Signals & Pavement Markings

Study questions with answers

5 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. 1. On a modern air brake vehicle, the low air pressure warning must come on before tank pressure drops below what level?

   Correct answer: 60 psi

   A visible low-pressure warning is required and must alert you before pressure falls under 60 psi.

   Source: Wisconsin Commercial Driver's Manual (BDS356), Section 5.1.11 - Low air pressure warning

2. 2. What is a 'wig wag' low-pressure warning device?

   Correct answer: A mechanical arm that drops into your view when pressure falls below 60 psi

   A wig wag is a mechanical arm that swings down into the driver's line of sight when pressure sinks below 60 psi.

   Source: Wisconsin Commercial Driver's Manual (BDS356), Section 5.1.11 - Low air pressure warning

3. 3. What color is the ABS malfunction lamp on a tractor, truck, or bus?

   Correct answer: Yellow

   ABS trouble is shown by a yellow malfunction lamp, located on the instrument panel of trucks, tractors, and buses.

   Source: Wisconsin Commercial Driver's Manual (BDS356), Section 5.1.16 - Antilock braking systems (ABS)

4. 4. On a vehicle equipped with one, needing more and more application pressure to hold a steady speed points to what?

   Correct answer: The brakes are fading, so slow down and select a lower gear

   Rising application pressure to keep the same speed signals fading brakes; the right response is to slow down and drop to a lower gear.

   Source: Wisconsin Commercial Driver's Manual (BDS356), Section 5.1.10 - Application pressure gauge

5. 5. What does a supply pressure gauge tell the driver?

   Correct answer: How much air pressure is being held in the tanks

   The supply gauge reads how much air is stored in the tanks, unlike the application gauge, which reads what you are sending to the brakes.

   Source: Wisconsin Commercial Driver's Manual (BDS356), Section 5.1.9 - Supply pressure gauges