HILLCRESTS: PROBLEMS OF VERTICAL LINE OF SIGHT AND VISIBILITY

In the paper the stopping and passing sight distance criteria for the vertical curvature of roads at hillcrests are compared. Three particular difficulties with the criteria are considered (1) the visibility of an object coming into view being a function of the area of the object, the contrast between the object and its background, and the light level. (2) for stopping sight distances the effective driver eye height at night is the headlamp height, and (3) visibility distances in the meeting-vehicle situation at night time and at hillcrests can be considerably less than the minimum stopping sight distances. Problems of siting guard rails at hillcrests are also discussed. /TRRL/

• Corporate Authors:

  Organisation for Economic Co-operation and Development (OECD)

  2, rue André Pascal
  Paris,   France  75775 Paris Cedex 16
• Authors:
  • HILLS, B
• Publication Date: 1976

Language

• English

Media Info

• Features: Figures; Photos; References; Tables;
• Pagination: p. 29-39
• Serial:
  • Traffic Injury Research Foundation of Canada
  • Publisher: Traffic Injury Research Foundation (TIRF)

Subject/Index Terms

• TRT Terms: Braking performance; Conferences; Contrast; Curvature; Eye; Guardrails; Headlamps; Highway design; Layout; Light; Line of sight; Night; Night visibility; Passing; Passing sight distance; Slopes; Stopping sight distance; Visibility; Visibility distance
• Old TRIS Terms: Hillslopes
• ITRD Terms: 1695: Braking distance; 8525: Conference; 6794: Contrast (visual); 2855: Highway design; 2885: Layout; 9052: Night; 1822: Overtaking; 6783: Visibility; 6793: Visibility distance
• Subject Areas: Design; Highways; Planning and Forecasting; I21: Planning of Transport Infrastructure;

Filing Info

• Accession Number: 00153297
• Record Type: Publication
• Source Agency: Transport and Road Research Laboratory (TRRL)
• Report/Paper Numbers: Analytic
• Files: ITRD, TRIS
• Created Date: Sep 20 1977 12:00AM