Question While driving, ____ generally holds spring brakes in place. Answers Air pressure Electricity Gasoline Explanation While driving, spring brakes are generally held in place by air pressure. If the air pressure gets low enough, the springs will activate the brakes. Take a FREE Practice Test Now This questions appears in the following tests: Alaska Knowledge Test Class A , Arizona Knowledge Test Class A , Michigan Knowledge Test Class A , Rhode Island Knowledge Test Class B , Iowa Air Brakes , Maine Air Brakes , Ohio Air Brakes ,