After unloading a truck, may the driver assume it can now follow closer because it must stop sooner?
Correct answer: No. Reduced tire traction can make an empty truck take longer to stop.
Do not assume less load guarantees a shorter stop. The handbook warns that reduced traction can make an empty truck's stopping performance worse. Leave a gap suitable for the actual vehicle and conditions.
Source: Missouri Commercial Driver License Manual, revised August 2025, Section 2 (July 2017); 2.6.1 The Effect of Vehicle Weight on Stopping Distance; physical PDF page 30 (printed 2-14); reviewed September 15, 2026. ↗
Rain has made the pavement slippery but traffic is still moving quickly. What should a truck driver change?
Correct answer: Reduce speed and allow more stopping space for the available traction.
Wet pavement reduces traction and can lengthen stopping distance. Lower speed and additional space give more room to react and stop; a posted maximum is not a guarantee for the weather.
Source: Missouri Commercial Driver License Manual, revised August 2025, Section 2 (July 2017); 2.6.2 Slippery Surfaces; physical PDF page 30 (printed 2-14); reviewed September 15, 2026. ↗
It is below freezing and a shaded stretch of road looks wet rather than snowy. What should the driver consider?
Correct answer: The apparent wetness may be a thin layer of clear ice.
Clear ice can show the pavement beneath it and look like water. Below-freezing temperatures and shaded areas are reasons for extra caution, not reasons to rule out ice.
Source: Missouri Commercial Driver License Manual, revised August 2025, Section 2 (July 2017); 2.6.2 Identifying Slippery Surfaces; physical PDF page 30 (printed 2-14); reviewed September 15, 2026. ↗
A manually shifted truck begins hydroplaning through standing water. Which response follows the handbook's guidance?
Correct answer: Release the accelerator and disengage the clutch; avoid braking while hydroplaning.
Water can separate the tires from the road. The handbook advises easing off power and, in a manual vehicle, pushing in the clutch so the wheels turn freely, rather than braking while hydroplaning. Avoid abrupt inputs and reduce speed before standing water.
Source: Missouri Commercial Driver License Manual, revised August 2025, Section 2 (July 2017); 2.6.2 Hydroplaning; physical PDF page 31 (printed 2-15); reviewed September 15, 2026. ↗
A loaded truck has a high center of gravity. Does the speed posted for a curve guarantee that it will not roll over at that speed?
Correct answer: No. Its safe cornering speed may need to be lower.
A truck can roll over even while its tires retain grip. Load and center of gravity affect stability, so slow sufficiently before the curve rather than assuming the sign guarantees safety for the vehicle.
Source: Missouri Commercial Driver License Manual, revised August 2025, Section 2 (July 2017); 2.6.3 Speed and Curves; physical PDF page 31 (printed 2-15); reviewed September 15, 2026. ↗
At night, oncoming traffic requires low beams. What should a truck driver do if the visible road becomes shorter than the truck's stopping distance?
Correct answer: Slow enough to stop within the road distance that can be seen.
Speed must fit the available view as well as the road surface. If the truck cannot stop within the illuminated road ahead, reduce speed; another driver's lights are not a reliable substitute.
Source: Missouri Commercial Driver License Manual, revised August 2025, Section 2 (July 2017); 2.6.4 Speed and Distance Ahead; physical PDF page 31 (printed 2-15); reviewed September 15, 2026. ↗
Using the handbook's basic following-gap guideline in good conditions, what gap should a 40-foot truck leave at 35 mph?
Correct answer: At least 4 seconds.
The guideline is one second per 10 feet of vehicle length below 40 mph: 40 divided by 10 gives four seconds. This is a starting guideline, not a guarantee for poor weather or other hazards.
Source: Missouri Commercial Driver License Manual, revised August 2025, Section 2 (July 2017); 2.7.1 Space Ahead; physical PDF page 32 (printed 2-16); reviewed September 15, 2026. ↗
Using the handbook's basic guideline in good conditions, what following gap should a 60-foot rig leave at 50 mph?
Correct answer: At least 7 seconds.
Allow six seconds for 60 feet of length and add one second above 40 mph, for at least seven seconds. Increase the space further when traction, visibility or other conditions demand it.
Source: Missouri Commercial Driver License Manual, revised August 2025, Section 2 (July 2017); 2.7.1 Space Ahead; physical PDF page 32 (printed 2-16); reviewed September 15, 2026. ↗
How can a driver measure the following gap without estimating a distance in feet?
Correct answer: Count the time from the lead vehicle passing a fixed landmark until the truck reaches it.
Choose a fixed point ahead and time the interval between the lead vehicle and your vehicle reaching that same point. Compare it with a suitable following-time guideline and drop back if needed.
Source: Missouri Commercial Driver License Manual, revised August 2025, Section 2 (July 2017); 2.7.1 Space Ahead; physical PDF page 32 (printed 2-16); reviewed September 15, 2026. ↗
A car is following a truck too closely. Which adjustment helps reduce the need for a sudden stop?
Correct answer: Open more space ahead and make speed changes gradually.
More space ahead lets you slow and react gradually. Signal planned changes early and avoid retaliatory braking or acceleration, which increases risk without controlling the tailgater.
Source: Missouri Commercial Driver License Manual, revised August 2025, Section 2 (July 2017); 2.7.2 Dealing with Tailgaters Safely; physical PDF page 33 (printed 2-17); reviewed September 15, 2026. ↗
An empty, high-sided truck emerges from a sheltered tunnel into strong crosswinds. What deserves extra attention?
Correct answer: Lateral movement and clearance from vehicles alongside.
Strong winds can push a vehicle sideways, especially a light one, and exposure can change suddenly outside a tunnel. Maintain control and side space instead of traveling unnecessarily alongside other vehicles.
Source: Missouri Commercial Driver License Manual, revised August 2025, Section 2 (July 2017); 2.7.3 Strong Winds; physical PDF page 33 (printed 2-17); reviewed September 15, 2026. ↗
A cargo van cleared a low structure while loaded. After unloading, is that previous clearance enough proof that it will fit again?
Correct answer: No. The unloaded vehicle may ride higher, so clearance must be checked.
Suspension position can change vehicle height with loading. Do not assume a previous passage proves clearance now; know the current height, assess conditions and choose another route when clearance is uncertain.
Source: Missouri Commercial Driver License Manual, revised August 2025, Section 2 (July 2017); 2.7.4 Space Overhead; physical PDF page 33 (printed 2-17); reviewed September 15, 2026. ↗
A low-clearance trailer approaches a sharply raised rail crossing. What should the driver establish before attempting to cross?
Correct answer: That the vehicle can clear the crest without getting hung up.
A long, low trailer can become stranded on a raised crossing even when its front wheels pass. Ground clearance and the road profile must be suitable; do not gamble on momentum to get over the crest.
Source: Missouri Commercial Driver License Manual, revised August 2025, Section 2 (July 2017); 2.7.5 Space Below; physical PDF page 33 (printed 2-17); reviewed September 15, 2026. ↗
Why should a large-truck driver avoid swinging left at the start of a planned right turn?
Correct answer: A following driver may mistake it for a left turn and enter the space on the right.
An early swing left opens a tempting gap on the right and can mislead following traffic. Plan the turn slowly, monitor clearance and traffic, and do not treat the needed turning space as automatic right-of-way.
Source: Missouri Commercial Driver License Manual, revised August 2025, Section 2 (July 2017); 2.7.6 Right Turns; physical PDF page 34 (printed 2-18); reviewed September 15, 2026. ↗
A driver turns a long truck left too early at an intersection. What can the rear portion do?
Correct answer: Cut inside the front path and strike a vehicle or object on the left.
The rear wheels of a long vehicle follow an inside path in a turn. Starting the left turn too early can bring the vehicle's left side into nearby traffic or objects; allow space for the whole vehicle.
Source: Missouri Commercial Driver License Manual, revised August 2025, Section 2 (July 2017); 2.7.6 Left Turns; physical PDF page 34 (printed 2-18); reviewed September 15, 2026. ↗
A gap was adequate when the driver crossed a road in a car. Is it automatically adequate for a heavily loaded truck making the same crossing?
Correct answer: No. Slower acceleration and greater length can require a much larger gap.
A loaded truck may accelerate more slowly and needs more time for its entire length to clear the road. Before entering, make sure the whole vehicle can complete the crossing before conflicting traffic reaches it.
Source: Missouri Commercial Driver License Manual, revised August 2025, Section 2 (July 2017); 2.7.7 Space Needed to Cross or Enter Traffic; physical PDF page 34 (printed 2-18); reviewed September 15, 2026. ↗
