Like it or loathe it, highways across the country are adopting dynamic tolling—also known as "congestion tolling" or "value tolling"—a system where toll prices are based on the number of vehicles on a specific road at a specific time. It works by encouraging discretionary rush-hour drivers to use roads and highways at off-peak times, thus alleviating peak traffic.
Studies show that drivers who have not experienced dynamic tolling may be initially resistant, but when they become familiar with dynamic tolling, they support it, as it offers a more predictable and shorter commute. By removing even 5 percent of the vehicles from a congested roadway, pricing enables the system to flow much more efficiently, allowing more cars to move through the same physical space.
In the past few years, there has been a surge in interest in congestion tolling across the country, with at least 12 states now using dynamic pricing on at least one tolled highway. They include California, Florida, Maryland, Texas and Virginia.
Around the world, Oslo, London, Singapore and Stockholm are all cities that have "congestion pricing" systems similar to those in place or planned for highways and cities in the United States.
How Congestion Tolling Works
With congestion pricing, toll prices typically vary by time of day and are collected at highway speeds using electronic toll collection technology. Traffic flows freely, and there are no toll booths. Vehicles are equipped with transponders, which are read by overhead antennas. Toll rates for different time periods may be set in advance, or they may be set dynamically, which means they may be increased or decreased every few minutes to ensure that the lanes are fully utilized without a breakdown in traffic flow.
Examples of Congestion Tolling in the U.S.
Dynamic tolling is becoming commonplace in many areas of the country. Here are some examples:
Since 1998, single-occupant vehicles pay a per-trip fee each time they use the I-15 High-Occupancy Vehicle (HOV) lanes. Tolls vary with the level of traffic demand on the lanes. Surveys show that commuters overwhelmingly support the HOV lanes.
In Northern Virginia, I-66 has introduced rush-hour, peak-direction, high-occupancy toll (HOT) lanes, which resulted in many drivers adjusting their travel patterns. The tolls are dynamic — meaning they change according to demand and volume of traffic to maintain an average vehicle speed of 55 mph. The tolls are calculated every six minutes.
In Fort Myers, Florida, a 50 percent discount on the toll was offered on the Midpoint and Cape Coral bridges for a short period of time before and after the rush hours. Among those eligible for the discount, there was an increase in traffic of as much as 20 percent during the discount period before the morning rush hours, with corresponding drops in the rush hour itself.
Oregon is testing a pricing scheme involving per-mile charges, which it will consider using as a replacement for fuel taxes in the future. A congestion pricing component is being tested, with higher charges during congested periods on high traffic road segments. The Puget Sound Regional Council has been testing the travel behavior impacts of a similar charging system in the Seattle metropolitan area during 2005-2006. Charges are based on the type of facility being used and its level of congestion.
New York City may be the first major city to ease traffic congestion by charging motorists a hefty toll for driving into its most crowded areas.