Simulation studies of traffic management strategies for a long tunnel

The Hsueh-Shan Tunnel, the fifth long tunnel in the world, has a total distance of 12.9 km. After the opening of the tunnel, traffic demand between Taipei and I-Lan increased dramatically. However, efficient traffic management strategies for the Hsueh-Shan Tunnel need to be developed and evaluated accordingly in order to alleviate traffic congestion due to high demand and/or possible incidents. The research aims to evaluate possible traffic management strategies based on available control devices through simulation-assignment techniques. Possible traffic management strategies, including access control (ramp metering), lane control and route guidance, are proposed and examined through numerical experiments. In order to analyze traffic management strategies based on simulation, DynaTAIWAN, a simulation-assignment model, is developed to simulate traffic control strategies and reflect driver’s response to route guidance. Several indexes, including vehicle queue length, average density and average speed, are used in the comparisons. The results show that ramp control provides the best benefits compared to other strategies and can reduce the average queue length by about 18%.

► Traffic management strategies relieve incident impact through shortening incident duration.
► Access control (ramp control) is the most efficient strategy during incidents.
► The benefit of VMS is not significant due to limited alternative routes in this traffic network.