If you experience brake failure, what should you do first?

Pumping the brakes is the appropriate initial action if you experience brake failure. This technique can help build up pressure in the brake system, which may allow you to regain some braking ability, especially if the failure is due to a temporary loss of hydraulic pressure. It's a common practice that many drivers are trained to use in emergency situations, as it can potentially slow the vehicle down enough to prevent a collision and give the driver more control.

In contrast, steering to the side of the road may be a necessary action after addressing the immediate issue of brake failure, but it should not be the first step. Using the emergency horn could alert other drivers of your distress, but it does not help with stopping the vehicle. Accelerating in a situation of brake failure would worsen the problem, increasing the danger to yourself and others on the road. Therefore, the best immediate response to brake failure is to attempt to pump the brakes to regain control and reduce speed.