Effect of Speed Limit Compliance on Roadway Capacity of Indian Expressways

Expressway is an arterial highway for motorized traffic, with divided carriageways for high speed travel, with full control of access and usually, provided with grade separators at location of intersections. Higher design speeds, restriction on slow moving vehicles, varied traffic composition with high amount of cars and no strict lane-discipline characterize these roads. This study aims to evaluate the change in roadway capacity with increasing driver compliance levels within a posted speed limit. It has been found that with increasing driver compliance level for a given posted speed limit there is an increase in roadway capacity along with a marginal decrease in the travel times at flow levels nearing capacity. The results of the study may be useful in underlining the importance of driver compliance to a designed speed limit along with its enforcement.