Which of these, if allowed to get low, could cause you to crash?

Explanation: You should carry out frequent checks on all fluid levels but particularly brake fluid. As the brake pads or shoes wear down, the brake fluid level will drop. If it drops below the minimum mark on the fluid reservoir, air could enter the hydraulic system and lead to a loss of braking efficiency or even complete brake failure.

Category: Safety and your vehicle

References: Highway Code: Page 130