Vehicle Equipment & Safe Operation — Missouri
Missouri CDL practice test: 413 free practice questions (Based on the official driver handbook). The official format is not yet verified; check the official site before your test. Vehicle Equipment & Safe Operation: 159 questions.
Brakes, tires, lights, mirrors, seat belts, child seats and basic vehicle control.
This topic page is still being reviewed against the official handbook. Until review is finished it is hidden from search engines.
| Topic / Metric | Value |
|---|---|
| Topic | Vehicle Equipment & Safe Operation |
| License test | Missouri CDL permit (CLP) knowledge tests |
| Topic questions | 159 (38% of 413 total) |
| Review status | This topic page is still being reviewed against the official handbook. Until review is finished it is hidden from search engines. |
Official handbook
Not yet verified
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Questions (159)
1. The overhead rearview mirror is located:
- On the right side of a bus.
- On the steering wheel of a bus.
- Above the windshield inside a bus. ✓
Answer: C. Above the windshield inside a bus.
The overhead rearview mirror is mounted above the windshield inside the bus, on the driver's side. The handbook describes this mirror as mounted directly above the windshield in the driver's side area of the bus. Its job is to let you watch what passengers are doing inside the bus, and it may give a little view directly behind the bus only if the bus has a glass-bottomed rear emergency door. The handbook also points out blind spots behind the driver's seat and behind the rear bumper, and says you rely on the exterior side mirrors to watch traffic in those areas.
2. If you plan to slow down, you can warn drivers behind you by:
- Slamming on the brakes.
- Tapping the brakes a few times and before braking. ✓
- Turning on one set of turn signals.
Answer: B. Tapping the brakes a few times and before braking.
You can warn drivers behind you by tapping the brakes a few times before you actually brake, which flashes your brake lights. The handbook's Slowing Down section says to warn drivers behind you when you see you will need to slow down. A few light taps on the brake pedal, just enough to flash the brake lights, are what should warn following drivers. The handbook repeats this idea for hazards ahead, tight turns, and stopping on the road: flash your brake lights and do not stop suddenly. Tapping first gives the people behind you a heads-up before your speed actually drops.
3. When driving while pulling trailers, you should:
- Make sudden turns with the steering wheel.
- Avoid making sudden moves. ✓
- Push the accelerator to the floor when starting from a stop.
Answer: B. Avoid making sudden moves.
When you are pulling trailers, avoid making sudden moves — steer gently and smoothly so the trailer stays under control. The combination-vehicle section explains rearward amplification, the crack-the-whip effect, where the last trailer swings far more than the tractor. Because of that, a quick jerk of the steering wheel can put a trailer on its side. The handbook's advice is to steer gently and smoothly, look far down the road so you are not surprised, and slow to a safe speed before a turn. Everything in that section points to smooth, gradual control rather than abrupt steering or speed changes.
4. Cargo inside a trailer:
- Does not need to be secured.
- Should be stacked no more than three feet high.
- Should be secured to prevent movement. ✓
Answer: C. Should be secured to prevent movement.
Cargo inside a trailer should be secured so it cannot move. The handbook treats securing cargo as a handling issue, not just a flatbed issue. It says that in closed vans tie-downs can be important because shifting cargo may affect how the vehicle handles. It also describes blocking and bracing as ways to keep cargo from sliding, with blocking attached to the cargo deck and bracing running to the floor or walls. So cargo carried inside a trailer needs to be restrained against movement.
5. Anti-Lock Braking Systems (ABS):
- Reduce a vehicle's normal braking capacity.
- Are in addition to other braking systems and do not reduce a vehicle's braking power. ✓
- Are not effective on larger vehicles.
Answer: B. Are in addition to other braking systems and do not reduce a vehicle's braking power.
ABS is in addition to other braking systems and does not reduce a vehicle's braking power. The handbook describes ABS as an add-on to the brakes already on the vehicle. It says ABS neither lowers nor raises your regular braking ability. It also says ABS activates only when wheels are about to lock up. That matches the answer that ABS adds to other braking systems without cutting braking power. The handbook does not say ABS reduces normal braking capacity.
6. Mirrors should be:
- Checked only when changing lanes.
- Checked frequently. ✓
- Checked only if there is a reason to suspect a problem.
Answer: B. Checked frequently.
Mirrors should be checked frequently. The handbook's backing instructions tell you to use the mirrors on both sides and check them frequently. It treats mirror checks as a repeated habit, not something you do only for a lane change or only after something seems wrong. Because the same wording appears in the combination-vehicle and driving-safely sections, the bank's answer matches the handbook.
7. When slowing down, you should ____ to warn other drivers
- Use a turn signal
- Sound your horn
- Tap your brakes ✓
Answer: C. Tap your brakes
Tap your brakes lightly so your brake lights flash and warn the drivers behind you. The handbook's slowing-down section tells you to warn drivers behind you when you see you will need to slow. It says a few light taps on the brake pedal, enough to flash the brake lights, should warn following drivers. It adds that four-way flashers are for when you are driving very slowly or are stopped, and it advises braking early and gradually for tight turns. That makes tapping the brakes the communication method for ordinary slowing, before you get into the very-slow or stopped situations.
8. What kind of force do emergency brakes use?
- Air pressure
- Mechanical ✓
- Heavy
Answer: B. Mechanical
Emergency brakes use mechanical force. The handbook says trucks, tractors and buses must have emergency and parking brakes that are held on by mechanical force, because air pressure can leak away. Spring brakes meet this need: while driving, air pressure holds back strong springs, and when air pressure is lost, the springs apply the brakes. That is why the correct choice is mechanical force rather than air pressure.
9. What does the air compressor governor do?
- It stops the compressor from pumping air. ✓
- It turns on the air compressor.
- It stores the compressed air.
Answer: A. It stops the compressor from pumping air.
The air compressor governor controls the compressor so that it stops pumping air once tank pressure reaches the cut-out level. The handbook says the governor decides when the compressor pumps air into the storage tanks. When tank pressure climbs to the cut-out level (around 125 psi), the governor stops the compressor from pumping. When pressure drops to the cut-in level (around 100 psi), the governor lets the compressor start pumping again. So its job is to keep tank pressure inside that range, and the stopping action is what the handbook highlights at the top of the range. A governor that does not work properly may not keep enough air pressure for safe driving.
10. A wig wag is:
- A low pressure warning device. ✓
- A tube that carries air to the brakes.
- A type of air brake system.
Answer: A. A low pressure warning device.
A wig wag is a low air pressure warning device. The handbook lists the wig wag among the low air pressure warning signals required on air brake vehicles. It describes the wig wag as a mechanical arm that drops into the driver's view when tank pressure falls below 55 psi, and an automatic type rises out of view when pressure goes back above that level. That makes it a visible warning device, not part of the air supply plumbing or a separate brake system.
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Last checked: 2026-10-17 · Verified from official source
Updated: · Based on the official driver handbook