A traffic study was carried out in order to evaluate the effect of vehicle length on the accident risk when long vehicle combinations were overtaken. Also the influence of a vehicle-mounted sign indicating the length of the vehicle was investigated. The experiment was performed as a full scale test in a real traffic environment. Two test vehicles, 18 and 24 metres long respectively, were driven simultaneously along the test sections at a constant speed of 70 km/h and 10 km apart. Overtaking processes were recorded by means of film cameras on the roof of the test vehicles. The test vehicles covered a total mileage of 13640 km during the test period of eight weeks. The time gap was used as a measure of accident risk, i.e. The number of seconds elapsing between the conclusion of an overtaking operation and the time when the overtaking vehicle meets or could have met an oncoming vehicle. The differences in mean values of time gaps between the two vehicle lengths were very small. There was a slight tendency for the 24 metre vehicle to induce a greater number of hazardous overtakings than the 18 metre vehicle, but this difference has not been statistically proved. The vehicle-mounted signs indicating vehicle lengths were found to improve meeting margins. The report includes an English summary of 12 pages. /TRRL/


  • Swedish

Media Info

  • Features: Figures; Photos; Tables;
  • Pagination: 180 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00163351
  • Record Type: Publication
  • Source Agency: Swedish National Road and Transport Research Institute (VTI)
  • Report/Paper Numbers: Report No. 103 Monograph
  • Files: ITRD, TRIS
  • Created Date: Jan 13 1978 12:00AM