A forwarding system could prove beneficial as an addition to an electronic communication and control system that automatically modifies the switching of traffic lights to give priority to emergency vehicles. A system to which the forwarding system could be added could be any of a variety of emergency traffic signal preemption systems: these include systems now used in some municipalities as well as advanced developmental systems described in several NASA Tech Briefs articles in recent years.
Because of a variety of physical and design limitations, emergency traffic-signal-preemption systems now in use are often limited in range to only one intersection at a time: in a typical system, only the next, closest intersection is preempted for an emergency vehicle. Simulations of gridlock have shown that such systems offer minimal advantages and can even cause additional delays.
In analogy to what happens in fluid dynamics, the forwarding system insures that flow at a given location is sustained by guaranteeing downstream flow along the predicted route (typically a main artery) and intersecting routes (typically, side streets). In simplest terms, the forwarding system starts by taking note of any preemption issued by the preemption system to which it has been added. The forwarding system predicts which other intersections could be encountered by the emergency vehicle downstream of the newly preempted intersection. The system then forwards preemption triggers to those intersections.
Beyond affording a right of way for the emergency vehicle at every intersection that lies ahead along any likely route from the current position of the vehicle, the forwarding system also affords the benefit of clearing congested roads far ahead of the vehicle. In a metropolitan environment with heavy road traffic, forwarding of preemption triggers could greatly enhance the performance of a pre-existing preemption system.
This work was done by Aaron Bachelder of Caltech for NASA's Jet Propulsion Laboratory. For further information, access the Technical Support Package (TSP) free online at www.techbriefs.com/tsp under the Electronics/Computers category. In accordance with Public Law 96-517, the contractor has elected to retain title to this invention. Inquiries concerning rights for its commercial use should be addressed to:
Innovative Technology Assets Management
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4800 Oak Grove Drive
Pasadena, CA 91109-8099
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Refer to NPO-40492, volume and number of this NASA Tech Briefs issue, and the page number.
This Brief includes a Technical Support Package (TSP).
Long-Range Emergency Preemption of Traffic Lights
(reference NPO-40492) is currently available for download from the TSP library.
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Overview
The document is a Technical Support Package from NASA's Jet Propulsion Laboratory (JPL) detailing an innovative system for long-range emergency preemption of traffic lights, identified by the NPO-40492 designation. This technology addresses the limitations of traditional emergency traffic signal preemption systems, which often can only preempt one intersection at a time and are hindered by factors such as road terrain, weather, and optical trigger distances.
The proposed solution is an inexpensive add-on system that predictively forwards local intersection preemption triggers to downstream intersections. This capability allows for multiple intersections to be preempted in advance, thereby improving traffic flow and reducing congestion for emergency vehicles. The technology is particularly beneficial in metropolitan areas with heavy traffic, as it can clear congested roads ahead of an approaching emergency vehicle, enhancing the overall performance of existing preemption systems.
The document outlines the development status of the technology, indicating that a prototype has been developed and is undergoing testing, with an estimated time frame of 3-6 months to reach a commercial product. The innovation is not yet in use outside of JPL, and there are plans for future public disclosures regarding the technology.
The potential applications for this technology include use in automobiles and by emergency workers, making it relevant for both public safety and commercial markets. The document emphasizes the novelty of the system, which not only improves the efficiency of emergency response but also sustains local traffic flow, akin to principles in fluid dynamics.
In summary, this Technical Support Package presents a promising advancement in traffic management technology, aimed at enhancing emergency response capabilities through improved traffic signal preemption. The innovation represents a significant step forward in addressing the challenges faced by traditional systems, with the potential for widespread application in urban environments.
