Samenvatting
An instrumented vehicle traversed a straight, level section of rural two-lane, two-way road near Sydney at fixed speeds of 20 and 30 m.p.h. Because of the fairly long queues which developed behind this vehicle, it was possible to find the average number of vehicles which would overtake for any given size of headway in the opposing traffic. Hence, maximum rates at which vehicles can overtake slow vehicles are calculated as a function of the opposing flow and extended to the study of the two-directional "capacity" of the road in the neighbourhood of the slow vehicle. The rate at which traffic catches the slow vehicle is compared with the rate at which the traffic can overtake the vehicle.