In a recent episode of the Talking Michigan Transportation podcast, AASHTO Director of Safety and Mobility Larry Dwyer and Colorado Department of Transportation Deputy Director of Traffic and Safety Angie Drumm offered insights on ramp metering in a two-part series with host Jeff Cranson, Michigan Department of Transportation director of public affairs.
Michigan has reintroduced ramp metering on I-96 in Oakland County—a traffic management strategy that uses signals on freeway on-ramps to regulate the flow of vehicles entering the highway. While Drumm highlighted Denver’s long-standing and successful use of ramp metering, Dwyer offered a national perspective on how the strategy is applied across the country since the 1960s.
“My take on ramp metering is it’s a traffic management strategy,” said Dwyer. “Ramp metering produces several proven benefits. One, it reduces freeway congestion by spacing out the vehicle entry to the highway. It improves bottlenecks and freeway speeds by improving the traffic flow, rear-end collisions and merging collisions and you also have less stop-and-go traffic which can lead to these collisions and more kind of steady, free-flowing traffic. It also improves travel time reliability and increases the overall freeway capacity.”
Dwyer stressed that ramp metering is a proven strategy that improves traffic flow by reducing travel times. More than 20 states and major metro areas like Los Angeles, Seattle, Atlanta, and Chicago are utilizing ramp metering due to its effectiveness in easing congestion and enhancing safety. In addition to traffic relief, the podcast guests stressed significant safety improvements and environmental gains through reduced idling.
“Travel times can be reduced up to 48 percent and freeway speeds increased up to 62 percent, and then it has the added bonus of also reducing fuel use, and emissions are also reduced,” said Dwyer.
In addition to the United States, ramp metering is used all around the world. Dwyer noted that countries like Australia, Germany, Sweden, the UK, and Canada use ramp metering as part of their intelligent transportation systems. Cities like Melbourne and Sydney have advanced systems integrated with dynamic speed limits and real-time monitoring, leading to improved traffic flow and more accurate travel time information.
With new innovations continuing on the horizon, this podcast shined a spotlight on how ramp metering can be used moving forward.
Click here to listen to the full podcast.
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