The objective of the I-95 Corridor Coalition’s Vehicle Probe Project is to create a seamless traffic monitoring system that spans the eastern seaboard delivering travel times and speeds on freeways and arterials using probe technology. Data from various sources are fused to present a comprehensive picture of traffic flow. Member agencies have found numerous uses for the data beyond simply travel information, which was the original use at the project inception.
Currently, there are 19 agencies which have access to vehicle probe data. Several agencies are using the Vehicle Probe Project (VPP) data to support their 511 web and phone service. Some agencies use the vehicle probe data to calculate travel times and post them on message signs. Performance measures and travel time reliability, particularly in congestion prone areas, are being calculated using real-time and archived VPP data. I-95 Corridor Coalition member agencies use the project monitoring site to observe traffic patterns within its boundaries, but especially across state lines to anticipate incidents and congestion. VPP data are also used as input for the Coalition’s long-distance trip planner website (www.i95travelinfo.net) and variable message signs to enhance traveler information.
Based on Coalition's experience, a publication entitled I-95 Corridor Coalition - Vehicle Probe Project General Benefits White Paper, August 2010 offers valuable guidance on the use of probe data in traffic management. Lessons learned are identified and presented below.
The Vehicle Probe Project (VPP) has been providing data the member agencies since 2008. The agencies have recognized the benefits of VPP data to their respective departments of transportation, traffic management centers, and the public they serve. Lessons learned from the experience of several state departments of transportation (DOT) include the following:
- Enhance incident management efficiency by using vehicle probe data (New Jersey). During a surprise snowstorm in October 2008, the New Jersey Department of Transportation (NJDOT) Traffic Operations Center was reviewing an accident on I-80 via a closed circuit television (CCTV) camera. The VPP monitoring site identified a second incident where CCTV coverage was not available that involved multiple jack-knifed tractor-trailers along I-80. The knowledge gained from the VPP about the second incident enabled responders to attend to the second incident by as much as an hour than what would be possible without the VPP. An NJDOT executive stated at the 2008 ITS World Congress and ITS America Annual Joint Meeting that the expedited response to the second incident translated into an estimated $100,000 savings in user delay costs.
- Use vehicle probe data for cost effective traffic monitoring (North Carolina and South Carolina). The North Carolina DOT has noted its more effective utilization of traffic monitoring budget by using vehicle probes in order to increase needed coverage. With typical remote traffic microwave sensors (RTMS), costs of equipment, installation, and maintenance were approximately $48,600 per mile. In contrast, the vehicle probes save money by replacing the RTMS at about a quarter of the cost. Similarly, the South Carolina DOT also cited the agency’s reduction in its use of side fire radar detectors in favor of using vehicle probes. Maintaining its radar coverage over 300 miles is equal to the total cost of the vehicle probe data covering 1,200 miles with the added benefit of transmitting travel time data in addition to speed data.
- Consider using vehicle probes as a reliable means to calculate travel time. Three I-95 Corridor Coalition member agencies—Maryland, North Carolina and South Carolina—have used the VPP as their primary data source to calculate and present travel times on variable message signs and traveler information websites. Maryland programmed the implementation of travel times for the year 2012, but was able to advance the implementation by two full years as a direct result of data availability. Similarly, South Carolina and North Carolina each were able to deploy travel times on message signs as a result of having statewide coverage through the VPP. Both the cost and convenience of ubiquitous coverage without roadside intrusion were factors in the success of these agencies’ respective deployments.
- Use vehicle probe data to assist police proactively manage potential traffic queue ups (New York). Significant delays have been observed along Interstate 87 (I-87) approaching Woodbury Commons Shopping Complex on Thanksgiving evening and the following day (Black Friday) as shoppers caused back-ups along I-87 between the Shopping Complex access and I-287. In 2009, the New York State (NYS) Police used the data provided by the I-95 Corridor Travel Time website, along with data from the New York 511 website to assist in managing traffic congestion in the area. A NYS Police surgeon was aware of the VPP data through his involvement with the I-95 Corridor Coalition’s Incident Management Program Track. With assistance from the NYSDOT transportation management center (TMC) operators and NYS Thruway Authority staff, the NYS police were able to look at the trouble areas and determine if/when to implement changes such as closure of full parking lots, ramp closures to prevent backups onto the freeway, and activation of advance variable message sign (VMS) messages to alert motorists of the changes ahead. Using this data, the police were able to reduce by half the traffic queues experienced in other years. In addition, the I-95 Corridor Travel Time and New York 511 websites helped to conserve State Police resources by identifying issues on the website before dispatching state troopers to the scene.
The VPP has fostered cooperation among the I-95 Corridor Coalition member-agencies. As a result, VPP data have been useful to various state DOTs and TMCs in their efforts to manage traffic efficiently within the state as well as across state jurisdictional lines. The Coalition members that are using the VPP data have also reported accruing benefits by saving money, improving travel time, reducing delay and decreasing driver frustration.