MIRA reports on wet braking and tread depth

London -- A study carried out for the British Rubber Manufacturers' Association has shown that statistically-significant increases in stopping distance appear at tread depths below approximately 3.5mm and, similarly, the cornering performance, as measured by the maximum achievable lateral acceleration, deteriorates more rapidly.

The test procedure is largely based upon ISO TC31/SC3 WG18 Draft N27-4.0 Straight Line Braking”. For each measured brake stop the test vehicle was accelerated to approximately 85km/h whereupon the driver applied maximum brake pedal pressure to invoke a full ABS controlled deceleration to standstill.