The term intelligent transportation systems (ITS) encompasses a broad range of communications-based information technologies used by the transportation industry to improve traveler safety and traffic flow. Its applications to highways involve collecting traffic performance data (speed, volume, travel time, queues), delivering driver information, as well as directing use of freeway lanes or in the case of arterials, adjusting traffic signal settings at intersections. Data is collected using ITS field devices along arterials and highways. These are then analyzed to be used for traveler information such as presence of congestion or accidents ahead, and travel time between two locations, so drivers know what can be expected at the next turn of the road or even before beginning their trip.
ITS is being employed in southern New Jersey as a traffic mitigation tool to enhance traffic safety and operations during construction of the U.S. Route 295 / Route 42 / Interstate I-76 (Interchange) Direct Connection project. This interchange serves as a gateway for travel to and from Philadelphia and Camden by people who live in this part of New Jersey. It has had a poor crash history due in part because its outdated design is no longer capable of safely accommodating over 250,000 vehicles per day. Keeping traffic flowing in a safe and efficient manner is a critical project objective and a New Jersey Department of Transportation (NJDOT) commitment. Although the NJDOT has an established ITS network statewide, its architecture in southern New Jersey still needs to expand to meet increasing driver and commuter needs. The ITS component of the Direct Connection project will expand these capabilities significantly, giving NJDOT the resources to keep regional networks operating at an acceptable level of service during and after project construction.
The concept of fast-tracking the Advance ITS Contract so that ITS elements can be used to mitigate construction traffic impacts was employed by the NJDOT offices of Project Management, ITS Engineering, and Traffic Operations, as well as the Federal Highway Administration (FHWA). By working closely with NJDOT and FHWA, Dewberry was able to prepare contract-ready plans that were designed, advertised and bid before any of the major roadway construction commenced.
Constructing the Direct Connection Interchange
Construction will occur in several stages. Each stage would require protecting and relocating existing communications conduit and fiber optic cable multiple times. To avoid this, we developed a proactive scheme to "redirect" communications. Temporary communication hubs were established to redirect ITS data from exiting fiber optic lines within the construction area to leased communications services at locations outside of the construction areas. Contractors would then be free to perform roadway work without concerning themselves with damaging or disrupting existing fiber optic communication systems and ITS devices.
This protected the functional integrity of the existing ITS devices along the three major routes entering the interchange. By supplementing the existing ITS devices with additional traffic monitoring, information and control strategies, the system will support a higher level of operational reliability serving traffic approaching and passing through the project area.
The additional ITS systems were selected based on possible incident scenarios in and around the construction area. This included parallel arterials of U.S. 130 and NJ 168 that will be forced to accommodate traffic surges if freeway diversions occur. To manage these spikes in arterial traffic flow when diversions from freeways occur and to manage them well, the latest in Adaptive Traffic Signal Control systems is being used to meet this need. Such Adaptive Signal systems do not require operator intervention to work and traffic signal timing adjustments are taken care of automatically based on actual, real-time demand.
Dynamic message signs (DMS) were added to help expand agency capabilities to disseminate traveler information including travel time information along segments of freeways. Travel time detectors were placed on the three major roadways entering the interchange to monitor travel on those roads and to provide more accurate travel times to destinations beyond the interchange. The additional DMS signage and travel time sensors installed under the Direct Connection project, will provide more timely and relevant information to drivers and allow them to make good driving decisions - whether they are within 20-30 miles of the construction project or within one mile from it. The travel time detectors will also monitor and collect traffic data on the signalized parallel arterials as a means of system verification and validation of the Adaptive Traffic Signal Control system.
Our schemes currently identify traffic incidents earlier, and mitigate their impacts quicker, than ever before.
Each of these ongoing additions help to alert drivers of major incidents – and potential alternate routes – as far ahead of the interchange area as possible. By choosing those alternate routes, drivers help to not only reduce congestion at interchange work areas, but also improve the safety of those areas for everyone involved.