History & Purpose

The Climbing Lanes, Phase I project is an Early-Action Project. This project addresses immediate safety issues identified by the inter-regional commuters through the South Front Range Corridor Assessment Study completed in April 1998.

These improvements are continued with the Climbing Lanes, Phase II project, already under construction, completing similar safety improvements from the Castle Pines Parkway Interchange to the Meadows/Founders Parkway Interchange.

The following conditions required immediate action:

The safety of the traveling public is frequently compromised by slow moving vehicles (predominately trucks) climbing steep grades characteristic of this section of I-25. These vehicles are a constant disruption to the mainline traffic stream causing safety hazards associated with a mix of vehicles moving at significantly different speeds. Frequent breakdowns, heavy traffic and adverse weather conditions compound the problem. Trucks account for approximately 11% of the traffic volume between Denver and Colorado Springs.

A design solution which could be implemented quickly was required to relieve this situation.

A 3.6-meter (12-foot) climbing lane in each direction, as well as widened inside and outside shoulders, was designed within these parameters to minimize the disruption to the mainline traffic stream and result in safer more consistent operating speeds. The wider shoulders [3-meter (10-foot) median shoulder and 3.6-meter (12-foot) outside shoulder] accommodate breakdowns.