There is increasing demand for data on the number and type of vehicles traversing a given section of road, and on vehicle speeds. Such information is necessary for the development of traffic policies, for studies of road safety and for the planning of programmes of maintenance and new road construction. Techniques for obtaining these data have been developed. This paper describes the road sensors employed, and their configuration. The basic methodology of vehicle classification is provided, together with an example of class separation between two vehicles with similar or overlapping dimensions. Examples of classification accuracy, sensor limitations and possible improvements are given. TRRL are evaluating automatic count and classification equipment at 8 trial sites, and some initial experience with site equipment, and data accuracy are also included. (A) This paper was presented at the OECD seminar on road traffic information held at the Transport and Rood Research Laboratory, Crowthorne, 23-25 September 1980. For covering abstract of the seminar see IRRD no 267449.
Abstract