Abstract: An anti-skid braking system control method determines the brake torque on a wheel of a road vehicle to prevent wheel lock-up while retaining braking force. The method utilizes a wheel slip-wheel acceleration phase plane (400), which is divided into at least three and preferably four wedge-shaped sectors (401, 402, 403, 404) meeting at a central point (440), each sector representing one of three available brake control actions (A, H, R) to be taken. The vehicle's wheel slip and wheel acceleration are estimated, a representation of the phase plane is used to determine in which sector the slip/acceleration coordinate lies, and a control command is output to the system for effecting the desired control action in accordance with the sector determined. The control method is adaptive to vehicle speed.