​​​​​​​Friction Depends on Following Factors

Friction Depends on Following Factors

  • Type of pavement (bitumine,earthen material or WBM)

  • Roughness of the pavement (textures)

  • Condition of the pavement (dry or wet , rough or smooth)

  • Condition of the tyre (new with good thread or old worn out thread)

  • Speed of vehicle

  • Extent of break application (full or partial)

  • Load & type of pressure

  • Temperature and tyre & pavement


Old tyre friction on dry surface > New tyre on dry surface

Old tyre friction on wet surface < New tyre on wet surface

Hence new tyres are more dependable in adverse conditions then the old ones.

  • For calculation if stopping distance the longitudinal friction coefficient has to be taken as (0.35-0.40) at f=0.4 saturation available is approx 4 m/sec2
  • And transverse friction is to be taken as 0.15