Commercial Driver FAQs in Wisconsin

Earning your commercial driver's license (CDL) is quite a bit more involved than earning your regular driver's license. That's why DMV.ORG has compiled a list of some of the most frequently asked questions regarding commercial drivers in Wisconsin.


I want to drive a truck and go over the road but I'm not 21 years old yet. Do I have to wait until I turn 21 years old to get my license?

Not at all! You may apply for your CDL if you are 18 years old and as soon as you have completed your training and are ready to take the tests required for a commercial driver license.

However, before you will be eligible to go over the road and drive outside of Wisconsin, you must be 21 years old. If you receive your CDL before then, you may drive intrastate (inside Wisconsin) until you do turn 21 years old.

I'm in truck driving school. What equipment will I be able to drive once I have my commercial driver license?

What you are allowed to drive depends on two things: the license class and which, if any, endorsements you have. Here's a breakdown:

  • Class A: Allows you to drive any combination of vehicles with a combined GVWR of 26,001 lbs. or more, if the GVWR of the vehicle or vehicles being towed is in excess of 10,000 lbs.
  • Class B: Allows you to drive a single vehicle with a GVWR of 26,001 lbs. or more or any such vehicle with a trailer with a GVWR of no more than 10,000 lbs.
  • Class C: Allows you to drive any single vehicle, or combination of vehicles, that does not meet the definition of Class A or Class B, but is either designed to transport 16 passengers or more, including the driver, or is placarded for hazardous materials.

If the equipment you want to drive is not listed in any of the above categories, then you will need to obtain an endorsement to add to your CDL. Here's a list of endorsement types, equipment, and cargo, along with the letter designation for the endorsement:

  • Bulk liquid tankers (N)
  • Doubles/Triples (T)
  • Passenger buses (P)
  • School buses (S)
  • Hazmat cargo, regardless of vehicle size (H)

If you want to be licensed to drive equipment with air brakes, then you need a separate endorsement for that. You must take an additional knowledge test and the vehicle you supply for your road test must have air brakes in order to get your authorization.


I just saw an ad for school bus drivers and I'd like to apply. I like kids, so I think I'd be good at this. Besides a basic CDL, what else do I need?

As you know, you must have a Class A CDL, plus the separate "S" endorsement in order to be allowed to drive a school bus. The Commercial Driver Manual is the section of the commercial driver manual for school bus drivers.


I've had a CDL for years and have driven over the road. I now have an opportunity to drive intrastate for one of the dairies. I can't remember if a tank with baffles requires an endorsement. Can you tell me?

Yes, regardless of the internal safety equipment, driving a tanker will require a "T" endorsement on your CDL.


I have a valid CDL from Minnesota, but my family just moved here to Wisconsin. Do I need to get a Wisconsin license, too?

Actually, you will need to surrender your Minnesota CDL and apply for a Wisconsin CDL. According to Federal law, you may hold only one driver's license of any type, at any one time. You'll have 30 days in which to surrender your Minnesota license and apply for the transfer to a Wisconsin license.


Do I need a CDL to drive a dump truck?

Yes, if the vehicle is in the class of commercial vehicle, then you must obtain a CDL before you may drive it on public roads. The same is true for other construction equipment including cement mixers and other large vehicles.


How about driving a water truck on a construction site? Does that require a CDL?

It might surprise you to learn that if you drive any heavy equipment such as a water truck, rock truck, grader, or front loader, you do not need a CDL. This is because none of this type of equipment is ever driven over public roads.

If the vehicle must be towed to the construction site, then it will not require a CDL in order to legally operate it. If it can be driven to the site over public roads, then it will require a CDL.


I got a ticket for running a red light. I know I have to tell my employer but I'd like to work another week before I do, since this will get me pulled from assignments. How much time do I have?

Unless you have already paid the fine, you can wait to tell your employer until 30 days after the conviction (meaning the court date or the date the fine is paid, if that is earlier than the court date).

You are also required to tell your employer if your license has been suspended, or revoked. And, if you develop any medical issues which would disqualify you from driving, you are required to report that to you employer, as well.

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