Any jobs that prepare you to drive anything larger than a 15-passenger van for your town as a volunteer requires you to take a commercial driver safety course. If you were to try to drive the 15-passenger vehicle across town or state as a van driver, you would actually be considered a small bus driver and would likely need a CDL Safety Course. Actually, designed for drivers of Class 7 and Class 8 trucks, the CDL (Commercial Driver’s License) is required to drive in interstate commerce. In other words, if you use the Interstate system for anything, then you will be required to obtain a CDL and pass a safety course.
For more info, see Truck Driver Safety Tips