You or your drivers, according to federal law, need a commercial drivers license (CDL) to operate a vehicle or a combination of vehicles with an overall gross vehicle weight rating (GVWR) of 26,001 lbs. or more. According to the U.S. Department of Transportation, an operator must have a Class A, Class B or Class C CDL, depending on the vehicle and trailer weight.

The laws dont only apply to big trucks and trailers. Tim Cahall of The Main Event in Mount Airy, Md., says it is possible to have a CDL restriction even when using a pickup truck. "If you have a big pickup and a 10,001-lb. trailer, you have to have a CDL-A," he says. Cahall says his drivers, however, are not CDL-certified because they dont pull trailers more than 10,000 lbs. in weight.

Just what class of license required is determined as follows:

Class A Any combination of vehicles and trailers with a GVWR of 26,001 lbs. or more requires a Class A CDL, provided that any towed vehicles or trailers have a GVWR of more than 10,000 lbs.

Class B Any single vehicle with a GVWR of 26,001 lbs. or more, or any such vehicle towing another vehicle or trailer with a GVWR of less than 10,000 lbs. requires a Class B CDL.

Class C Any single vehicle or combination of vehicles that does not fall under either Class A or Class B, but is designed to transport 16 or more passengers, including the driver, or is placarded for hazardous materials, requires a Class C CDL for operation.

Additional endorsements may be necessary for certain vehicles or vehicle combinations, including tank trucks and double or triple trailers. While federal laws provide the minimum requirements for commercial motor vehicle (CMV) operation, individual states are in charge of developing their own licensing requirements, which must be at least as stringent as the federal laws. States also may impose additional restrictions and rental stores should check with the state department of transportation for additions to federal regulations.

The laws also are known to change, so it is important to keep yourself informed. "Its amazing at how these laws get changed and how they dont really educate us on them," says Jerry Kortesmaki, owner, London Road Rental Center, Duluth, Minn. "Very few people know. Im trying to educate my customers when they come in."

For more information on the federal laws, visit the Federal Motor Carrier Safety Administration (FMCSA) Web site at www.fmcsa.dot.gov/registration-licensing/cdl/cdl.htm.