Parkway Bridge and the Plum Creek Bridges are widened and rehabilitated.

Figures 2.10a through Figure 2.10i show improvements included in the Other Alternative along the I-25 Corridor.

2.6.1.3. I-25 Corridor Typical Section for the Other Alternative

The Other Alternative along the I-25 Corridor consists of eight general-purpose lanes between
C-470 and Lincoln Avenue, six general-purpose lanes and two climbing lanes between Lincoln Avenue and Meadows/Founders Parkway, and six general-purpose lanes between Meadows/Founders Parkway and Douglas Lane. Figure 2.11 shows the typical sections for the Other Alternative.

Each lane in the typical eight-lane section of I-25 between C-470 and Lincoln Avenue is 3.6 meters (12 feet) wide. In order to accommodate the proposed improvements in the Southeast Corridor, a southbound inside shoulder variance of 1.2 meters (4 feet) (to be approved by the FHWA) and an outside shoulder of 3.0 meters (10 feet) is included. The northbound inside shoulder is 3.0 meters (10 feet) wide and the outside shoulder is 3.6 meters (12 feet) wide. A concrete barrier 0.6 meter (2 feet) wide, 0.9 meter (2.8 feet) high separates opposing traffic. The total width of the eight-lane typical section is 40.2 meters (132 feet).

Each lane in the typical eight-lane section of I-25 between Lincoln Avenue and Meadows/Founders Parkway is 3.6 meters (12 feet) wide. The outside shoulders of this typical section are 3.6 meters (12 feet) wide, allowing enough room for emergency parking on the roadway. Inside shoulders are 3.0 meters (10 feet) wide, with a concrete barrier 0.6 meter (2 feet) wide (1 meter [3 feet] high) separating the opposing traffic. Total width of the eight-lane typical section is approximately 42.6 meters (140 feet). On the outside shoulder of southbound I-25 between Schweiger and Surrey Ridge Road, a Type IV barrier [0.6 meter (2 feet) wide] is provided.

Each lane in the typical six-lane section of I-25 between Meadows/Founders Parkway and Douglas Lane is 3.6 meters (12 feet) wide. The outside shoulder of this typical section is 3.6 meters (12 feet) wide, allowing enough room for emergency parking on the roadway. The inside shoulder is typically 3.0 meters (10 feet) wide, with a concrete barrier 0.6 meter (2 feet) wide (0.9 meter [2.8 feet] high) separating opposing traffic. Total width of the six-lane typical section is approximately 35.4 meters (116 feet).

The frontage road between Castle Pines Parkway and Rampart Range includes two 3.6-meter (12-foot) travel lanes and 1.8-meter (6-foot) shoulders. Total width of the frontage road is approximately 10.8 meters (35.5 feet). The frontage road is located at least 9 meters (30 feet) from I-25 to accommodate future transit, this width may be adjusted to accommodate various types of fixed-guideway.

2.6.1.4. I-25 Corridor Changes in Travel Pattern, Access, and Safety for the Other Alternative

The Other Alternative improves access to the interchanges along the I-25 Corridor between Meadows/Founders Parkway and Douglas Lane by improving the acceleration and deceleration lanes to comply with CDOT design standards. As part of the Climbing Lanes Early-Action projects, acceleration and deceleration lanes from Lincoln Avenue to Meadows/Founders Parkway are extended to comply with CDOT design standards.

The Other Alternative includes safety features such as wider shoulders, concrete median barriers, ramp adjustments, longer acceleration and deceleration lanes, wider structures at the railroad and Plum Creek, and better curve geometry. The realignment of I-25 to the east between Wolfensberger Road and Liggett Road increases the curve radius to improve safety along the roadway. Highway safety is also improved due to the additional capacity that the mainline widening provides.

The new diamond interchanges at Rampart Range and Surrey Ridge Road improve safety for vehicles entering and exiting I-25 by providing ramps that comply with CDOT design standards. The Rampart Range Interchange adds new access points along I-25, which increase the likelihood of crashes. The Surrey Ridge Road Interchange does not add another access. The Schweiger Interchange is eliminated by removing the I-25 ramps. Safety conditions here may improve due to a possible decrease in crashes as a result of removing the access to I-25.

The frontage road along I-25 between Rampart Range and Castle Pines Parkway may change travel patterns for those traveling in the vicinity of the frontage road. The frontage road allows residents to access adjacent neighborhoods without using I-25. Included in this alternative is the closure of the Schweiger Interchange, and access is provided to I-25 via the frontage road. The travel patterns of those in the vicinity of the Schweiger Interchange access I-25 from either Rampart Range or Surrey Ridge Road on the frontage road.

Vehicles traveling eastbound on Castle Pines Parkway have improved access on northbound I-25 by providing a loop entrance ramp and eliminating the need for left turns. The eastbound-to-northbound traffic flow is continuous (eliminating left turns), thus improving interchange operations. The loop provides an additional on-ramp to I-25. The Castle Pines loop ramp improves safety for vehicles traveling eastbound onto northbound I-25. The loop ramp eliminates conflict for vehicles currently making left turns. However, the addition of the Castle Pines loop ramp creates another access point on I-25, increasing the possibility of crashes; thus safety conditions may deteriorate along I-25.

The addition of a car pool lot at the Castle Pines Parkway Interchange changes the travel patterns for those using the lot. Currently, the lot does not exist and people do not exit I-25 and consolidate vehicles. Local neighborhood commuters may meet at the car pool lot to consolidate into one car. The car pool lot may increase the number of vehicles using the Castle Pines Parkway Interchange and alter the existing access.

The addition of left-turn lanes on Happy Canyon Road creates greater capacity for the entire intersection and, in return, improves access for those turning onto I-25 to travel either northbound or southbound. Additional left-turn lanes on Happy Canyon Road improve safety by providing more capacity for vehicles making left turns.

2.6.1.5. I-25 Corridor Cost for the Other Alternative

The estimated cost for the I-25 Corridor elements of the Other Alternative is approximately $78.7 million. For a cost breakdown, see Section 2.9, Alternative Costs.

Minimal construction cost is included for the I-25 mainline improvements between Lincoln Avenue and Meadows/Founders Parkway because this section only includes adding a shoulder in each direction. Most of the construction cost for I-25 widening is south of Meadows/Founders Parkway because this section includes complete interstate reconstruction.

A major cost of this alternative is the interchange improvements and frontage road. The ROW increases for this alternative because the frontage road is being constructed on a new alignment. The total ROW required for the Other Alternative is 28.9 hectares (71.4 acres), which costs $8.2 million to purchase. However, it is intended that as part of the Douglas County planning process, future ROW will be preserved as development occurs.

The alignment; typical section; changes in travel patterns, access, and safety; and cost for the Other Alternative within the US 85 Corridor are described in the following sections.

2.6.2.1. US 85 Corridor Alignment for the Other Alternative

The Other Alternative alignment generally follows the existing alignment with widening to the outside. Exceptions are portions of the roadway at Sedalia and Titan Road where the alignment moves to the northeast and at Cook Ranch (approximate MP 195.4) where the alignment moves to the west.

Beginning at C-470 moving south, the alignment stays along the existing alignment. At Blakeland Drive, the alignment shifts 2.1 meters (7 feet) to the west and then returns to the existing alignment at Highlands Ranch Parkway. The US 85 alignment at Lakeside Drive (approximate MP 197.2) is elevated by approximately 4.2 meters (14 feet) to improve the intersection. Continuing south, the alignment follows the existing alignment to approximately MP 195.4 where it shifts to the west by at most 77.7 meters (255 feet). The alignment returns to the existing alignment at approximately MP 194.9 and continues until MP 190.7.

At approximately MP 190.7, the alignment shifts from the existing alignment to the southeast until approximately MP 187.8 where it returns to the existing alignment. The US 85 alignment at Daniels Park Road runs southwest along the existing alignment to Meadows Parkway. The alignment remains at least 3 meters (10 feet) from the Union Pacific Railroad and the Burlington Northern Santa Fe Railroad ROW throughout the US 85 Corridor.

Figure 2.12a through Figure 2.12h (included at the end of this section, Section 2.6, Other Alternative) illustrate the US 85 Corridor alignment for the Other Alternative.

2.6.2.2. Additional Major Improvements along the US 85 Corridor for the Other Alternative

In addition to the mainline widening, the Other Alternative includes:

• SH 67/US 85 Intersection Reconfiguration and Frontage Road. This improvement includes the construction of a short frontage road in the Town of Sedalia (approximately 365 meters [1,200 feet] long). The intersection of SH 67 and US 85 is improved by extending SH 67 to the north with a full-movement signalized intersection. A frontage road is constructed in the southeast quadrant, connecting SH 67 to US 85 at the Cherokee Ranch access road. The intersection of US 85 and the frontage road is stop-sign controlled. The frontage road provides full-movement access to local Sedalia businesses. Left turns will be prohibited when accessing SH 67 from the frontage road and when accessing the frontage road from SH 67.
• Bicycle/pedestrian facilities along US 85. Bicycle and pedestrian facilities are provided along the US 85 Corridor as described in Section 2.7, Bicycle and Pedestrian Facilities along the US 85 Corridor)
• High Line Canal Trail grade-separated crossing under US 85. See Section 2.7, Bicycle and Pedestrian Facilities along the US 85 Corridor.
• Enhanced wildlife crossings. See Section 2.8, Wildlife Crossings along the US 85 Corridor.

2.6.2.3. US 85 Corridor Typical Section for the Other Alternative

Typical sections discussed here best minimize environmental impacts while providing safe roadway and roadside design. Typical section width varies depending on impacts in the area. For example, many environmental and land use impacts around Sedalia force the typical section to be narrower. Multiple typical sections were discussed and evaluated during the EIS process.

An inside curb and gutter section is generally used throughout US 85. Where reasonable, a full 4.6-meter (15-foot) raised median is used. In areas where the typical section needs to be minimized, a 1.8-meter (6-foot) raised median is used. The raised median physically separates opposing traffic flows and controls access.

Figure 2.13 shows the typical section for the Other Alternative. The six-lane section between
C-470 and Blakeland Drive includes six 3.6-meter (12-foot) travel lanes, 3.1-meter (10-foot) raised median, 0.5-meter (1.6-foot) inside curb and gutter, 0.8-meter (2.6-foot) outside curb and gutter, 0.9-meter (3-foot) inside shoulder, 3.0-meter (10-foot) continuous auxiliary lanes, and a
2.4-meter (8-foot) bicycle/pedestrian facility on both sides of the highway. The total typical section is approximately 40 meters (131 feet).

The section between Blakeland Drive and Highlands Ranch Parkway has a total typical section width of 39.6 meters (130 feet). This section includes six 3.6-meter (12-foot) travel lanes, 3.1-meter (10-foot) raised median, 0.5-meter (1.6-foot) inside curb and gutter, 0.8-meter (2.6-foot) outside curb and gutter, 0.9-meter (3-foot) inside shoulder, 3.0-meter (10-foot) continuous auxiliary lanes, and a detached 3-meter (10-foot) bicycle/pedestrian facility on the east side of US 85. The detached bicycle/pedestrian facility changes to an attached facility at the Union Pacific Railroad Bridge due to width restrictions with the bridge. The attached facility is separated from the highway with a 0.6-meter (2-foot) barrier.

The typical section between Highlands Ranch Parkway and Titan Road includes six 3.6-meter (12-foot) travel lanes, 1.8-meter (6-foot) raised median, 0.5-meter (1.6-foot) inside curb and gutter, 0.9-meter (3-foot) inside shoulder, and two 3.0-meter (10-foot) shoulder/bikeway. The total typical section width is approximately 32.2 meters (106 feet).

The section between Titan Road and IREA has a total typical section width of 26.3 meters (86 feet). There are four 3.6-meter (12-foot) lanes, a 3.1-meter (10-foot) raised median, 0.5-meter (1.6-foot) inside curb and gutter, 0.9-meter (3-foot) inside shoulder, and two 3-meter (10-foot) shoulder/bikeway.

The section between IREA and Sedalia (SH 67) has a total typical section width of 20.9 meters (69 feet). There are four 3.6-meter (12-foot) lanes, a 0.9-meter (3 feet) raised median, 0.5-meter (1.6-foot) inside and 0.8-meter (2.6-foot) outside curb and gutter, and a 3-meter (10-foot) bicycle/pedestrian facility on the south side of the typical section. The narrower typical section is required in this section due to ROW constraints and environmental impacts.

The section between Sedalia and the north end of the Cherokee Ranch (approximately MP 190.1) consists of the typical section described previously between IREA and Sedalia, with the addition of a frontage road on the south side of US 85. The frontage road is separated from US 85 by a grass median that varies in width. The frontage road has two 3.6-meter (12-foot) lanes, 0.8-meter (2.6-foot) outside curb and gutter, and a bicycle/pedestrian facility to the north. Total width of this section is 17.9 meters (59 feet).

The section between the north end of the Cherokee Ranch and Daniels Park is the same as described between IREA and Sedalia.

From Daniels Park Road to Meadows Parkway, a wider typical section is used with continuous acceleration and deceleration lanes. There are four 3.6-meter (12-foot) lanes, a 4.6-meter (15-foot) raised median, 0.5-meter (1.6-foot) inside curb and gutter, 0.9-meter (3-foot) inside shoulder, 3.0-meter (10-foot) acceleration and deceleration lanes, a landscaped area of approximately 1.5 meters (5 feet) between the roadway and the bikeway, and a detached
3.0-meter (10-foot) bicycle/pedestrian facility on the east side. The total typical section width is approximately 33.6 meters (110 feet).

The typical section may include left-turn lanes, acceleration lanes, and deceleration lanes where appropriate. Continuous auxiliary lanes are used where accesses are spaced closely together. Most business and residential accesses are provided with right-in/right-out access.

2.6.2.4. US 85 Corridor Travel Patterns, Access, and Safety for the Other Alternative

Travel patterns change for those accessing the businesses located in the southeast quadrant of the SH 67 and US 85 intersection. The Other Alternative improves the intersection of SH 67 and US 85 at Sedalia. The intersection is improved by adding acceleration and deceleration lanes, a frontage road, and a raised median along SH 67. The interchange moves to the northeast, and a frontage road is constructed along the existing US 85 roadway providing access to the Sedalia businesses. Travel patterns change for those currently accessing the businesses directly off of US 85 and from SH 67 as well. Left turns onto and off of the frontage road frontage road from SH67 will be prohibited. Under this alternative, businesses in this area must be accessed via the frontage road.

Access points along US 85 are improved in conjunction with the widening of US 85 based on recommendations from the Final US 85 Access Management Plan, February 2001. The purpose of the plan is to improve traffic flow, improve traffic safety, reduce traffic conflicts, and provide appropriate access to adjacent land uses. To meet this objective, existing accesses are consolidated or changed to right-in/right-out. Residents who are provided a limited access of right-in/right-out alter their travel patterns by traveling out of the desired direction to a full-movement access to make a U-turn. Maximum out-of-direction travel is approximately 1.6 kilometers (1 mile). The new SH 67 and US 85 intersection improves access to Sedalia and the businesses.

Safety features incorporated in the Other Alternative include wider shoulders, mountable curb, raised median, intersection turn lanes, acceleration lanes, deceleration lanes; and better curve geometry. Highway safety is improved due to the additional capacity that the mainline widening provides and due to the realignment of US 85 at the Cook Ranch property where a curve is minimized. Safety is also improved by reducing traffic conflicts by consolidating access points along US 85. By shifting the SH 67 and US 85 intersection to the northeast, safety and operations are improved by increasing the distance between the railroad tracks and the signal.

2.6.2.5. US 85 Corridor Cost for the Other Alternative

Total cost for the US 85 Corridor elements of the Other Alternative is approximately $98.8 million. For a cost breakdown, see Section 2.9, Alternative Costs.

The ROW/relocation cost for the Other Alternative is approximately $17.8 million to purchase 51.4 hectares (127 acres).

2.6.3 Transportation Demand Management Program for the Other Alternative

The TDM program for the Other Alternative is the same as the TDM program for the Preferred Alternative. For additional information, see Section 2.5.3, Transportation Demand Management Program for the Preferred Alternative.

2.7 BICYCLE AND PEDESTRIAN FACILITIES ALONG THE US 85 CORRIDOR

In addition to improving the existing highway, CDOT is also seeking opportunities to improve the entire multi-modal system. Figure 2.14 shows the bicycle and pedestrian facilities along US 85 under consideration in the Preferred Alternative and Other Alternative.

CDOT would prefer a detached bicycle and pedestrian facility along US 85. However, various properties along US 85, including houses, businesses, and Section 4(f) properties, restrict the amount of bikeway that can be detached. As part of the Preferred Alternative and Other Alternative, a detached bicycle/pedestrian facility is located between Blakeland Drive and Highlands Ranch Parkway and between Daniels Park Road and Meadows Parkway. Figure 2.15 is a photo simulation of the detached trail just north of Happy Canyon Road. Where a detached bicycle/pedestrian facility does not fit due to various restrictions, either an attached facility or a large shoulder serves as the bikeway. Multiple bicycle/pedestrian facilities were discussed and evaluated during the EIS process.

Bicycle/pedestrian facilities generally follow the US 85 alignment where possible. Between
C-470 and Blakeland Drive, an attached, 2.4-meter (8-foot) bicycle/pedestrian facility is located on both sides of US 85. Along the east side of US 85 from Blakeland Drive to Highlands Ranch Parkway, a 3.0-meter (10-foot), detached bicycle/pedestrian facility that is separated from US 85 by a 1.5-meter (5-foot) landscaped area is provided. The detached bicycle/pedestrian facility changes to an attached facility at the Union Pacific Railroad Bridge due to width restrictions with the bridge. The attached facility is separated from the highway with a 0.6-meter (2-foot) barrier.

The section between Highlands Ranch Parkway and IREA includes 3.0-meter (10-foot) shoulder/bikeways on both sides of the highway. Along the west side of US 85 from IREA to Sedalia (SH 67), a 3.0-meter (10-foot), attached bicycle/pedestrian facility is provided.

The section between Sedalia and the north end of the Cherokee Ranch (approximately MP 190.1) consists of a frontage road on the south side of US 85. A 3.0-meter (10-foot) bicycle/pedestrian facility is located on the east side of the frontage road. From approximately MP 190.1 to Daniels Park Road, a 3.0-meter (10-foot), attached bicycle/pedestrian facility is located on the west side of US 85. Between Daniels Park Road and Meadows Parkway, a detached, 3.0-meter (10-foot) bicycle/pedestrian facility that is separated from US 85 by a 1.5-meter (5-foot) landscaped area is provided on the east side of US 85.

Bicycle and pedestrian facilities included in the Preferred Alternative and Other Alternative connect to existing paths, such as the High Line Canal Trail. Improvements to the High Line Canal Trail are included as part of the Preferred Alternative and Other Alternative. The trail is realigned to the north and improved into a grade-separated crossing. The crossing is a 3-meter (10-foot) high by 3.7-meter (12-foot) wide culvert. The original High Line Canal Trail remains in place to provide a connection to the US 85 bicycle/pedestrian facility. Figure 2.16 shows the design and typical section of the trail under US 85. Figure 2.17 is a photo simulation showing the new grade-separated crossing and the original trail.

CDOT is committed to continue working with trail groups throughout the design process to develop the best possible design for the bicycle/pedestrian facility within the existing constraints. A design enhancement example is to provide curb inlet grates along US 85 to accommodate bicyclists. It is CDOT's intent to continue to work with Douglas County to try to tie into the existing trail system where possible and to encourage the county to also contribute to improving the current system.

Total cost of the bicycle and pedestrian facilities along the US 85 Corridor for the Preferred Alternative and Other Alternative is $1.2 million. The cost of the High Line Canal grade-separation crossing for the Preferred Alternative and Other Alternative is $0.3 million.

For a detailed description of the US 85 typical sections for the future build alternatives, see Section 2.5.2.3, US 85 Corridor Typical Section for the Preferred Alternative and Section 2.6.2.3, US 85 Corridor Typical Section for the Other Alternative.

2.8 WILDLIFE CROSSINGS ALONG THE US 85 CORRIDOR

The US 85 Corridor bisects open space land used by wildlife. Crucial impacts to wildlife along US 85 are the potential for habitat fragmentation and reduction in wildlife habitat connectivity as a result of the widening. Widening increases the barrier to wildlife attempting to cross over US 85 and further fragments deer and elk habitat.

Tracking studies at existing highway crossings indicate that available bridges and culverts along US 85 are being used by small- to medium-sized mammals. These structures appear to be inadequate for deer and elk due to the small openness factors. The openness factor is defined as the relative openness of an underpass and is calculated as (height x width)/length. CDOW recommends an openness factor of greater than 0.6 for deer crossing and 0.78 for elk crossing. These recommended openness factors have been determined to provide the adequate size needed to encourage deer and elk crossing.

To mitigate wildlife impacts and to enhance existing crossings, two wildlife crossings along US 85 are improved by the future build alternatives. These crossings were strategically chosen based on tracking study results. The first crossing is located on US 85 at MP 195.1 as shown on Figure 2.18. This wildlife crossing is a proposed bridge at the realignment of US 85 near the Cook Ranch property. The proposed crossing is 26.2 meters (86 feet) long, 4.1 meters (13.5 feet) high, and 9.1 meters (30 feet) wide. The openness factor of the proposed bridge is 4.7, which is greater than the recommended factor for elk crossing. A photo simulation of this wildlife crossing is shown in Figure 2.19.

The second crossing is an enhancement of an existing crossing located along US 85 at MP 189.65 as shown on Figure 2.20. The existing crossing is a 2.4-meter (8-foot) by 2.4-meter (8-foot) box culvert 32 meters (105 feet) long. The existing openness factor is 0.61, which is not adequate for elk crossing. The proposed crossing shows an increase in the height of the culvert to 4.1 meters (13.5 feet), which provides an openness factor of 1.0, which is greater than the recommended factor for elk crossing.

The two proposed wildlife crossings are strategically located and provide openness factors to accommodate deer and elk movement. These crossings help maintain habitat connectivity for elk, deer, and other wildlife. The total cost of the wildlife enhancements along the US 85 Corridor for the Preferred Alternative and Other Alternative is $0.3 million. CDOT will coordinate with the CDOW during the design phase in order to determine if any additional wildlife crossing enhancements are needed. For more information on wildlife and wildlife crossings, see Section 4.3.6, Wildlife; Section 5.3.3.6, Wildlife Impacts; and Section 7.3.6, Wildlife.

CDOT has been working with ERTAC to determine wildlife mitigation measures and enhancements. This committee is an advisory group made up of agencies with interests or responsibilities with the ecology within the study area. For more information on ERTAC, see Section 2.2.4, Ecological Resources Technical Advisory Committee.

2.9 ALTERNATIVE COSTS

Preferred Alternative and Other Alternative cost is shown on Table 2.2. The Preferred Alternative assumes the full reconstruction of US 85. Total cost for the US 85 Corridor elements of the Preferred Alternative, assuming full reconstruction of US 85, is approximately $97.1 million. CDOT lacks sufficient funding to build all US 85 elements of the Preferred Alternative. CDOT and Douglas County are working together to find additional funding. If sufficient funds are not found prior to the ROD, the project work will be prioritized. The ROD will be based on available funding.

2.10 ALTERNATIVE VARIATIONS

Previous sections in this chapter presented the No-Action Alternative, Preferred Alternative, and Other Alternative. Based on comments received at the November public open houses, three variations along the I-25 Corridor between Lincoln Avenue and Castle Pines Parkway were suggested and are presented below. One of these alternatives, or an alternative developed from a combination of the three, will likely be the Selected Alternative presented in the ROD.

2.10.1 Variation 1

Variation 1 is the Preferred Alternative with the addition of an east-side frontage road between Schweiger and Surrey Ridge Road, as shown on Figure 2.21. The new east-side frontage road would provide vehicle access to and from I-25 without disrupting the Surrey Ridge residential area.

2.10.2 Variation 2

Variation 2 eliminates the Surrey Ridge Road Interchange and provides an east-side frontage road from Schweiger to Castle Pines Parkway as shown on Figure 2.22. Under this variation, residents of the Surrey Ridge area access I-25 from either the Schweiger Interchange or Castle Pines Parkway Interchange.

2.10.3 Variation 3

Variation 3 eliminates the Schweiger Interchange and Surrey Ridge Road Interchange, provides a new interchange at Rampart Range, and provides an east-side frontage road from Rampart Range to Castle Pines Parkway as shown on Figure 2.23. Under this variation, residents of the Surrey Ridge area access I-25 from either the Rampart Range Interchange or Castle Pines Parkway Interchange.

2.11 THE LONG-TERM VISION FOR SOUTH I-25 AND US 85 THROUGH 2020 AND BEYOND

The Long-Term Vision for South I-25 and US 85 Through 2020 and Beyond (referred to as the Long-Term Vision) was developed through the previously discussed extensive evaluation and public/agency involvement process. The Long-Term Vision reflects improvements that meet the purpose and need and/or are desired through community values and agency support. Because the Long-Term Vision assumes no fiscal constraints, not all of the elements included in the Long-Term Vision have been included in the FEIS build alternatives. Major elements of the vision are discussed in the following sections and are shown on Figure 2.24. Upon adoption of this FEIS by FHWA and CDOT, these items will be conveyed to DRCOG with a request for inclusion in Metro Vision.

2.11.1 I-25 Corridor Long-Term Vision Elements

2.11.1.1. Additional General-Purpose Lanes from C-470 through Castle Rock

One additional lane is added in each direction from C-470 to Douglas Lane. The final configuration is eight lanes between C-470 and Meadows/Founders Parkway and six lanes between Meadows/Founders Parkway and Douglas Lane. This element of the Long-Term Vision is evaluated in the Preferred Alternative and Other Alternative.

2.11.1.2. I-25 Fixed-Guideway

The Long-Term Vision includes fixed-guideway along I-25. The fixed-guideway in the Long-Term Vision extends from the Southeast Corridor terminus, north of Lincoln Avenue to Castle Rock. Proposed stations are located at the Rampart Range Development, Castle Pines Parkway, Meadows/Founders Parkway, and Castle Rock. Future construction of this element is provided for as a transportation envelope (located between I-25 and the frontage road) between Lincoln Avenue and Castle Pines Parkway in the Other Alternative. Fixed-guideway is not anticipated to be constructed in the next 20 years, but CDOT has been coordinating with Douglas County, the Town of Castle Rock, and the City of Lone Tree to not preclude future fixed-guideway options.

Fixed-Guideway Alignment

The tentative conceptual alignment of the fixed-guideway is shown on Figure 2.25. The fixed-guideway alignment extends south from the Southeast Corridor terminus at Lincoln Avenue along the west side of I-25. The alignment crosses I-25 near the Lincoln Avenue Interchange. This crossing may be either north or south of the interchange and may be either an overpass or tunnel. (For cost estimating purposes, the fixed-guideway alignment is assumed to cross north of Lincoln Avenue through a tunnel.) After the fixed-guideway crosses I-25, the alignment closely parallels I-25 on the east side and curves around interchanges to reach stations.

The southern terminus of the fixed-guideway has not been finalized. The final determination will be part of the planning effort for fixed-guideway construction. Several options within the Town of Castle Rock have been identified as potential termini:

• Meadows/Founders Parkway
• Downtown Castle Rock

• Plum Creek Parkway

Meadows/Founders Parkway. The fixed-guideway could terminate near the Meadows/Founders Parkway Interchange. Three alignment options exist for this terminus. One option is to continue the alignment on the east side of I-25 and terminate just north of the houses along Allen Street. This option includes a pedestrian overpass that connects the fixed-guideway station to the Prime Outlets.

A second option is located at the Meadows/Founders Interchange and crosses the fixed-guideway from the east side of I-25 to the west side of I-25 and ends at the Prime Outlets.

The third option examines the location of a fixed-guideway terminus near the Prime Outlets that accommodates possible future rail corridors along I-25 and US 85.

Downtown Castle Rock. The fixed-guideway could terminate in downtown Castle Rock. Two alignment options exist for this terminus. One option is to continue the alignment on the east side of I-25 and continue up the Wilcox northbound entrance ramp. The fixed-guideway alignment is adjacent to the east side of Wilcox Street and terminates at 5th Street.

Another option for the fixed-guideway ending in downtown Castle Rock is to continue the alignment on the east side of I-25 and connect to the existing railroad tracks. The fixed-guideway could use the existing tracks into downtown Castle Rock, dependent on the existing railroad tracks being relocated.

Plum Creek Parkway. The fixed-guideway may terminate at Plum Creek Parkway. The alignment for this option continues on the east side of I-25 and terminates at the Plum Creek Parkway Interchange.

This FEIS provides for the fixed-guideway alignment between Lincoln Avenue and Castle Pines Parkway in the Other Alternative (between I-25 and Frontage Road). Several options for the alignment are available at the other locations. These decisions will be made after additional evaluation is completed.

Figure 2.26 shows the fixed-guideway typical section. A concrete barrier and 3.6-meter (12-foot) shoulder separate the fixed-guideway from the highway. The double-track, fixed-guideway is located on the east side of I-25 in a 9.1-meter (30-foot) envelope. The fixed-guideway envelope may be revised (for example, 9.4-meter [31-foot] wide to match the Southeast Corridor envelope) after additional evaluation is completed and at the time of final design.

The cost for the fixed-guideway was developed as part of the second level of evaluation and was used only for comparison purposes with the other alternatives. The cost is estimated at $105 million and would need to be re-evaluated in the future. The estimated cost assumes single-track, and diesel multiple unit (DMU) commuter rail. It includes tunneling beneath I-25 north of Lincoln Avenue. The alignment begins at Lincoln Avenue and continues to Plum Creek Parkway. The cost is conceptual and does not include ROW costs, although some of the ROW costs are included in the Other Alternative. The above assumptions were made for comparison purposes only. The type of fixed-guideway alignment and station locations should be re-evaluated closer to the time of implementation.

Based on the recommendations of the I-25 Interchange Study and the public process, the following improvements or options are included in the Long-Term Vision:

• Construct new interchange at Rampart Range (funded privately) or reconstruct Surrey Ridge Road Interchange as a diamond
• Build frontage road between either Castle Pines Parkway and Rampart Range or Castle Pines Parkway and Lincoln Avenue
• Reconstruct or relocate the I-25/Schweiger (exit 191) Interchange
• Close the I-25/Surrey Ridge Road Interchange and relocate access to the north or south

• Add a southeast quadrant loop ramp at the I-25/Castle Pines Parkway Interchange to serve eastbound Castle Pines Parkway to northbound I-25
• Widen Happy Canyon Road over I-25 to provide for additional through lane and turn lane
• Reconstruct Plum Creek Parkway either in existing location as a single-point urban interchange or at a new location to the south as a diamond interchange
• Construct new diamond interchange at Douglas Lane (funded privately)
• Review operational characteristics of freeway merge and diverge at Larkspur/Palmer Lake Interchange and provide improvements as necessary

2.11.1.4. Preservation of Future Transportation Options along I-25

As part of the Long-Term Vision, none of the constructed improvements will preclude future transportation options. CDOT encourages local entities to obtain transportation easements from developers as part of their referral process. As discussed in the DEIS, CDOT has been working with Douglas County, the Town of Castle Rock, and City of Lone Tree to provide for and preserve mass transit and bicycle facilities. Each of these agencies has been supportive in implementing mass transit and providing for bicycle facilities. Examples where CDOT is preserving ROW include providing for mass transit along the east side of I-25 (shown in the Other Alternative) between I-25 and the proposed frontage road and the inclusion of a car pool lot in the FEIS that may be converted into a park-and-ride lot at a future date. Douglas County and the Town of Castle Rock are working with developers to provide a transportation easement along both US 85 and I-25 for future improvements. The City of Lone Tree has been working with the Rampart Range Development in extending light rail transit (LRT) from the Southeast Corridor terminus. RTD boundaries do not include the Town of Castle Rock. The only RTD bus operating in the study area is the Highlands Ranch Town Center Express. Several years ago the residents of the Town of Castle Rock voted against expanding RTD service into Castle Rock.

2.11.1.5. I-25 Alternate Routes

Crowfoot Valley Road is improved to provide for a local access alternate route to I-25. Improvements include upgrading Crowfoot Valley Road to Stroh Road to four-lane arterials between Founders Parkway and Parker Road. This improvement helps the local network and is currently part of Douglas County’s planned improvements. This alternate route will need to be funded by others.

2.11.1.6. Supporting Measures

As part of the overall corridor plan, measures that support mobility and safety are desirable. These measures include TDM, transportation system management (TSM), and intelligent transportation systems (ITS). Supporting measures may also include, but are not limited to, car pool/park-and-ride lots, bus feeder systems, and cross-platform transfers. CDOT has initiated an I-25 incident management study that evaluates strategies to handle incidents along I-25.

2.11.1.7. Car Pool Lots

Car pool lots are included as elements of the Long-Term Vision. These lots are designed to encourage travelers to car pool to their destination. A car pool lot is being evaluated in the FEIS build alternatives along I-25 at the northeast quadrant of the Castle Pines Parkway Interchange (see Section 2.5.1.2, Additional Major Improvements along the I-25 Corridor for the Preferred Alternative). Other car pool lots are included in the Long-Term Vision but are not being fully evaluated in this FEIS. Environmental clearances will be completed for these car pool lots prior to ROW purchase and construction. Proposed locations include:

• The proposed Rampart Range/I-25 Interchange
• Meadows/Founders Parkway Interchange
• Downtown Castle Rock

Car pool lots are being designed to be converted into park-and-ride facilities when the fixed-guideway transit is extended to Castle Rock.

2.11.2 US 85 Corridor Long-Term Vision Elements

One general-purpose lane is added in each direction between C-470 and Meadows Parkway. The Long-Term Vision lane configuration is six general-purpose lanes between C-470 and Titan Road and four general-purpose lanes between Titan Road and Meadows Parkway. This element is evaluated in the Other Alternative.

2.11.2.2. Bus Feeder Service from Highlands Ranch Parkway to the Mineral Avenue Light Rail Transit Station

A bus service is provided as a feeder system to the Mineral Avenue LRT station and park-and-ride. As part of this, a new park-and-ride lot will be located along US 85 in the vicinity of Highlands Ranch Parkway. The buses will use the general-purpose lanes. RTD currently operates circulation routes to feed the Mineral Avenue LRT station.

2.11.2.3. US 85 Transit Rail Demonstration Project

Included in the Long-Term Vision is a Transit Demonstration Project along US 85. A potential demonstration project is being investigated as an independent study. (CDOT is not leading this effort.) This project is exploring the option of connecting a commuter rail line to the Southwest Corridor LRT terminus at Mineral Avenue to determine potential ridership of a permanent rail line. An independent group is evaluating the cost and operations of three commuter rail options operating on or parallel to the existing freight railroad tracks from Mineral Avenue to downtown Castle Rock. All three options include a cross-platform transfer at the Mineral Avenue LRT station. Train times are scheduled to coincide with peak hour demand, although off-peak service is also offered. Travel time from Castle Rock to Mineral Avenue is approximately 35 minutes, making the total trip time from Castle Rock to Denver approximately 1 hour. The following three options are being evaluated by the group:

Option A: Six-Month to One-Year Demonstration Project

Option A is a six-month to one-year demonstration that operates with one train set making continuous round trips. It includes minimal mainline improvements, assuming the trains can feasibly operate on the existing tracks.

Option B operates on an annual basis using 4 train sets, making a total of 14 daily train trips (7 inbound, 7 outbound). It includes moderate mainline improvements, assuming the trains can operate on a portion of the existing track. The trains operate mostly on the existing freight track with an additional 9.6 kilometers (6 miles) of new siding and station area track.

Option C operates on a permanent basis using four train sets, making a total of 18 daily train trips (9 inbound, 9 outbound). The trains operate on a newly constructed track connecting Castle Rock to the Mineral Avenue LRT station.

The Commuter Rail Between Castle Rock and Mineral Avenue, January 2000 provides more details of the demonstration project.

2.11.2.4. Preservation of Future Fixed-Guideway Corridor along Existing Rail Corridor

As part of the Long-Term Vision and the Rail Corridor Preservation Policy, the existing rail corridors are preserved for future transit use. If the existing rail corridor is abandoned, the land is preserved for future fixed-guideway transit, and none of the roadway improvements constructed preclude future fixed-guideway. The Rail Corridor Preservation Policy Directive 1906, adopted by CDOT on April 19, 1000, requires CDOT to consider passenger and freight rail transportation. This includes developing criteria used in defining rail corridors of state interest and describing rail activities in which CDOT may engage. Since the existing rail corridor included in the South I-25 Corridor and US 85 Corridor FEIS has been designated as a rail corridor of state significance, CDOT is required to design and construct roads and roadway related structures that will preserve an envelope sufficient for future rail service unless physically or financially prohibited. The Preferred Alternative and Other Alternative remain at least 3 meters (10 feet) from the Union Pacific Railroad ROW and the Burlington Northern Santa Fe Railroad ROW.

2.11.2.5. US 85 Alternate Routes

Santa Fe Drive (US 85) is extended to the south at approximately Meadows/Founders Parkway along I-25 to provide for an alternate route to US 85. Improvements include extending and upgrading US 85 (Santa Fe Drive) to a four-lane arterial between the existing Castlegate Drive and downtown Castle Rock. This alternate route is under the jurisdiction of the Town of Castle Rock, and planning and funding will ultimately be their responsibility.

2.11.2.6. Supporting Measures

As part of the overall corridor plan, measures that support mobility and safety are desirable. These measures include TDM, TSM, and ITS. Supporting measures may also include, but are not limited to, car pool/park-and-ride lots, bus feeder systems, and cross-platform transfers. Another supporting measure is the Final Access Management Plan for US 85, November 2000.

The South I-25 Corridor and US 85 Corridor Transportation Demand Management Program Report, December 2000, details TDM measures included in the Preferred Alternative.

2.11.3 Responsibility of Long-Term Vision Elements

Because of jurisdictional and funding constraints, CDOT cannot be responsible for all elements of the Long-Term Vision. Other agencies/groups (i.e., Douglas County, the Town of Castle Rock, Rampart Range Development Group) have jurisdiction over some elements. Potential responsibilities are outlined in Table 2.3 and will be refined as the different elements are developed.

2.12 ALTERNATIVES ELIMINATED FROM CONSIDERATION

A three-level evaluation process was developed to reduce the number of alternatives fully evaluated in the EIS to those that are reasonable and meet the project purpose and need. The first level of evaluation eliminates unrealistic alternatives; the second level of evaluation eliminates alternatives based on how well they compare with the other alternatives; and the third level of evaluation evaluates combinations of alternatives to determine how well the alternatives work together. The Long-Term Vision is dev