CDOT to continue Rolling Speed Harmonization (pace car) tests on Interstate 70 this weekend

The Colorado Department of Transportation (CDOT), in coordination with the Colorado State Patrol (CSP), and Silverthorne Police Department (SPD), will be testing Rolling Speed Harmonization for a second time this weekend, along a longer stretch of Interstate 70.

Beginning at approximately 10 a.m. on Sunday, September 25, a single SPD car will switch on its emergency lights and merge ahead of traffic, starting just east of the Silverthorne Interchange. The police vehicle will use the center or left lane to pace eastbound vehicles, at speeds between 45 and 55 mph, to the entrance of the Eisenhower/Johnson Memorial Tunnel (EJMT).

At the entrance point, the SPD then will hand-off to the CSP, with the CSP pacing vehicles through the EJMT and east 18 miles to U.S. 40 (Empire Junction).

The 27-mile pacing operation will repeat about every five to 10 minutes, until around 2 p.m.

This Sunday's operation is a follow-up to a test conducted on Saturday, August 13, along eastbound I-70 from Silverthorne to the EJMT. Data collected from that test indicated Rolling Speed Harmonization created more uniform speeds for vehicles, and as a result, could improve safety, reduce traffic crashes and ultimately improve traffic flow on the corridor.

It also showed very high compliance and speed differentials were reduced, even between vehicle platoons – a key determinant since wide variations in speed lead to higher probability of accidents which, in turn, substantially increases congestion. Communication and operational coordination also worked well between CDOT, CSP and SPD.

“This will be a more extensive test since we're investigating how traffic flows over a much longer stretch of highway and on a Sunday, when the volume of traffic tends to be significantly higher than on Saturday,” said CDOT Regional Transportation Director Tony DeVito. “We're asking drivers who become part of the pacing operation to please use caution and cooperate with the officers who are conducting the operation.”

Traffic counts during the August 13 test period averaged between 1,200 and 1,500 vehicle per hour on eastbound I-70. Sunday counts in late September tend to average between 1,800 and 2,300 vehicles.

“Rolling Speed Harmonization can be considered a successful way to maximize traffic flow, improve safety and lower the number of accidents, which is a big contributor to traffic congestion,” added DeVito, “and that congestion leads to metering at the tunnel, which we would like to reduce since it inconveniences our customers on the corridor.”

CDOT holds or “meters” eastbound traffic at the tunnel when vehicle volumes exceed the capacity of I-70. When back-ups occur, CDOT stops vehicles from entering the tunnel, allowing traffic to clear, before releasing more traffic into the tunnel.

After Sunday's test, CDOT, CSP and SPD will test its use again at the end of the year, during winter driving conditions. If data from the additional tests are favorable, Rolling Speed Harmonization could be implemented during heavier traffic periods during some winter weekends in 2012.