Illinois State Police currently use various methods for speed limit enforcement on Illinois highways. Hand-held and moving RADAR, LIDAR, pacing, air speed utilizing the ISP fleet of aircraft, and time-distance measurement. The IL State Police uses typical marked units (Crown Victorias, Impalas, and Chargers, Ford Police Interceptor) as well as unmarked units of vehicles ranging from Crown Victorias to Grand Prix GTPs to LS-1 powered Z28s to Mustang GTs. The Mustangs, Camaros, and other vehicles are for a program created to combat aggressive driving and speeding. Lightbars used on marked units are Code 3 X2100 LED units, Federal Signal Legend units and Code 3 MX7000 halogen/strobe units. Prior to that, it was a mixture of the Code 3 MX7000s and Federal Signal JetSonics and Federal Signal Vistas.