What is the requirement for brakes in case of an emergency?

The requirement for brakes in the event of an emergency is that they must be able to hold at least two wheels. This is critical for ensuring that the vehicle remains stable and can come to a complete stop when necessary. Having a braking system that can effectively engage two wheels maximizes the vehicle's stopping power and reduces the risk of skidding or losing control, which is especially important in emergency situations where rapid response is essential for safety.

Braking systems typically include both the primary brakes and a secondary system, like the hand or emergency brake. The design requirement to engage at least two wheels ensures redundancy and enhances the vehicle's overall safety. If only one wheel could be stopped, it might lead to an imbalance, making the vehicle difficult to control. Therefore, the necessity for brakes to effectively engage at least two wheels is a standard safety practice in vehicle design.