Impact assessment of driver speed limit compliance behavior on macroscopic traffic characteristics under heterogeneous traffic environment

This study aims to evaluate the change in roadway capacity with increasing driver compliance levels for a given posted speed limit. The simulation experiment was conducted for all-cars traffic and varying traffic compositions on an eight-lane divided multi-lane urban road in Delhi, India. It is found that with increasing driver compliance level for a given posted speed limit, there is an increase in roadway capacity but with marginal increase in the critical speed of the traffic stream. Also, higher critical speeds are observed at very high and very low compliance levels. Furthermore, based on speed–flow plot developed from field observed conditions, the present compliance on selected multilane urban road at stream level is found as 40% approximately. The results of the study may be useful in underlining the importance of driver compliance with posted speed limit along with its enforcement for better safety.