Stopping Distance & Brake Performance Flashcards
7 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 7 Stopping Distance & Brake Performance flashcards as text
How does wet pavement affect the stopping distance of a vehicle with air brakes?
Answer: Wet pavement can double the stopping distance compared to dry pavement
Wet pavement significantly reduces tire-to-road friction, which can approximately double the stopping distance compared to dry conditions.
What happens to stopping distance when wheel brakes are out of adjustment on a multi-axle vehicle?
Answer: Stopping distance increases because fewer brakes are doing the work
When brakes are out of adjustment, those brake assemblies contribute less stopping force, meaning fewer brakes must do all the work, significantly increasing stopping distance.
Which condition is MOST likely to cause brake fade on a long downhill grade?
Answer: Continuous heavy braking that overheats the brake drums and linings
Continuous heavy braking generates heat that raises drum and lining temperatures until the friction material can no longer effectively slow the vehicle, causing brake fade.
What is the recommended technique to avoid brake fade on a long, steep downgrade?
Answer: Select a low gear before starting down and use light steady brake applications to control speed
Using a low gear to harness engine braking combined with light, steady service brake applications controls speed without overheating the brakes.
How does a properly adjusted automatic slack adjuster contribute to optimal stopping distance?
Answer: It maintains the correct pushrod stroke length so brake shoes contact the drum with full force
Proper slack adjuster adjustment ensures the brake lining contacts the drum at the correct distance, delivering maximum braking force with each application.
At 60 mph, approximately how far does a truck travel during the driver's perception and reaction time before the brakes are even applied?
Answer: About 132 feet
At 60 mph, a vehicle travels roughly 88 feet per second, and with a 1.5-second combined perception-reaction time, the truck covers approximately 132 feet before braking begins.
Which of the following road conditions causes the GREATEST reduction in tire-road friction and the longest stopping distance?
Answer: Black ice on pavement
Black ice is nearly frictionless and can increase stopping distance by ten times or more compared to dry pavement, making it the most dangerous surface condition.