What should you do if you experience a brake failure while driving a commercial vehicle?

When experiencing brake failure while driving a commercial vehicle, the most effective response is to shift to a lower gear, use the emergency brake, and look for a safe location to steer the vehicle. This technique helps to slow down the vehicle's momentum through engine braking when the driver shifts to a lower gear, as lower gears can create greater resistance, aiding in deceleration. Engaging the emergency brake can also provide supplementary stopping power, although it should be done with caution to avoid locking up the wheels, which could lead to a loss of control.

Searching for a safe area to maneuver the vehicle is critical because it allows the driver to avoid obstacles or hazards that could result in a more dangerous situation. This approach prioritizes safety, not only for the driver but also for other road users.

The other options do not provide a safe or effective means of addressing brake failure. Pulling the handbrake immediately without a strategic plan may lead to skidding or loss of control, and accelerating is counterproductive; it exacerbates the situation by increasing speed while attempting to stop. Using the horn to alert others, while a responsible action in other contexts, does not directly help in managing the vehicle's safety in the event of brake failure.