Method of adjustment during stability control of a vehicle

A method of adjusting a test braking pulse used for stability control of a vehicle during a subsequent period of rollover assessment of the vehicle, including the steps of:

• applying a first test braking pulse to at least one wheel of the vehicle, the application of the test braking pulse comprising operating a brake actuator via an ABS to apply a low level braking pressure of the wheel,
• determining a first longitudinal acceleration of the vehicle during the test braking pulse,
• obtaining a second longitudinal acceleration indicative of the longitudinal acceleration of the vehicle when the test braking pulse is not being applied, to provide a reference value,
• calculating a change in longitudinal acceleration during the test braking pulse by comparing the first longitudinal acceleration against the reference value, and
• determining;
• whether the change in longitudinal acceleration during the test braking pulse is acceptable and if not, adjusting the level of the braking pressure applied in a subsequent test braking pulse;
• wherein the step of determining the first longitudinal acceleration includes measuring the longitudinal acceleration of the vehicle over a first predetermined time period and the step of determining the second longitudinal acceleration includes measuring the longitudinal acceleration of the vehicle over a second predetermined time period, wherein the second predetermined time period over which the second longitudinal acceleration is measured is longer than the first predetermined time period over which the first longitudinal acceleration is measured such that the second longitudinal acceleration defines the reference value to assist in comparing the first longitudinal acceleration against the reference value while calculating the change in longitudinal acceleration for the rollover assessment.