Researchers found that deployment of a speed management system for winter weather operations reduced crashes and improved safety.
In June 2012 U.S. DOT finalized Version 3.0 of the Best Practices for Road Weather Management report. This report contains 27 case studies of systems in 22 states that improve roadway operations under inclement weather conditions. Each case study has six sections including a general description of the system, system components, operational procedures, resulting transportation outcomes, implementation issues, as well as contact information and references.
The previous report, Best Practices for Road Weather Management Version 2.0 presented 30 case studies from municipal and state transportation agencies. At this point, those solutions are either mainstreamed or have been surpassed by even better solutions. The Version 3.0 report captures the state-of-the-art, presenting 27 all-new practices that build upon these agencies’ previous successes.
System Operations: The system provides continuous monitoring of atmospheric and pavement weather conditions to determine changing driving conditions that will impact the motorist and alert transportation managers of these changing conditions. The Non-Invasive pavement weather sensors are capable of monitoring changing traction values that will impact driving conditions for the motorist. They are also capable of alerting the motorist of these conditions by displaying messages on the variable message sign and potentially providing advisory speed limits as a result of these changing pavement conditions.
The system monitors current atmospheric conditions by monitoring when precipitation is occurring in the form of rain, freezing rain, or snow, with the ability to display rates and accumulations. The system is able to provide alerts to Colorado Department of Transportation (CDOT) operations of these changing atmospheric and pavement weather conditions allowing for remote access to conditions by computer and cell phone. The camera allows for live images of changing weather conditions at the site. The system monitors traction level thresholds. When slippery thresholds for wet and icy thresholds are reached, activation of different messages such as "Wet Roads Ahead" or "Icy Roads Ahead" are produced by the RWIS processor. The "wireless device control", utilizing spread spectrum radios, activates these different messages in the VMS that is located nearly a mile in advance of this stretch of highway. The "wireless device control" also is capable of providing different controls for different suggested speeds with the "variable speed sign".
- The unique road topography of Colorado State Highway 82 caused shading and precipitation build-up on certain portions of the road at various times of the day, resulting in a large number of winter weather related accidents during the several years prior to the installation of this Intelligent Transportation System. The first winter of operation resulted in zero (100 percent reduction) winter weather related accidents in this section of highway in Snowmass Canyon.