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Citation |
Bonneson JA, McCoy PT. Transp. Res. Rec. 1993; 1421: 76-81. |
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Copyright |
(Copyright © 1993, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing) |
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DOI |
unavailable |
PMID |
unavailable |
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Abstract |
The design of the traffic detection scheme at an intersection can have a considerable impact on traffic safety and efficiency. A detector design (i.e., the detector layout and controller timing) that is not "tuned" to the geometrics of the intersection and its traffic demands can result in higher motorist delays than would be obtained with pretimed control. The detector design can also have an effect on safety. Designs that continually present the yellow signal to drivers when they are in the zone of indecision are likely to be associated with more accidents than designs that detect these drivers and extend the green signal for them until they are clear of the intersection. The safety and efficiency of a traffic detector design can be determined from the probability of max-out [a max-out occurs when the green is extended by a continuous stream of arrivals until the maximum green duration is reached (and a conflicting call is continuously held on one or more phases)] and the amount of time spent waiting for gap-out and subsequent phase change. A detector design that minimizes these measures of effectiveness should provide safe and efficient operation. Achieving the optimal combination of these measures can be difficult because of complex interactions among detector design elements (i.e., detector location, detector length, vehicle speed, passage time setting, and call-extension setting). The methodology described in this paper will allow the designer to determine the optimal combination of design elements in terms of safety (via infrequent max-out) and operations (via a short waiting time for phase change). Language: en |