Washington CDL — Air Brakes practice
Signals & Pavement Markings
How to read traffic signals, lane lines, and pavement markings — including yellow and white lines, arrows, and flashing lights.
Questions reviewed against the official Washington driver handbook · July 7, 2026
3 questions · pass with 2 correct. You get instant feedback and an explanation after every answer.
Study questions with answers
3 sample Signals & Pavement Markings questions with the correct answer, a short explanation, and the official handbook reference. Read through them, then take the quiz above.
1. The visible low-air-pressure warning must come on before tank pressure drops below what level?
Correct answer: 60 psi.
A warning you can see is required to activate before pressure falls below 60 psi (or half the governor cut-out on older vehicles).
Source: Section 5.1.11 - Low Air Pressure Warning
2. What is a 'wig wag' on an air brake vehicle?
Correct answer: A mechanical arm that drops into view when pressure falls below 60 psi.
The wig wag is a low-air warning device: a mechanical arm swings into the driver's view when system pressure drops below 60 psi.
Source: Section 5.1.11 - Low Air Pressure Warning
3. How does an air brake system let drivers behind you know that you are braking?
Correct answer: Through an air-pressure-operated electric switch that turns on the brake lights.
The stop light switch is an electric switch operated by air pressure; applying the air brakes closes it and turns on the brake lights to warn following drivers.
Source: Section 5.1.12 - Stop Light Switch
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Every Washington question is written from the official Washington driver handbook and checked against its current edition. DMV Test Free is a free, independent study resource — not affiliated with any DMV or government agency. About DMV Test Free