Impact Assessment of Short-Term Work Zones on Intersection Capacity in New York City

New York City infrastructure is one of the oldest transportation infrastructures in the United States. Local street construction and short-term work zones are almost continuously planned events that affect the movement of traffic on city streets by requiring the closing of one or more lanes at intersections throughout NYC, and it is important to understand the effect on capacity due to such work. This paper looks at the effect of short-term work zones on the capacity of signalized intersections in New York City. Data was collected at five locations in New York City, both during the work zone and then again after the work zone was removed. Over 25 hours of video data was collected and reduced. It was found that at all locations, the saturation headway was smaller during the work zone compared to after the work zone was removed, that is, the saturation flow rate per lane increased during the work zone. This was an unexpected result. A possible reason for this is the increased traffic pressure that drivers feel when a lane is closed. Thus, although overall approach capacity does decrease because a lane is closed, it did not decrease as much as expected. The field values are then compared with those from two other models: the Highway Capacity Manual model and a model developed by Schroeder et al. It was found that both models underestimate the capacity of the approach.