The statistics from the Fatality Analysis Reporting System (FARS) show that in 2001 Colorado had 643 fatal crashes, with 287 of these crashes identified as single-vehicle, run-off-the-road crashes.

GOALS AND OBJECTIVES

The goal of this project is to reduce run-off-the-road crashes on interstate highways while preserving safety for bicyclists riding on the shoulders (where permitted).

STRATEGIES AND ACTIVITIES

The Colorado Department of Transportation (CDOT) initiated a Statewide Rumble Strip project. The installation of shoulder rumble strips on 86.5 miles of I-25, 142.8 miles on I-70, and 61 miles on I-76 will result in continuous rumble strips on the interstate system throughout the rural sections of the state (excludes the Denver Metro area).

While rumble strips save lives and reduce property damage for motorists, they can be a problem for bicyclists riding on the shoulder. The Colorado bicycle community encouraged CDOT to identify a rumble strip design that is bicycle friendly. As a result, CDOT now uses a ground-in rumble strip, grinding the grooves to a depth of 3/8 inch (+ 1/8 inch). This depth provides a relatively high level of sound and vibration in motor vehicles and can be safely crossed by a bicycle. Also, the rumble strips are placed on the outside edge of the travel lanes’ edge line (no offset) to allow for maximum shoulder width unobstructed by rumble strips for bicyclist use.

Access CDOT’s standard rumble strip plans using the following hyperlink:

http://www.dot.state.co.us/DesignSupport/MStandards/2000_M_Standards/2000%20Roadway%20Geometry%20and%20Pavement/Roadway.htm.

Additionally, the Bicycle-Friendly Rumble Strip Study Report can be viewed by accessing the following hyperlink: http://www.dot.state.co.us/publications/researchreports.htm.

RESULTS

The project was awarded in February, and all work will be complete by September 30, 2003. No estimates of lives saved have been made at this time. Typically, an evaluation will be made using data from three years before and three years after to determine the percentage improvement in safety.