Close-following on the motorway

Abstract

In an observational study of over 2000 close-following (tailgating) incidents in the centre lane on the Bedfordshire stretch of the Ml motorway, 20% involved a gap of less than 0·5 s. The proportion of lorry tailgaters was about equal to that of car tailgaters, although a disproportionately greater number of lorries were involved in ‘rear-end shunt’ collisions, as recorded by Bedfordshire County Council. Leading/tailgating vehicle dyads were significantly more frequently lorry/lorry and car/car than they were either lorry/car or car/lorry. When the state of other lanes, during tailgating, was examined, it was found that outside-lane-being-clear (unnecessary) but inside-lane-being-clear (provoked) tailgating by cars was greater than expected by chance, while simple unnecessary car tailgating was less. Provoked lorry tailgating, however, was less than expected, although greater when the inside lane was occupied (unprovoked), regardless of the state of the prohibited outside lane. When lane state and dyad co...