That depends upon the size of the truck or specifically how much weight the truck can carry. If you have a Class A Commerciall Driving License you can operate any vehicle, although you need more qualifications to handle dangerous materials. A Class B and Class C CDL will allow you to drive some medium sized vehicles up to certain weights per axle and/or passenger capacities. What type of license you need to drive a commercial truck is highly dependent on what type of material you will be moving. For starters, you will need a CDL (commercial drivers license). From there, you will need to determine what kind of additional certification you might need to transport hazardous materials, move bulk materials in a tank, or haul double or triple trailers (i.e., gravel trains).