The Truth about Speed Enforcement
How radar and laser guns measure your speed
•
Why they make mistakes
How they are used unfairly
•
How to protect yourself
The secret they don’t want you to know: When traffic radar shows a speed reading, it does not indicate which vehicle is being clocked.
Radar
How traffic radar works
Traffic radar units send out a wide
radar beam that’s similar to an invisible
spotlight. The radar beam widens as it
travels, and measures several hundred
feet wide at a distance of one-half mile. So
a traffic radar unit simultaneously “sees”
virtually all cars in sight. The radar beam
hits oncoming cars, and is reflected back
to the radar unit, which can calculate
speeds from those reflections.
Radar can be used from a police car
that’s either stationary or moving, since
it does not require precise aiming to
clock traffic speeds. There are also hand-
held units that can be operated from a
car, motorcycle, or an officer standing at
the side of the road.
How far away can radar clock you?
Radar range depends on the size and
shape of the vehicle. Radar can track a
large truck from over one mile away, even
too far to be seen by eye. But some sports
cars bounce back such a weak signal that
they must be within 500 feet to be clocked.
If all vehicles were identical, the
strongest reflection would be from the
closest car. But different vehicles reflect
different amounts of the radar signal.
Radar’s most common error:
mistaken identity
Because of this inherent flaw of
traffic radar, an officer could be
looking at your car while his radar
unit is actually clocking the
speed of a large truck far down
the road—perhaps even out of
sight. And since his radar doesn’t
tell him which vehicle it is reading,
the police officer might mistakenly
think that you are responsible for the
speed displayed. And give a ticket to
you instead of the truck driver.
More than a dozen technical
errors for traffic radar have also
been documented, but mistaken identity
(technically called a “target identification
error”) is by far the most common.
The bottom line
Tickets can be given anywhere, for
any reason, at any time.
How radar makes mistakes
Although traffic radar receives
reflected signals from all cars within
range, it has no way to display all the
different speeds, and no way to even
decide which car is traveling which
speed. In fact, traffic radar displays only
a single number, usually the speed of the
strongest reflected signal.
Radar speed readings caused by distant trucks
are a common source of undeserved tickets.
Since radar does not require precise aiming,
it is even used by unmanned speed trailers.
For a free printed copy of this report, call toll free 1-888-8 ESCORT
