In planning motorways, four specific speeds are taken into account: 80, 100, 120 and 140 km/h; as far as horizontal bends are concerned provision is made for minimum normal radii which can, in hilly terrain, be reduced to absolute minima. For motorways, the minimum superelevation is increased compared to highways, in order to obtain greater homogeneity of speeds. The number of straight lines and large radius bends, which leads to monotony, is reduced. The length of transition curves between straight sections and circular curves is determined by the three following conditions: the dynamic condition (limitation of centripetal acceleration), twisting condition and condition of optical comfort. Representative curves are obtained for these conditions and the envelope, which give the correct clothoid length as a function of the specific speed and the circular curve radius. /TRRL/

  • Availability:
  • Corporate Authors:

    Springer Verlag

    175 5th Avenue
    New York, NY  United States  10010

    Asociacion Espanda de la Carretera

    Serrana 57-3A Planta, Apartado 1052
    Madrid,   Spain 
  • Authors:
    • Llamazares, O
  • Publication Date: 1976-11


  • Spanish

Media Info

  • Features: Figures; Photos; Tables;
  • Pagination: p. 27-28
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00302687
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Dec 29 1979 12:00AM