Abstract
The flow of traffic on roads for which passing is not permitted is studied. Such traffic conditions exist in rural areas, hilly or mountainous regions, tunnels, etc. The traffic flow process is considered as taking place in one directional road of infinite length, with passing not permitted. Measures of traffic flow in a road where vehicles have one or two free speeds are studied. Measures of traffic flow are obtained for general vehicle entrance processes and derived explicitly for the homogeneous Poisson case.