Coefficient of friction (mu)
Definition
The dimensionless ratio of frictional force to normal force between tire and road. It determines how quickly a skidding vehicle decelerates. Typical dry asphalt values range from 0.65 to 0.80; wet surfaces fall to 0.40-0.60.
Related terms
- Conservation of momentum
- In a collision, the vector sum of all momenta (mass × velocity) before impact equals the vector sum after, provided no significant...
- Critical speed yaw mark
- Curved scuff marks deposited when a vehicle slides sideways. The radius of curvature and friction coefficient yield the vehicle's minimum speed at...
- Delta-V
- The change in vehicle velocity during the crash event, recorded by the EDR as a time-history. It is the integral of the...
- Perception-reaction time (PRT)
- The elapsed time from when a driver can first perceive a hazard to when the brakes begin to apply. Olson and Farber...
- Skid mark
- A dark rubber deposit left when locked wheels slide along the road surface. Length combined with the friction coefficient allows calculation of...
Explained in
- Accident Reconstruction PhysicsThe dimensionless ratio of frictional force to normal force between tire and road. It determines how quickly a skidding vehicle decelerates. Typical dry asphal...