At one time in this country, anyone who had a driver's license could operate a commercial vehicle, no matter how big the vehicle or how specialized the driving requirements. Trucking accidents multiplied, and unsafe drivers were able to obtain multiple licenses and hide their poor driving record from one state to another. That all changed in 1986 with the Commercial Motor Vehicle Safety Act. Requirements for commercial truck driver licenses was standardized and a national database of commercial driving records was created. Now, an applicant for a truck driver license must be at least 21 years old and pass both a written test and a driving test. They must also be proficient in operating large vehicles over 26,000 pounds and carrying 16 or more passengers safely. Some states also require specific permits for specialized vehicles, such as school buses and double or triple tractor-trailers.