Travel speeds and overtaking were measured by means of the registration-plate method on Finnish and Swedish two-lane, limited-access road, of 28 and 16 km in length. A linear relationship was found between the with-flow traffic volume and mean travel speed until volumes of about 1500 vehicles per hour, at least. There was a clear difference, however, between the Finnish and Swedish road: for an increase of 1000 veh/h in with-flow volume, the mean travel speed decreased 11.8 km/h in Finland but only 3.9 km/h in Sweden. A clear difference in overtaking frequency was also found between the two countries. The number of overtakings per vehicle and kilometer in Sweden was about twice as high as in Finland at all traffic volumes. For instance, at a with-flow traffic volume of 1 000 veh/km the average frequency of overtakings performed by passenger cars in Sweden was even 40 per 100 km driving. The video recordings from both roads showed that this difference was due to the fact that Swedish car drivers normally steer to the shoulder when a faster car is approaching from behind, thus allowing a free opportunity to overtake without any delay. In Finland, instead, this strategy is only applied by lorry and van drivers whereas slower cars use wide shoulders to facilitate overtaking only occasionally. Thus the Swedish drivers use wide two-lane roads as if they were four-lane ones exept for the fact that the additional lane, i.e. shoulder, is not used continuously but only to help overtaking without any delay. (TRRL)

  • Availability:
  • Corporate Authors:

    Helsinki University, Finland

    Traffic Research Unit, Ritarikatu 5
    Helsinki,   Finland 
  • Authors:
    • SUMMALA, H
  • Publication Date: 1987


  • Finnish

Media Info

  • Features: References;
  • Pagination: 31 p.
  • Serial:
    • Reports
    • Issue Number: 13
    • Publisher: Helsinki University, Finland
    • ISSN: 0781-9935

Subject/Index Terms

Filing Info

  • Accession Number: 00492415
  • Record Type: Publication
  • Source Agency: VTT Technical Research Centre of Finland
  • ISBN: 951-45-4498-6
  • Files: ITRD, TRIS
  • Created Date: Mar 31 1990 12:00AM