Micro-Simulation Modeling of Traffic to Evaluate Two Congestion Relief Options: Roadway Widening and HOT Lane Direct Connections

摘要

How can traffic congestion in urban areas be relieved? The most traditional approach of simply adding more physical capacity is not always a realistic solution due to financial, environmental, social, political, physical roadway space or other constraints. However, enhancing the efficiency of the existing system can still make improvements to a certain degree depending on how efficient the existing system is. Often roadway congestion is not caused by the roadway segment where congestion is actually experienced, rather it is caused by bottlenecks downstream of that segment. In such situations, widening congested roadway segment serves only the purpose of storing more vehicles. Traffic operational improvements at the locations where the bottleneck exists may help reducing congestion by enhancing flow of traffic. This paper presents a case study (simulation model) that shows how freeway to freeway HOT lane connection through direct flyover ramps bring about more benefits compared to widening segments of a congested roadway by adding more than 25 lane miles. This simulation case study indicated that the widening option would reduce travel time by 15% whereas flyover ramps would provide 30% reduction in travel time along 15-mile segment of the corridor. The widening and flyover options increase throughput by 7% and 16%, respectively. This paper documents simulation model parameters, assumptions, and findings.