Known in the UK & Europe as ‘smart’ or ‘managed motorways’, Colorado is introducing a system of lane-specific variable message signage to improve traffic flow and safety on US 36.
This week, the Colorado Department of Transportation (CDOT) started field testing its Smart Signs system on US 36, between Federal Boulevard in Westminster and Table Mesa Drive in Boulder. The overhead signs, which have been tested behind the scenes for the last year, will help drivers anticipate and prepare for congestion and lane closures caused by accidents, disabled vehicles and other obstacles. The testing period began on Monday, July 18, and continues through to Friday, July 22. During this period, the traveling public has been provided with real-time incident information, with CDOT observing driver behavior when the signs were activated.
US 36 is one of two corridors in Colorado to have this system. The Smart Signs also will be implemented on southbound Interstate 25 from 120th Avenue to US 36, as part of the North I-25 Express Lanes. The Smart Signs system uses input from cameras and vehicle detectors to collect and process information about current traffic conditions, 24 hours a day. Information is then posted on the overhead gantry-mounted digital signs, displaying whether a lane is open or closed, or provide advisory speed limits to avoid the need for sudden braking that can lead to secondary accidents.
In all deployments of the technology, advisory speed limits will be used to incrementally slow drivers as they approach congestion. The lowest advisory speed will be 35mph (56km/h), even if traffic is moving slower. Just like a static speed limit sign, adverse traffic conditions may require slower speeds than the posted limit. If a lane is closed, the status signs will direct drivers to merge into an open lane in advance of the closure. Full-time activation of the US 36 Smart Signs system is expected to begin within the next several months. CDOT’s Smart Signs system is a component of the multi-modal US 36 Express Lanes Project. The scheme offers users the choice to ride the bus, carpool, bike, use the two free reconstructed general-purpose lanes, or pay a toll in the Express Lanes, which accommodate high occupancy vehicles (HOV), Bus Rapid Transit (BRT) and tolled vehicles.
“For years, CDOT has studied similar traffic management systems in other states. We took the best practices of those states and are applying those to our highways,” explained CDOT’s transportation systems management and operations director, Ryan Rice. “This is the first time a system like this has been installed in the state, and we anticipate it’ll improve safety on the corridor by allowing drivers to be better prepared for problems ahead. In other states where similar traffic management systems have been employed, crashes have been reduced by an average of 30% and the road capacity has increased approximately 22%.”