According to the Idaho State Police, the troopers do not lock in the
speed of a violator on the RADAR. The trooper observes the speed
of an approaching vehicle and by not locking in on the speed, they can
determine if the speed is increasing or decreasing. The trooper uses
visual observation and an audible sound emitted by the RADAR to
determine which vehicle the RADAR is identifying. Locking the
RADAR increases the chance of the wrong vehicle being identified.
As a result, the trooper cannot show you the speed readout on the RADAR
if you are stopped for speeding.
Idaho’s Office of Highway Operations and Safety endorses the use of
laser radar units for Idaho’s law enforcement patrol officers.
The laser radar units contain a computer chip that can identify how
fast the car is traveling and the distance between two cars. An
additional enhancement is that they can pick out one car in a
group.
If you look up in the sky you might also see law enforcement. A
plane or helicopter can determine how fast a vehicle is going by how
long it takes to travel on a specific stretch of highway.