Evaluating Capacity and Delay for Signalized Arterials with Freight Deliveries

Freight deliveries on signalized urban streets are known to cause lane blockages during delivery. Traffic congestion associated with urban freight deliveries has gained increasing attention recently as traffic engineers and planners are tasked with finding solutions to manage increasing demand more sustainably with limited road capacity. The goal of this research is to evaluate two models for quantifying the capacity and delay effects of a lane blocking freight delivery on a signalized urban street. The two methods are: an all-or-nothing model similar to methodology used in the Highway Capacity Manual 2010 (HCM2010) and a detailed analytical model consistent with kinematic wave theory. The purpose is to provide insight on the use of these tools for analysis of urban freight delivery policy. The results of the two models are compared with each. A simulation of 8th Avenue in New York has been calibrated to observed freight deliveries from a six-hour period, and the simulated results confirm effect of delivery location on capacity and delay. The results show that the methods from the HCM2010 to account for the effects of buses stopping for passengers provide only a coarse representation of the capacity and delay effects of urban freight deliveries. The more detailed approach that accounts for the dynamics of queuing provide closed form analytical formulas for delay and capacity that can account for varying locations of deliveries, long delivery durations, and different impacts on different lane groups.