To examine the effect of anti-lock brakes with summer, all-season, and winter type tires on ice and snow, tests were carried out on a flooded frozen track and on asphaltic pavement with newly fallen snow. The friction values obtained were compared with those reported by other investigators.
The most important factor governing the amount of traction on snow or ice was the temperature of the tire/snow/ice interface at the time of the test. The same tires on the same surface produced twice as much or half as much traction during tests done later after the temperature had changed. Surface roughness was also a significant factor.
Overall, decelerations ranged from 0.10 g to 0.30 g. This is consistent with the majority of earlier published data.
Directional control was often lost during tests with the anti-lock brake system inactive. Control was never lost during tests with the anti-lock brake system active. Under most circumstances the anti-lock brake system offered a slight advantage providing greater deceleration than was recorded in tests with the anti-lock system inactive. With fresh snow on pavement and a temperature just below freezing, somewhat better traction was obtained with the anti-lock brake system inactive.
On smooth surfaces of ice or hard packed snow the winter, all weather, and summer tires had very similar traction. Any possible differences in deceleration were masked by variations attributable to changes in surface temperature. Snow tires gave the best traction in loose snow.
