Roadside Area Design – Swedish and Scandinavian Experience

This paper gives an overview of the development of Swedish guidelines and requirements for roadside areas in design and speed limit decisions from the first introduction of safety in the mid 70:ies to date. Major Swedish efforts to study traffic safety impacts are also summarized and commented. Important conclusions for Swedish practice are drawn. The present SRA, Swedish Road Administration, opinion based on experience claim modern guard-rails to be a better traffic safety option than smooth roadside design in most conditions. The exceptions would be deep soil cuts and low fills with very large clear zones. The major con of guard-rails is maintenance costs. A slope guard-rail has been developed with the purpose to enable guard-rail implementation in existing 1:3 fore slopes on two-lane roads. The concept is to install the barrier in the slope to avoid problems for pedestrians and bikers and also for snow removal using the traditional location at the edge of the carriageway. The advantage of 1:6 fore slopes to 1:4 and even 1:3 is very much questioned. Full scale crashes and simulation studies claim 1:3 fill slopes to be competitive with the slope end design to be important. Vshaped ditches should be avoided at the bottom. Scandinavian research based on full crash tests and simulation studies propose U-shaped cut designs with 1m 1:3 fore slope, 0.2 m ditch width and 1:1.5 or 1:2 back slopes to be superior to 1:4 and 1:6 designs. The explanation would be a bigger capacity to catch and control the vehicle within the cut. Follow-up studies indicate a major traffic safety advantage with barriers also for motorcyclists. The VTI 2+1-roads study conclude on a 40 to 50 % decrease in severe and fatal injuries for motorcyclists. Follow-up studies have been very difficult to conduct. The main reason is poor records on roadside area conditions in existing road registers and also in project documentation. The following important results could be summarized: (1) A 20 % positive difference between motorways with modern roadside areas and without. (2) A significant decrease in severity rate for single run off accidents with increasing traffic flow on two-lane roads. This is interpreted to be explained with differences in roadside areas, though not documented.

• Corporate Authors:

  Polytechnic University of Valencia

  Department of Transportation, Camino de Vera
  Valencia,   Spain  46022
• Authors:
  • Bergh, Torsten
  • Petersson, Mats
• Conference:
  • 4th International Symposium on Highway Geometric Design
  • Location: Valencia , Spain
  • Date: 2010-6-2 to 2010-6-5
• Publication Date: 2010

Language

• English

Media Info

• Media Type: CD-ROM
• Features: Figures; References;
• Pagination: 14p
• Monograph Title: 4th International Symposium on Highway Geometric Design, June 2-5, 2010, Valencia, Spain

Subject/Index Terms

• TRT Terms: Barriers (Roads); Guardrails; Highway design; Highway safety; Roadside; Slopes; Speed limits
• Geographic Terms: Scandinavia; Sweden
• Subject Areas: Design; Highways; I20: Design and Planning of Transport Infrastructure;

Filing Info

• Accession Number: 01338121
• Record Type: Publication
• Files: TRIS
• Created Date: Apr 28 2011 1:01PM