The capacity of highways between intersections

The capacity of a highway may be described as its ability to accommodate traffic, but the term has been interpreted in many ways by different authorities. Capacity has been defined as the flow which produces a minimum acceptable journey speed and also as the maximum traffic volume for comfortable free-flow conditions. Both these are practical capacities while the Highway Capacity Manual1 defines capacity as the maximum hourly rate at which persons or vehicles can reasonably be expected to traverse a point or uniform section of a lane or roadway during a given time period under prevailing roadway, traffic and control conditions. The time period used in most capacity analysis is 15 minutes which is considered to be the shortest interval during which stable flow exists.