Behavior of vehicles along roads for which passing is not permitted

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