On September 1, 1939, the Wisconsin legislature passed a statute creating the Motor Vehicle Department, which consisted of three divisions. The new "enforcement division" began with 46 "inspectors" to enforce state motor vehicle codes and regulate motor carriers. This was the nucleus of the Wisconsin State Patrol.
State Patrol radio first went on the air on February 1, 1943, operating station WIZR on a frequency of 31.5 megahertz. It was able to communicate with the patrol's mobile units, as well as with most of the municipal and county law enforcement short-wave stations.
Formal education and instruction began in 1955 with the establishment of a training academy. Today, the WI State Patrol Academy (WSPA) not only trains troopers and inspectors, but also trains federal, state, and local law enforcement officers- offering a number of training opportunities in a variety of disciplines.
In 1970, the statutory limit for the number of troopers in Wisconsin increased to 400 (WI ss. 110.07) - which number remains in effect today along with 112 motor carrier inspectors. The division currently operates 16 safety and weight enforcement facilities along with seven posts within five regions. Additional offices are located at the Division Headquarters inside the Hill Farms State Office Building in Madison and WisDOT Traffic Management Center in Milwaukee.