Alaska CDL Practice Test 2026

Not quiteCorrect answer: B — It takes the pulling load off the locking jaws so the release lever will move

A coupling that has been pulling all day has the kingpin pressed hard against one face of the jaws, and the lever will not travel against that load. Pushing back and then holding the rig there with the parking brakes leaves the jaws unloaded and free.

Forcing or prying the release handle when it will not move. The handle is telling you the jaws are still loaded, and the fix is to change the load, not to add leverage.

Not quiteCorrect answer: A — It keeps anyone else from starting the vehicle or moving it while you are alongside and underneath it.

You are about to put your hands and head next to the wheels of a vehicle heavy enough to kill you without noticing. The key in your pocket is the only guarantee that nobody else can put it in gear.

Treating the key step as a procedural formality in a checklist, rather than as lockout protection for the person about to work around the running gear.

Not quiteCorrect answer: A — 60 days

Failing to have space to drive fully through a crossing is one of the listed grade crossing offenses, and unlike serious traffic violations these disqualify on the very first conviction, starting at 60 days.

The belief that a crossing violation only matters if a train was actually approaching, and that a first offense of any kind never costs the CDL.

Not quiteCorrect answer: B — They have more energy to get rid of on every stop, and it leaves as heat in the friction surfaces

Stopping is a matter of turning motion into heat at the friction surfaces, so more mass moving at the same speed means more heat to shed. Heat is the limiting factor: brakes that are already hot from one demand have less capacity left for the next, which is why a loaded vehicle has to be planned further ahead than an empty one.

Reasoning that because heavy-vehicle brakes are designed for heavy loads, load does not stress them. Designed-for is not the same as unaffected-by; the brakes still absorb every bit of the extra heat, and heat is what makes them fade.

Not quiteCorrect answer: C — Because modulated braking lasts only as long as the air already in the tanks, and the spring brakes will set themselves once pressure gets low enough

The warning means air is leaving faster than it is being made. You can meter the brakes only while tank air lasts; once pressure falls into the low range the spring brakes set with no pedal control, and because they do not act on every axle a loaded vehicle travels far while a light one or a slick road can skid it out of control.

Treating spring brakes as an emergency backup that will stop the vehicle safely, rather than an uncontrolled application that happens at a moment of the leak's choosing.

Not quiteCorrect answer: A — The vehicle directly in front of it

Rear-ending the vehicle ahead is the most common commercial vehicle crash, and following too closely is the usual cause, which is why space ahead is treated as the most valuable space around the vehicle.

The belief that a heavy vehicle's main crash risk comes from cars behind it, which leads drivers to watch mirrors while neglecting the gap they control.

Not quiteCorrect answer: C — Walk the area on foot first and check what hangs above the trailer's path

Overhanging objects sit outside the mirror's field of view and are easy to lose against the sky, so the only reliable check is a look from outside the vehicle before the trailer ever moves.

The belief that mirrors show everything that matters while backing, when the hazards that take off a trailer roof are precisely the ones mirrors do not cover.

Not quiteCorrect answer: C — It sharply shortens how far ahead they can see, when high beams should be used any time no other vehicle is close enough to be blinded

The high beam exists to extend sight distance on unlit road, and on a dark highway that extra reach is most of your available warning time. A driver who never uses it has voluntarily cut the distance in which a hazard can appear and still be avoided.

Treating low beams as the default courteous setting. Permanently dimmed lights feel considerate, but on empty road the courtesy buys nobody anything and costs the driver the warning distance.

Not quiteCorrect answer: C — Brake early and gently, instead of making a panic stop that can lock the wheels and swing the trailer

Space is what turns an emergency into a routine slowdown. A gradual application keeps the wheels turning and the trailer behind you, while the hard stab that space would have prevented is what starts most jackknifes.

Treating following distance as a paperwork rule rather than the thing that decides whether your next stop is gradual or violent.

Not quiteCorrect answer: A — Keep the vehicle out of service until the defect is repaired or certified as not needing repair.

An uncertified safety defect means nobody has confirmed the vehicle is fit to drive. Once you know that, the decision to move it is yours, and so is the outcome when the hose wears through on a downgrade.

Believing that re-reporting a known defect discharges the driver's duty, when writing it down a second time changes nothing about the condition of the hose.

Not quiteCorrect answer: C — Stay in the right lane and let the faster traffic go around you

Heavy vehicles get tailgated mainly when they cannot keep pace, and keeping right leaves the passing lane open so the queue behind you can clear instead of crowding your bumper.

The belief that a slow-moving heavy vehicle is entitled to any lane it can hold, when occupying a passing lane at reduced speed is what creates the tailgating pressure in the first place.

Not quiteCorrect answer: C — Warn the traffic behind you as you slow, with your four-way flashers or a touch on the brake pedal

The traffic behind you is the immediate threat when a heavy vehicle slows in a compressed lane, and drivers near work zones are already distracted. A flasher or brake-light signal gives them the notice your deceleration alone will not.

Thinking the traffic behind is somebody else's problem, or that clearing the zone quickly is the safer trade. Speed inside a work zone raises both the risk to workers and the odds of the rear-end collision you were trying to escape.

Not quiteCorrect answer: B — Three years

The base penalty for a first offense is one year, but hauling placarded material raises what a crash would cost, so the law lengthens the disqualification to three years for the same conduct in that vehicle.

Assuming a first offense always carries the same one-year penalty, without noticing that the cargo being hauled changes the length.

Not quiteCorrect answer: B — The loss is too great; a combination may not lose more than 4 psi in that minute

Holding the pedal down pressurizes the service side as well, so the limit rises slightly, to 3 psi for a single vehicle and 4 psi for a combination. A 5 psi drop exceeds that, meaning a leak that must be found and repaired before the vehicle moves, or air can run out on the road.

Rationalizing a slightly excessive drop as normal for an older combination, when the whole point of the timed test is that the threshold is fixed.

Not quiteCorrect answer: B — When it is necessary in order to reach law enforcement or other emergency services

The rules carve out one narrow exception, for contacting law enforcement or emergency services when necessary. Everything else, including business urgency, falls outside it.

Believing that stopped in traffic means not driving, or that an employer's demand creates a legal defence. Neither one appears in the exception, and both are the excuses that produce repeat convictions.

Not quiteCorrect answer: C — The driver is placed out of service for 24 hours

Below the prosecution threshold the law still refuses to let the driver continue, so it removes him from the road for a full day. It is a separate consequence from the one-year disqualification, not a lesser version of it.

The belief that any reading under 0.04 percent carries no consequence at all, so a small amount of alcohol is treated as safe to drive on.

Not quiteCorrect answer: C — A driver behind may read it as a left turn and pass on the right, into the trailer's path

The initial drift left is an unintended signal, and the driver who accepts that invitation places his car in the space the trailer must occupy a moment later.

The belief that other drivers interpret a heavy vehicle's positioning the way the truck driver intends, rather than the way it looks from a car behind.

Not quiteCorrect answer: C — Get the speed off before the bend begins, and hold a gear low enough to pull slightly all the way round

The tires can only deliver so much grip, and in a curve most of it is already committed to turning. Braking asks for more than is left, which is why wheels lock and skid so easily mid-curve. Arriving already slowed, in a gear that allows light acceleration, keeps the vehicle settled and under your control the whole way through.

Believing the curve itself is a fine place to scrub off speed, or that coasting in neutral is the gentlest option. Braking in a curve stacks demands on tires that are already near their limit, and neutral gives up the light drive torque that keeps the vehicle stable.

Not quiteCorrect answer: C — It starts pumping at about 100 psi and stops at about 125 psi

The governor cuts the compressor in near 100 psi as pressure falls and cuts it out near 125 psi once the tanks are charged, holding a working band well above the level where warnings and spring brakes trigger. Manufacturer specifications govern the exact figures.

Confusing governor settings with the low pressure warning threshold, which is a danger signal, not a normal operating point.

Not quiteCorrect answer: C — 120 days

The scale steps up rather than repeating: two violations in three years brings 60 days, and reaching three or more in that window doubles it to 120 days.

Assuming every additional serious violation simply repeats the previous penalty instead of escalating it.