News

I-70 Speed Harmonization Begins Sunday

December 16, 2011 - Central Eastern Colorado/CDOT Region 1 - Program extended to bottom of Floyd Hill.

SUMMIT/CLEAR CREEK COUNTIES – The Colorado Department of Transportation (CDOT), in coordination with the Colorado State Patrol (CSP), Silverthorne Police Department (SPD), Clear Creek County Sheriff (CCCS), and Idaho Springs Police Department (ISPD), will begin the winter season implementation of Rolling Speed Harmonization this weekend.  It will run on eastbound Interstate 70, from Silverthorne to Floyd Hill.

Beginning sometime between 11 a.m. and noon, on Sunday, December 18, 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 then will pace eastbound vehicles, at speeds between 45 and 55 mph, to the entrance of the Eisenhower/Johnson Memorial Tunnel (EJMT).

The SPD then will hand-off to the CSP inside the tunnel, with the CSP pacing vehicles through the EJMT and east to Georgetown.  At that point, the CCCS will take over, pacing vehicles to Downieville, with the ISPD continuing the operation to the U.S. 6 junction, at the bottom of Floyd Hill, where eastbound I-70 expands to three lanes.

A new pace group is expected to leave Silverthorne about every five to 10 minutes, with operations continuing along the 39-mile segment through mid-afternoon,

Implementation follows two previous tests of the program – on Saturday, August 13, from Silverthorne to the EJMT, and Sunday, September 25, from Silverthorne to Empire Junction.  Data collected from those tests indicated Rolling Speed Harmonization created more uniform vehicle speeds, helping to improve safety, reduce traffic crashes and improve traffic flow on the corridor.  It also showed very high compliance and that speed differentials were reduced, even between vehicle groupings – a key determinant since wide variations in speed lead to higher probability of accidents which, in turn, substantially increases congestion.

“Given the successful tests we had earlier this year, we wanted to take this opportunity to run harmonization before the anticipated higher traffic volumes during the upcoming holidays and weekends,” said CDOT Regional Transportation Director Tony DeVito.  “Using it is a temporary measure but it’ll verify that this tool can be operated in varying road and weather conditions. We’ll continue to monitor and evaluate the program for any necessary improvements.  We’re also using it as a way to reduce the need to meter at the tunnel.”

Eastbound traffic is held or “metered” 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.

CDOT supports the program by paying 24 off-duty officers overtime, at an approximate cost of  $4,500 to $5,000.

After Sunday’s operation, CDOT resumes Rolling Speed Harmonization on Sunday, January 1.  It is scheduled to continue on Sundays or Mondays (Martin Luther King Jr. Day/President’s Day) through the 2012 ski season.

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