A computer program has been written which simulates the traffic at an urban intersection and determines both delays and fuel consumption of vehicles passing through the intersection. By placing typical unit costs on hours of time and gallons of fuel, operating costs are determined for each vehicle and then averaged for all vehicles travelling on each of the two streets. The variable inputs to the program include type of intersection control (two-way stop or semi-traffic-actuated signal), volume levels, turning percentages, critical lag at the stop sign or signal phrasing and detector locations for the traffic signal, sampling time, and vehicle fuel consumption characteristics. The program is written for an IBM 704-709 computer and has an approximate realtime to computer time ratio of four to one. To illustrate the use fullness of the program in the economic analysis of intersections, the program was run at various combinations of main street and side street volumes under both traffic signal and stop sign control. The cost contours for each type of intersection control were compared to find areas where stop sign control resulted in the lowest operating costs, where traffic signal control was cheapest and where the two types of control resulted in equal operating costs. The line of equal operating costs can be considered a warrant line separating traffic signal preferability from stop sign preferability.
Samenvatting