Emergency Procedures & Safety Protocols Flashcards
6 cards from real Air Brake Test practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Emergency Procedures & Safety Protocols flashcards as text
What is the correct procedure when a driver experiences complete brake failure on a downhill grade?
Answer: Use a runaway truck ramp, drag the trailer if possible, or steer into terrain to slow the vehicle
A runaway truck ramp is the safest option; if unavailable, using terrain (gravel, uphill shoulder) to create drag, or controlled contact with a guardrail may be necessary to stop the vehicle.
When must a driver use the parking brake rather than relying solely on wheel chocks during an extended stop?
Answer: Whenever air pressure might drop below spring brake activation level during the stop
If air pressure can drain enough to release the spring brakes (if improperly set) during an extended stop, wheel chocks alone may not hold the vehicle; always set the spring brakes via the parking brake control.
What is the danger of driving with brakes that are 'dragging' (partially applied) on a long downhill grade?
Answer: Heat builds up and causes brake fade, potentially leading to complete loss of braking ability
Dragging brakes on a long downhill generates continuous heat; drums and linings can reach the point of thermal brake fade where they lose almost all stopping power.
How does an anti-lock braking system (ABS) assist during an emergency stop on slippery roads?
Answer: It modulates brake pressure to prevent wheel lockup, maintaining steering control while maximizing braking force
ABS rapidly cycles brake pressure on individual wheels to keep them rotating at the threshold of lockup, which preserves directional control while achieving near-maximum deceleration.
What should a driver do FIRST if the trailer supply valve (red 8-sided button) pops out while driving?
Answer: Safely pull over and stop immediately, then investigate the cause before continuing
If the trailer supply valve pops out, it indicates a major air supply problem or trailer separation; the driver must stop safely immediately to assess the situation.
Which emergency braking technique is recommended for a straight-line stop on a dry road with an older vehicle NOT equipped with ABS?
Answer: Apply firm, steady brake pressure just below the wheel lockup threshold
On a non-ABS vehicle, the optimal technique is firm, steady pressure just below wheel lockup to maximize braking force while keeping wheels rolling for steering control.