Close following behaviour by drivers on rural two lane motorways has been studied and the results have contributed to an international drivers' behaviour research association (IDBRA) project. Video equipment was used to monitor 7325 vehicles on two rural sites, one on the M4 and another on the M5. Measurements were made over two separate periods of the day to coincide with maximum and minimum traffic flow conditions at each site. The report considers the relationship of close following to the flow, lane, speed and vehicle type and platoon size distribution is also considered. Thirty one per cent of drivers were following the vehicle ahead with a gap of less than two seconds and one half of these were within one second. A greater proportion of heavy goods vehicles than lighter vehicles close follow particularly in the overtaking lane, and also in this lane the percentage of heavy goods vehicles leading platoons is almost double that of lighter vehicles. (Author/publisher)
Abstract