Colorado’s I-70 Express Lane shows benefits during first season


Agencies and road users are hailing the success of the Colorado Department of Transportation’s (CDOT) new tolled Express Lane on the I-70 Mountain Corridor, which has seen its first winter season of operation.

Last summer, CDOT and its High Performance Transportation Enterprise (HPTE) division opened Express Lanes on the I-70 Mountain Corridor, US 36 and on North I-25, with the goal that they would deliver more consistent, faster speeds and reduced travel times for all lanes, including general purpose lanes, along their corridors. All the new Express Lanes are showing improvement in traffic congestion, and mountain drivers are getting relief since the I-70 Mountain Express Lane opened mid-December 2015.

The 13-mile eastbound Express Lane runs from Empire through Idaho Springs, and is open during high traffic volume times, such as holidays and weekends, for a total of 73 days per year. When the Express Lane is not open, roadway signage indicates it is now closed and is used as a shoulder for emergency purposes. CDOT figures show that the I-70 Express Lane’s first season delivered benefits to all eastbound travelers, across all lanes.

The Express Lane is expected to be closed on weekends until Memorial Day, when the summer traffic resumes. Historically, the summer season has more traffic and for longer hours of the day than the winter season, and summer traffic also has more trailers and recreational vehicles in the corridor, which are not permitted in the Express Lane.

As an example of the improvements so far, CDOT cites April 3, when 34,136 vehicles traveled the corridor during the 11 hours the Express Lane was open, averaging 3,103 vehicles per hour (VPH). Prior to the Express Lane, the corridor would have dropped to stop-and-go traffic when a rate of 3,100VPH was reached. This year, during the peak hour, from 3-4pm, travel speeds were just below 55mph (88km/h) in the Express Lane and 40mph (64km/h) in the general purpose lanes, which shows a significant improvement in travel times for all lanes.

A summary of the I-70 Mountain Express Lane’s first winter season shows throughput increased by 15%, as the corridor had 1.03 million vehicles compared to 2010-2012 average of 896,000 vehicles, with the Express Lane taking 42,600 vehicles (4%). Peak hour travel speeds stayed above 45mph (72km/h) in the Express Lane and above 35mph (56km/h) in the General Purpose (GP) lanes throughout the season. During peak periods, the GP Lanes travel times improved by 18% and vehicles in the Express Lane were able to travel at the speed limit. Travel times fell from a 2013-2015 peak hour seasonal average of 16.5 mins (44mph) to Express Lane average of 12 mins (60mph) and 13.6 mins (53mph) for GP lanes. Corridor incidents were down by 15% with 23 total incidents. There was an average of 22 mins between an incident being reported and cleared, with the time to clear corridor back-ups substantially improved.

“Population numbers in Colorado are rising rapidly,” said David Spector, HPTE director. “We can no longer build our way out of congestion, we have to implement innovative solutions, like Express Lanes. During this winter season, all users of the corridor noticed the benefits of the Express Lane. Not only did they see reduced travel times, but fewer incidents as well.”

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Tom has edited Traffic Technology International (TTi) magazine and its Traffic Technology Today website since May 2014. During his time at the title, he has interviewed some of the top transportation chiefs at public agencies around the world as well as CEOs of leading multinationals and ground-breaking start-ups. Tom's earlier career saw him working on some the UK's leading consumer magazine titles. He has a law degree from the London School of Economics (LSE).