Authors: Gang-Len Chang & K.P. Kang
Date: July 2008
To improve traffic mobility and safety in highway work zones, this study has focused mainly on developing advanced merge and speed control strategies, including both their individual and integrated control algorithms. Based on the deficiencies and limitations of existing work zone control operations, this research has made contributions mainly on the following four regards:(1) understanding traffic flow characteristics under work zone traffic conditions with empirical data and identifying their interrelations; (2) developing an operational model for computing the optimal set of thresholds for DLM and its implementation algorithm; (3) Proposing an optimal speed limit control model that can maximize the throughput of a lane-closure highway segment with a set of dynamically adjusted speed limits; and (4) constructing an integrated operational algorithm to take the advantage of the strengths of DLM and VSL controls. The simulation results have demonstrated that the developed DLM and VSL controls have better performance in terms of traffic mobility and safety than their existing controls based on static approaches, and also shown that the proposed integrated control of the DLM and VSL control has more promising properties than each individual control.