ANTISKID CONTROL WITH SURFACE FRICTION COMPENSATION BY PROLONGED DOWN-PRESSURE OPERATION

In an antiskid control system for a motor vehicle, the speed and acceleration of at least one vehicle wheel are detected, and from the detected wheel speed, the speed of the vehicle is estimated. First and second variable threshold values are derived from the vehicle speed. The wheel speed and acceleration are compared with the first and second thresholds, respectively, to estimate the level of road surface friction and to operate solenoid-operated hydraulic brake pressure decreasing means. The operating period of the pressure decreasing means is controlled in accordance with the estimated road surface friction to prevent excessive reduction of the brake pressure and premature locking of the wheels.