Driving Speed Behavior of Cars and Trucks on Six-Lane Highway Work Zone Considering Lane and Location Deviation

Work zones are not only traffic bottlenecks, but also critical points for the safety of both vehicle occupants and workers. Vehicle speed is a key factor to estimate traffic efficiency and understand safety in work zones. However, the knowledge about how the speed of cars and trucks changes on different lanes in the work zone environment is limited. In this paper, the authors report on a study about the driving behavior and speed changes in a work zone environment considering the lane and location deviation. A typical 6-lane highway segment in Shanghai, China has been selected to collect data by seven (7) digital cameras along the work zone. Free flow speeds of 50 passenger cars and trucks on each lane at each data collection section have been extracted from the videos manually. The statistical analysis shows that vehicles’ compliance with the temporary speed limit is extremely low because the speed limit is much lower than desired/possible speed. Speed deviation caused by vehicle type, lane and distance upstream to the work is evident, which indicates a considerable error if studying work zone speed behavior with these three factors ignored. The authors find that the change of speed along the work zone can be divided into two stages (a constant stage and a linear deceleration stage), and a linear regression model for free flow speed prediction of cars and trucks is developed based on normal section speed, lane and location with different distance to work zone.