The research aims at exploring the usage of hard shoulder for congestion caused by an accident. The hard shoulders could be applied as a managed lane to release the congestion or as a bypass for emergency vehicles. To compare benefits brought by the different hard shoulder functions, criteria related to the congestion effect and rescuing efficiency during accidents are analyzed. The arriving and departing curve is used to analyze the congestion time, queue length and other congestion characters. The velocities of emergency vehicle at each time step would be predicted and the travel time of the emergency vehicles could be calculated. The travel time of the emergency vehicle to reach the accident location are used to represent the rescuing efficiency with different hard shoulder functions. The analyzing results shows that, the congestion would be much severer with the hard shoulder function as the emergency bypass compared to the function as the additional lane, while the efficiency of the accident handling would be slightly better. The benefit brought by the additional lane would be distinct with the increasing capacity. Meanwhile, a timely handle of the accident is critical for the public concerning and the mitigation of the congesting impact. For a comprehensive consideration, it is recommended that after the rescuing vehicles have arrived the accident location, the hard shoulder could be used as additional lane to release the congestion. The mobility could be increased for the proper use of hard shoulder.

CICTP