BY FREDA MIKLIN
Last month, officials of the Colorado Department of Transportation (CDOT) presented a pilot project designed to significantly lessen traffic back-ups on I-25 to the Greenwood Village City Council. Called the Smart 25 Managed Motorways plan (Smart 25), its purpose is to “improve travel time, reliability, and speed performance on I-25,” as well as minimize the cost of deployment of the system. If it works as expected, its impact on traffic will be equivalent to having added an entire new lane to I-25.
The work on this effort began in 2016, when a 14-mile span on I-25, consisting of 14 highway exits, was selected to conduct the pilot project. The area goes from University Blvd. on the north to RidgeGate Parkway on the south. Problems in procurement, followed by the pandemic, delayed construction. In addition to those I-25 highway exists, the project will also include freeway to freeway system ramps on I-225, C-470 and E-470 because they connect to I-25 in the project area.
Scott Pitera of WSP, a transportation operations consultant to CDOT, explained that Smart 25 will employ ramp metering technology that responds to actual traffic conditions (volumes, speeds, etc.) in real time to manage traffic on I-25. Originating in Australia, this is the first installation in North America. This “intelligent system optimizes flow along the entire route by using algorithms to resolve complex traffic problems” so as to prevent congestion. The data from all system entry ramps in the project is coordinated so that the ramp meters “talk to each other” to “balance queues and wait times” to most efficiently “utilize ramp storage across the system” simultaneously.
Although all entry ramps will have traffic-light type signals, they will only go on when they are needed based on traffic volumes. The signals will receive and process data from all the other ramps in the system that will cause them to change their timing based on actual conditions every 20 seconds.
The most significant costs of the project consisted of the installation of 40 new highly-detailed vehicle detectors. All costs were paid by CDOT.
When this system was employed in the M-1 Motorway in Melbourne, Australia in an area that is similar to the I-25 corridor, it “increased throughput by over 25 percent, which is the same as adding an additional lane of traffic for a very, very small fraction of the cost. They were able to improve speeds drastically, improve reliability because they prevented bottlenecks from forming, and very importantly, they were able to prevent back-ups onto arterial adjacent roadways,” according to Pitera’s PowerPoint presentation.
The plan, which began in June, is to collect data for three months on the existing CDOT system, then employ the pilot demonstration system for six months, followed by a performance evaluation report and stakeholder workshop. Pitera made clear that if anything goes awry during the pilot, it will be seamless to fallback to the existing CDOT system. There will be a “soft launch” of the system in August and it will become fully operational in October.
CDOT staff overseeing this effort are Zach Miller, project manager, who can be reached at firstname.lastname@example.org, 720-382-6381 and Steve Sherman, resident engineer, at email@example.com, 720-341-1895. The project website for this program is: https://www.codot.gov/projects/smart25pilotproject.
After the presentation, GV Mayor Pro Tem Dave Kerber, told Pitera, Miller, and Paul Jesatis, CDOT region one transportation director, that because, “We don’t know if people are going to be coming back to work in the Tech Center here…I would suggest…that any data you take isn’t going to be right…It’s not going to be normal conditions…You waited five years already. If you’d wait six years, at least we’d get a chance to get some normal situations.”
Councilmember Donna Johnston wanted to know, “How long will someone be waiting on Orchard to get on I-25 if there is perhaps more important roads that are backed up? I mean, would we suffer perhaps on Orchard Road waiting because there’s more of a back-up, up the road? Is that factored in somehow?” Pitera responded, “The number of lanes on each ramp and the length of those lanes and the total storage of each ramp, they’re very different throughout the corridor. That’s something that we’ve measured as part of the system…The way that the system works is that they try and balance wait times throughout the whole corridor…The system adjusts every 20 seconds.”
Councilmember Judy Hilton added, “The speed that people travel on I-225, then merging into I-25, then you add in the afternoon sun in your face, it’s just something to keep in mind, I know it’s not a part of this study, but it’s something that we ought to be mindful of because it’s a problem.”