Work Zones as a Series of Bottlenecks: Developing a Methodology to Estimate Delay and Queue Length

Past studies on queue length and delay estimation have simplified work zones as a single bottleneck. This simplification may produce considerable error in queue length and delay estimations. In fact, there might be more than one bottleneck in a single work zone. The two main potential bottleneck locations are work space (WS) and transition area (TA). The objective of this paper is to develop a more accurate approach to predict queue length and delay considering that two bottleneck locations may exist in work zones. Shockwave theory is applied to study six conditions, each of which represents a relationship between demand and capacity at the bottlenecks. For the six conditions there are 21 queue propagation patterns, and some patterns are created due to the interaction between bottlenecks. Results from this approach were validated using field data.