The Maine DOT updated its variable speed limit (VSL) system to include travel time information on Interstates (I-95 and I-295) and surrounding arterials for $776,850.

A review of rural travel time information systems in the United States

Made Public Date


I-295 and I-95 statewide
United States

Summary Information

This report discussed current and emerging technologies used to detect travel times and improve traffic management on rural roadways. A broad range of technologies were reviewed including Bluetooth, toll tag readers, in-pavement magnetic detectors, automatic license plate readers (ALPR), machine vision systems, radar/microwave/LIDAR systems, inductive loops, crowdsourcing, and cell phone signal monitoring systems.

The following system costs were drawn from a case study of a deployment in 2008 and 2009 where the State of Maine updated its variable speed limit (VSL) sign system on Interstates I-95 and I-295, and surrounding arterial routes. The State’s intention was not just to capture data related to user delay and implement VSL based on prevailing roadway conditions, but to provide motorists with real-time travel time information.

The VSL system was not part of an integrated system, but it used a tiered approach that involved radar, camera, and dispatcher information to verify incidents and reinforce traffic management decisions for the corridor.

Costs for this basic but informative way to share travel information was much less than typical deployments that use DMS and associated hardware, software, and technology packages. The VSL project cost in Maine was estimated at $776,849.54.

Travel Time on Arterials and Rural Highways: State-of-the-Practice Synthesis on Rural Data Collection Technology

Travel Time on Arterials and Rural Highways: State-of-the-Practice Synthesis on Rural Data Collection Technology
Publication Sort Date
Singer, Jeremiah (Westat), et al.
U.S. DOT Federal Highway Administration

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System Cost

Rural interstate highway travel time information system: $777K.