TRANSVERSE GRADING AND TRAFFIC SAFETY. POSSIBLE INFLUENCE OF NEGATIVE TRANSVERSE GRADING

QUERNEIGUNG UND FAHRSICHERHEIT. MOEGLICHE EINFLUESSE DER NEGATIVEN QUERNEIGUNG

Part one discusses DRAINAGE OF RAIN WATER FROM PERFECTLY LEVEL ROAD SURFACES (MEASUREMENT OF NEGATIVE TRANSVERSE GRADING). The hydrodynamic process of rain water drainage is studied with four factors: rain, grading, surface roughness, length of drainage path. Results: thickness of water film increases degressively with rain intensity; increase of grading to 2.5%-3% decreases thickness of water film significantly; road surface texture has little influence; thickness of water film increases degreesively with length of drainage path. Wind may increase thickness of water film significantly. Part two discusses MINIMUM RADIUS OF 2.5% FOR NEGATIVE TRANSVERSE GRADING. The research on rain water drainage showed that the decrease of traffic safety on wet curves with negative grading is caused by the decrease of friction due to insufficient drainage of the road surface. It follows that the minimum and maximum negative transverse grading has to be 2.5%. This part considers negative transverse grading of 2.5% from the point of view of traffic engineering. A minimum radius of 5000m for curves on highways in proposed. It is safe for speeds up to 145 km/h and equally so for both positive and negative transverse grading.

  • Availability:
  • Corporate Authors:

    MINISTRY OF TRANSPORT

    TOKYO,   Japan 
  • Authors:
    • KALENDER, U
  • Publication Date: 1974

Language

  • German

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00072180
  • Record Type: Publication
  • Source Agency: Transportation Systems Center
  • Files: TRIS
  • Created Date: Nov 5 1975 12:00AM