Before getting their commercial driver's license, long-haul truck drivers must pass the CDL exam.The CDL exam varies from state to state, but certain questions on safety, driving an 80-foot vehicle, and sharing the road with others are the same.Here are 15 questions from a sample CDL exam. You need a score of 80% to pass.Visit Business Insider's homepage for more stories.Not just anyone can control a vehicle that can be up to 80,000 pounds.Before long-haul truckers can start working, they need a commercial driver's license. One requirement for that is passing the CDL exam.There are several classes of the license, including A, B, and C. Class A, the most common, allows the holder to drive a truck and a trailer weighing more than 26,001 pounds. You can also get a variety of endorsements to transport hazardous materials or double or triple trailers.The exam varies from state to state, but certain questions on safety and sharing the road with others are the same.Here are 15 questions from a sample CDL exam, provided from Driving-Tests.org's database of previous exams. You need a score of 80% (12/15 questions correct) to pass. SEE ALSO:Truck driver salary varies by almost $20,000 across the US ' here's where truckers make the most, ranked by stateJoin the conversation about this storyNOW WATCH: How NASCAR's banked turns help cars go faster Click here to read full news..