Actively Monitor Equipment in Dilemma Zone Protection Systems to Ensure Continued Functionality and Interconnectivity.
Integrated Intelligent Intersection Control System Implemented on the I-95 corridor in Maryland Led to Lessons Learned.
Maryland, United States
The Dilemma Zone Protection System
Summary Information
When approaching signalized intersections, dilemma zones leave drivers unsure of whether it is safe to stop or proceed, at the onset of a yellow light. This hesitation poses greatly increased risk for collisions. This study summarized a research project that developed and implemented the Integrated Intelligent Intersection Control System (III-CS) tool on Maryland’s Interstate 95 corridor. The III-CS was built on concepts implemented in Maryland’s existing Dilemma Zone Protection System (DZPS), involving wide-range vehicle sensors to track speed profiles of vehicles in the 600 to 1,000-foot range. This provided Signal Phase and Timing (SPaT) data to in-cabinet computer, adjusting intersection light timing to maximize safety, allowing green-light extension or termination.
- Actively monitor equipment in dilemma zone protection systems to ensure continued functionality and interconnectivity. This study mentioned that, as crashes are mostly random events, it would be possible for some sensor or signal controller outage to go undetected. This could be prevented by actively monitoring the continued functionality and interconnectivity of all the equipment (e.g., in-cabinet computer sends information to its control center on each run red-light to facilitate system monitoring).
- Consider selecting a site with the highest potential for benefiting from the implemented technology. This study recommended that the benefits of III-CS would be highest in high-speed areas with relatively low congestion, such as rural intersections, although any physical design challenges could complicate measures intended to reduce collision rates.
- Provide training for operators looking to use the III-CS technology. This study pointed out that, while sophisticated in design, the III-CS was built to be user friendly. Training video that provided instructions to the operators in connecting and calibrating the tool to a given intersection was created.
