Abstract: An anti-skid control system for automotive hydraulic brakes screens out clearly erroneous sensor signals and/or values derived directly from sensor signals and used as anti-skid control parameters. Values for wheel speed, wheel acceleration and other brake-related factors are derived from a wheel rotation sensor signal. When the difference between successively derived wheel speed values exceeds a predetermined value, thus indicating a level of wheel acceleration which can only be an artifact due to an erroneous sensor reading, the latter wheel speed value is replaced with a back-up value. The back-up value is chosen to approximate the actual wheel speed as closely as possible, either by using the previously derived, and presumably accurate, wheel speed value or by adding to the latter a factor projecting the wheel acceleration.