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Ray Starr

Minnesota Guidestar Program and Project Updates

Presentation by Ray Starr, Assistant State Traffic Engineer (ITS), Minnesota Department of Transportation

September 13, 2005

The first Advanced Transportation Technologies Seminar of 2005 featured Assistant State Traffic Engineer Ray Starr presenting highlights of several ITS-related projects under Mn/DOT's Guidestar program. Formed in 1991, Guidestar is a statewide initiative, charged with research and implementation of ITS technologies on urban and rural roads throughout Minnesota.

Starr's presentation focused on three research projects that characterize the diversity of intelligent transportation systems:

  • Exploring the potential benefits of giving large commercial trucks signal priority at highway intersections;
  • Monitoring and disseminating information on traffic and road conditions via the Condition Acquisition and Reporting System (CARS) and 511 traveler information service; and,
  • Integrating emergency reports from in-vehicle systems (such as General Motors' OnStar™) with emergency services dispatch.

Starr explained the reasoning behind Mn/DOT's interest in the effects of signal priority for large trucks. Because trucks are slower to accelerate than passenger cars, they experience a larger delay when they stop at a signal; these delays are passed on to any other vehicles that are trapped behind a truck. In addition, Starr said, stopping trucks leads to more pavement damage, and greater noise impacts on surrounding areas.

To investigate ways of reducing these unwanted effects, researchers selected a stretch of four-lane highway with several independently controlled traffic signals, and performed computer modeling. Three possible techniques were investigated: optimizing signal timing; holding green signals longer for approaching trucks; and using variable message signs to notify trucks of the speed required to pass through a green light—a technique known as the "speed funnel."

Although the cost of implementing truck priority is relatively low, Starr said, the negative effects of the various techniques proved to outweigh or cancel out the positives. However, Starr continued, the possibility that results on a two-lane highway segment might be different could justify further research.

Starr then went on to give an overview of the statewide Condition Acquisition and Reporting System (CARS), which supports the Minnesota 511 traveler information network. CARS integrates multiple data sources, including Road/Weather Information System monitoring stations, traffic detectors, and construction information, to provide real-time traveler information to the 511 telephone service and Web site. The system continues to develop, Starr said, with plans for include greater integration with other states along the I-90/I-94 "Northwest Passage" from Chicago to Seattle.

Data integration was also the theme of the final project Starr presented: dubbed the "Mayday" project, its goal is to integrate emergency voice and data communications between in-vehicle assistance systems like GM's OnStar with emergency call centers and responders. OnStar and similar systems can notify a commercial call center if sensors detect sudden velocity changes, airbag deployment, or similar signs of an accident; the service provider is then charged with notifying emergency services. The Mayday Project would streamline and partially automate this system, and provide data directly to emergency services through a central standardized database in which any in-vehicle telematics provider could participate. Initial testing, Starr said, has provided anecdotal evidence that the system could improve response times.