Target Completion Date: February 29, 2008 Safety, Operations, and Traffic Engineering
Newer traffic signal control systems provide pre-emption for emergency vehicles by using advanced sensor and communication technologies. Pre-emption is widely used by transportation agencies, including Northern Virginia Smart Traffic Signal System (NVSTSS), to help emergency vehicles get to destinations quicker. A drawback is disruption of traffic flow, thus pre-emption strategies include a “recovery” algorithm that allows quick return to normal conditions to avoid major disruption. Changes in time-of-day traffic signal timing plans also cause flow disruption. As such, transition algorithms are embedded into the traffic controllers. Many “recovery” and transition algorithms are available but evaluating them in the field is unpredictable and unsafe, and field tests requiring evaluation data collection under various traffic conditions requires major time and effort. Research in a laboratory environment is needed to identify the best pre-emption and transition strategies.
Last updated: July 5, 2023
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