Police Use of Radar Guns in Utah
Police officers in Utah commonly use radar guns to determine the speed
of a vehicle. In addition to getting a ticket (citation), a driver
pulled over for speeding may also be subject to questioning or search
relating to other suspected crimes, and may end up facing charges much
more serious than a simple speeding ticket.
Before a police officer can extend the scope (subject matter) or
duration (length of time) of a basic traffic stop, the officer must
first observe some evidence of another crime. Criminal charges
including
DUI
and
drug offenses commonly
come from evidence obtained during a traffic stop. But if the officer
detains or searches a vehicle without the required constitutional
evidentiary basis, then evidence obtained as a result of a
constitutional violation may be subject to suppression under the
Fourth
Amendment.
If you are being prosecuted for a crime based on evidence obtained
during a traffic stop, it is important to have the assistance of an
experienced criminal
defense
attorney.
Contact
us today to see how we can help you.
How does a radar gun work?
Speed measurement using radar guns is based on the Doppler effect and
measures the change in frequency of radio waves.
Stationary radar guns measure the difference in frequency between the
original radio waves emitted by the unit as compared with the waves
that reflect back from the object they are trying to measure. If the
object is moving, either away from or toward the radar source, the
reflected waves will return to the unit at a different frequency
(higher or lower depending on whether the object is moving toward or
away from the radio wave source).
Imagine yourself standing on the side of a road and listening to
traffic as it passes by you. As the cars pass, you will notice the
pitch of the engine sound starting out relatively high, and then drop
down to a lower pitch as the car passes and begins to move away from
you. The faster the car is going, the greater the pitch change will be.
(The same principle is used by astronomers looking for redshift and
blueshift in light from stars to measure whether a star is moving
toward or away from the earth, and measuring how fast.)
For a radar gun mounted in a moving vehicle, the gun has to be able to
measure the frequency of two sets of radio waves: 1) the waves
reflecting back from the target vehicle; and 2) the waves reflecting
from some stationary object, such as the road surface. The difference
between those two frequencies is then used to calculate speed.
Because radio waves spread out as they travel away from the radar gun
(similar to how radio waves coming from the single point of a radio
station's transmitter will spread out to fill an entire valley), it can
be difficult to accurately target a specific vehicle in heavy traffic.
Accurate targeting becomes more difficult as the distance between the
vehicle and the radar gun increases.
Finding a Utah Criminal Defense Attorney

If
you are facing criminal prosecution in Utah, the assistance of an
experienced attorney can be vital to obtaining a good outcome. A basic
traffic stop can turn into an investigation for a much more serious
crime that can have serious long-term consequences. As a criminal
defense attorney in Utah,
Stephen Howard has assisted clients and defended their rights from
initial police investigations through jury trial and appeal. His
experience includes cases ranging from murder to DUI, and virtually
everything in between.
Contact us today to
arrange for an initial confidential consultation, and see how we can
help you.

A Utah criminal prosecution can result in a lifetime of consequences. Beyond jail and prison, a conviction can affect many areas of life, including employment, housing, finances, family, and much more. Never plead guilty without first consulting with an experienced criminal attorney. Understanding what is at stake is the first step....
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