Purpose and Need

The following information is a summary of the Purpose and Need. Review the entire Purpose and Need in the FEIS, Chapter 1, 'Purpose and Need'. (You will need Adobe Acrobat Reader to view this document.  If you do not have it, please use this link to download your free copy: Adobe Acrobat Reader.)

Problem Statement

The goal of the Purpose and Need is to establish why CDOT is proposing to improve the transportation system. The Purpose and Need identifies current and future deficiencies of the existing transportation system. It outlines the reason for improvements and sets a basis for the alternative analysis.

Based on the Purpose and Need, the following Problem Statement was developed:

The north/south peak travel demand in northern Douglas County has grown at a pace faster than the surrounding metropolitan area. These trips, primarily to jobs in downtown Denver and the Denver Tech Center, have overtaxed the existing infrastructure. North/south travel options beyond the use of automobiles on I-25 and US 85 are limited.

I-25

Traffic volumes and speeds on I-25 exceed the design during the a.m. and p.m. peak hours. The result is congestion, delays, and crashes, exacerbated by adverse weather. I-25 is the focus for the inter-regional travel and the majority of the commuter trips originating in Douglas County. Forecasts of future demand show continued overtaxing of the I-25 facility resulting in more hours of unacceptable congestion, longer delays, and more crashes.

US 85

The US 85 Corridor has one lane in each direction. In many locations left and right turn lanes do not exist. This results in a high number of crashes and dangerous driving, such as passing slower vehicles on the shoulders. US 85 provides for some short distance regional trips and many local trips. US 85 is the 'local street' for communities such as Sedalia and Louviers. Turning on to and off of US 85 is difficult because of the speed and volume of the mainline traffic. Forecasts of future demand show increased driver frustration resulting in increased crashes and reduced accessibility.

Previous Studies

Based on the results of the South Front Range Corridor Assessment Study (CAS) and the U.S. Highway 85 Environmental Assessment (EA), the Colorado Department of Transportation (CDOT) and the Federal Highway Administration (FHWA) determined the need for the South I-25 Corridor and US 85 Corridor Environmental Impact Statement (EIS).

South Front Range Corridor Assessment Study

The I-25 Corridor and US 85 Corridor have been the topic of several previous studies. The South I-25 Corridor and US 85 Corridor EIS is primarily a result of the South Front Range Corridor Assessment Study (CAS) and the U.S. Highway 85 Environmental Assessment.

In the fall of 1997, CDOT began the South Front Range CAS, a multi-modal study of the I-25 Corridor, from Denver to Pueblo. The South Front Range CAS analyzed the inter-regional travel demand (i.e., traffic traveling between Denver, Colorado Springs, and/or Pueblo) on I-25.

This study determined that I-25 has sufficient capacity to accommodate projected inter-regional travel demand through the year 2020, although with significantly diminished levels of service. However, beyond the year 2020, the existing I-25 capacity will fail to meet the inter-regional travel demand between Denver and Colorado Springs.

The findings of the South Front Range CAS allowed studies of capacity improvements, within the urban areas of Denver and Colorado Springs, to proceed independently. Therefore, to address the inter-regional transportation needs on I-25 in Douglas County, CDOT, with cooperation from FHWA is undertaking an EIS between Denver and Castle Rock.

U.S. Highway 85 Environmental Assessment

In June 1994, CDOT completed the U.S. Highway 85 Environmental Assessment (EA). This document evaluated transportation improvements along US 85 from C-470 to I-25 at Castle Rock. The primary element of the improvement was to upgrade the existing highway, which included the following: widening the highway to 6 lanes between C-470 and Titan Road, widening to 4 lanes between Titan Road and I-25, correcting design deficiencies, improving the intersection at Titan Road, adding acceleration, deceleration, and turn lanes at appropriate locations, implementing access control in the corridor, and realigning the highway in two locations to provide necessary separation from the railroad tracks.

Based on the results of the U.S. Highway 85 EA, CDOT and FHWA determined that the proposed project warrants preparation of an EIS.

Feasible solutions for the I-25 Corridor and US 85 Corridor are currently being analyzed to establish the Long-Term Vision. The analysis consist of an evaluation of each alternative's ability to meet the Purpose and Need. The following is a detailed description of the Purpose and Need that the South I-25 Corridor and US 85 Corridor EIS project addresses:

Traffic Characteristics

• Existing Conditions along I-25 and US 85

• Traffic Volumes
  The existing (1998) traffic volumes are analyzed along both the I-25 Corridor and US 85 Corridor. This analysis includes Annual Average Daily Traffic (AADT) and peak hour traffic volumes. Existing volumes help determine areas that are over capacity.
  

• Traffic Operations
  The current traffic operations are also analyzed for both corridors. This includes a level-of-service analysis for freeway segments (I-25), rural highway segments (US 85), intersections, interchanges, and ramps.

• Other Characteristics
  Other traffic characteristics that may be relative to the study are analyzed. These may include seasonal variation, weekly variation, and daily variation.

Click the link for Detailed Information regarding the Annual Average Daily Traffic (AADT), Peak Hour Volumes, and Level of Service (LOS) ratings for I-25 and US 85 within the EIS Corridor: Existing Traffic Conditions

• Traffic Growth in the Corridors

• 2020 Traffic Volumes
  Projected 2020 traffic volumes along each corridor, based on the traffic demand model are both analyzed. These volumes are estimated assuming all Early-Action projects (Projects 1 through 7) are completed (No-Action volumes). Future traffic volumes (AADT and peak hour) help identify areas that are over capacity in year 2020.
  

• 2020 Traffic Operations
  Level-of-service analysis for freeway segments (I-25), rural highway segments (US 85), intersections, interchanges, and ramps using the projected 2020 traffic volumes (No-Action operations) are completed.
  

• Other Characteristics
  Other traffic characteristics based on the projected 2020 traffic volumes that may be relative to the study are evaluated.

Click the link for Detailed Information regarding the 2020 Annual Average Daily Traffic (AADT), 2020 Peak Hour Volumes, and 2020 Level of Service (LOS) ratings for I-25 and US 85 within the EIS Corridor: Future Traffic Conditions

Safety

• Crash History
The crash history between 1995 and 1997 for both I-25 and US 85 was collected and evaluated. This includes the number, type, location, weather conditions, and direction of the accident. A detailed analysis of problem areas was completed to determine areas of deficiencies.

• Roadway Deficiencies
Roadway, interchange, and intersection deficiencies along I-25 or US 85 have been identified. On I-25, some of the roadway deficiencies include substandard acceleration/deceleration lanes, inadequate interchanges, and steep grades. On US 85, some of the roadway deficiencies include narrow travel lanes, inadequate shoulders, poor sight distance, and a lack of acceleration/deceleration lanes.

Click the link for Detailed Information regarding the crash frequencies & rates for
I-25 and US 85 within the EIS Corridor: Safety Analysis

Mobility

How the study corridors (both I-25 and US 85) provide access to the Denver Tech Center, Denver Metropolitan area, and Colorado Springs will be discussed. This discussion is centered around the importance of the project corridor in the overall transportation system.

System Linkages

The study corridors are major north/south connectors that are used by commuters, truckers, travelers, and local residents. How the study corridors (I-25 and US 85) link to the local network and other transportation modes within the area will be completed.

• Local Network
The local networks and the relationship they have within the study corridors will be evaluated. This includes identifying the role the corridors play in the local residents transportation system.

• Potential LRT Extension(s)
Currently a Light Rail Transit (LRT) system is being constructed along Santa Fe that ends at Mineral Avenue. Also, an EIS is currently being conducted that is recommending extending LRT from Broadway Avenue to Lincoln Avenue along I-25. The South I-25 Corridor and the US 85 Corridor EIS has the opportunity to extend one or both of these systems through Castle Rock.

• Heavy Rail
Burlington Northern/ Santa Fe and Union Pacific Rail currently have lines that run through the study area. Existing operations and the potential for the addition of passenger rail will be evaluated.

• Potential Bus Connection
The existing Regional Transportation District bus system does not include the majority of the study area. The opportunity of extending the service through Castle Rock will be evaluated.

Economic Development

Any projected economic development/land use changes that may indicate the need to improve the current transportation system will be evaluated.

• Transportation Plans
The relationship between the study corridor and any statewide plan or adopted town transportation plan will be evaluated. The Long-Term Vision must fit into the adopted plans.