Average Delay at Unsignalized Intersections for Periods with Variable Traffic Demand

For unsignalized intersections, the average delay suffered by drivers on minor approaches is treated as the parameter to characterize the quality of service. The current method, as it is used by guidelines around the world, has some shortcomings. It neglects the initial queue at the beginning of the interval for observation, and it cannot account for realistic conditions during the subsequent interval. Both aspects make existing delay equations useless to analyze a sequence of time intervals. A new delay equation for unsignalized intersections has been derived; it can include the effects of an initial queue and of variable capacities. With these characteristics, it can be applied if a longer series of time intervals (e.g., 1 day) is analyzed. As with all current approaches, the new equation is also an approximate solution. It was tested by exact numerical calculations and by simulations. By these comparisons, the new equation demonstrated quite a high performance.