The Automatic Core Census of Road Traffic in Great Britain

This paper describes how, in order to develop a national policy on road construction, improvement or repair, many factors have to be taken into consideration. Foremost, among these is the need to know existing levels of traffic, both nationally and along specific roads. Upon an understanding of historical patterns of traffic estimates can be built for future traffic requirements and the Department of Transport has introduced two censuses to enable this to be done, the core census and the rotating, or link based census. The rotating census of traffic involves manual counts on every motorway, trunk and principal road section between major junctions as well as about 4,500 sites on minor roads. In any one year counting takes place at a sixth of these sites for one 12 hour day. The core census of traffic is more intensive but limited to a smaller number of sites and is designed to give estimates of national traffic trends by type of vehicle and road.