Validation of HCM Pedestrian Delay Model for Interrupted Facilities

The Highway Capacity Manual (HCM) 2000 equation for pedestrian delay at signalized intersections assumes that pedestrian arrivals at those intersections are random. However, if a significant percentage of those pedestrians are arriving from an upstream coordinated signal, the arrival rate may not be random and the average delay may be quite different from that which would be predicted. Two studies were conducted to test the HCM model for pedestrian delay at coordinated signalized intersections. Data collected at six intersections in St. Louis indicated that pedestrian arrivals at these locations were significantly affected by upstream signals. A study of delays along an arterial in Columbia, Mo. showed that 24 out of 30 data sets had delays that were significantly different from those expected from the HCM 2000 delay equations. 29 of the 30 data sets had variances of delay significantly lower than expected if arrivals were random. The results from these studies indicate that delay calculations for signalized intersections in coordinated systems should recognize the effect of signal coordination.