CDL General Knowledge Test Hazards, Distractions, and Fitness to Drive Summary

It is illegal to drive a commercial motor vehicle with a BAC of 0.04% or more. That is half the limit most states use for regular drivers. Any detectable amount below 0.04% still puts you out of service for 24 hours.

Wrong choices

• 0.08%: 0.08% is the general limit for regular drivers, not for CMV drivers.
• 0.10%: This is much higher than the CMV limit.

The liver removes alcohol at a fixed rate. Only time will sober a person up. Coffee, fresh air, and cold showers do not work.

Wrong choices

• Black coffee: Coffee does not remove alcohol from the body.
• A cold shower and fresh air: These do not lower blood alcohol.

Federal rules ban texting and hand-held mobile phone use while driving a CMV. The only exception is when you need to contact law enforcement or other emergency services. Pull off the road in a safe place to make other calls.

Wrong choices

• When the call is from the employer: Calls from your employer are not an exception.
• Any time traffic is light: Light traffic is not an exception.

When your body needs sleep, sleep is the only thing that works. Stop at a safe place and sleep or take a nap. A nap of half an hour does more than a half-hour coffee stop.

Wrong choices

• Drink coffee or an energy drink: Caffeine may help for a short time, but it does not cure fatigue.
• Open the window and turn up the radio: Tricks like these do not keep you safely awake.

Even below the 0.04% limit, any detectable amount of alcohol puts a CMV driver out of service for 24 hours.

Wrong choices

• Nothing, because the BAC is under the limit: Any detectable alcohol leads to an out-of-service order.
• The driver loses the CDL for life: Lifetime loss is for repeat or very serious offenses.

When confronted by an aggressive driver: make every attempt to get out of their way, avoid eye contact, and ignore gestures. Do not challenge them by speeding up. Report them to police if you can do it safely.

Wrong choices

• Hold your lane and speed up so they cannot pass: Do not challenge an aggressive driver.
• Gesture to show them they are wrong: Gestures can make the situation much worse.

Move-over laws protect people working at the roadside. Reduce speed and move to a lane that is not next to the stopped emergency vehicle or work zone if it is safe. If you cannot change lanes, slow down and pass with caution.

Wrong choices

• Stop in your lane until the emergency vehicle leaves: Stopping in a travel lane can cause a crash.
• Keep your speed and lane so traffic flows smoothly: Move-over laws require you to slow down and move over when safe.

Danger signals include eyes closing or going out of focus, trouble keeping your head up, nonstop yawning, wandering thoughts, not remembering the last few miles, drifting between lanes, and jerking the truck back into the lane. Checking your mirrors regularly is a good habit, not a warning sign.

Wrong choices

• You cannot stop yawning: Constant yawning is a warning sign of drowsiness.
• You do not remember driving the last few miles: Missing memory of the road is a warning sign of drowsiness.

For a first offense of driving a CMV with a BAC of 0.04% or more, you lose your CDL for at least one year. It is at least three years if you were driving a vehicle placarded for hazardous materials, and for life after a second offense.

Wrong choices

• Loss of the CDL for at least 3 years: 3 years applies when the vehicle is placarded for hazardous materials.
• Loss of the CDL for 60 days: The penalty is much longer than 60 days.