For people for come into contact with Illinois State Police

[richardboy316]

Enforcement
The Illinois State Police utilizes hand-held radar, moving radar, pacing, laser speed measurement devices and air speed measurement to determine the speed of vehicles.
The first mechanical means to measure vehicle speed was the stop watch. As early as 1906 the courts accepted that the time it took a vehicle to travel between two points could be converted to vehicle speed. Using the speedometer and keeping pace with another vehicle has been utilized since 1916.
The Illinois State Police started using radar in 1956. Radar uses radio waves that bounce off moving vehicles. In 1959 the state police started using the stop watch method of measuring vehicle speeds from airplanes. The state police now operate a fleet of fixed-wing aircraft for speed enforcement.
In the 1970's, hand-held radar was made available to most troopers. In the 1980's, moving radar enabled troopers to clock the speed of vehicles approaching from the front or rear while driving down the highway. In the 1990's, laser speed measuring devices were introduced. The laser devices use laser light beams that bounce off a moving vehicle.

* Approximately 32 percent of all fatal crashes are speed-related.
* Speed-related crashes most often involve only a single vehicle.
* Speed was found to be one of the most prevalent driver-error-related causes contributing to fatal crashes in 1992.
* The number of vehicles operating at higher speeds on 65 mile per hour interstate highways has increased. This has resulted in:
o increased chance of a collision due to increased speed variance.
o greater risk of fatality resulting from higher crash impact speeds.
* Of all drivers involved in speed-related fatal crashes in 1992, about 42 percent were under the influence of alcohol. Less than 29 percent of drivers in all fatal crashes were under the influence of alcohol.

[WRC]

and they introduced photo radar vans in May 2006