Column: Ask a Trooper, by Jacalyn Sticha

What is radar and is it accurate? What do you think of radar detectors?

Police radar works on the Doppler principle; a change in the frequency of a signal in direct proportion to the speed of an object. The Doppler principle was discovered in 1842 by an Austrian physicist named Christian Johann Doppler, and has been used to measure speed since 1948. The police radar transmits a signal at the target at a known frequency and the return signal is converted into miles per hour.

Once a speed-reading is delivered, which is about the same time the radar detector is alerting the driver, it is likely already a done deal. We can often tell who has a detector because of the rapid decline in the speed of the targeted vehicle.

My experience has shown that motorists who use radar detectors may be stopped more frequently and possibly may have lengthier driving records. A false sense of security, initially, has them speeding more often and at higher rates. A radar detector in a vehicle is not as common as you may think; drivers who use them seem to get rid of them quickly.

The notes written on a speed citation by an officer will have the information about radar detector use. These are the notes available to the court, attorneys and the judges. “They” will know that the violator had a device that they believed would help them break the law and remain undetected.

Another way of calculating speed is using time and distance. This can be done with aircraft and a trooper in a squad car. The speed is calculated using the time it takes a vehicle to travel between two measured marks. No frequency signal is used therefore no detectors are set off.

These two methods are extremely accurate when properly used by well-trained law enforcement personnel.

Did you know?

Here are facts on impaired driving in Minnesota.

A little history:

The state’s first DWI Law enacted was in 1911.

When baby boomers began to drive in the 1960s more than 60 percent percent of traffic deaths were due to drinking and driving. This started to decrease in the 1980s. Currently about 30 percent of all fatalities are alcohol-related.

The earliest record of traffic deaths was in 1910, with 23 fatalities. Systematic record keeping on crashes started much later in the 1930s.

Who and how many:

Over 570,191 Minnesotans (10.7 percent) have one or more DWIs on record. Of licensed drivers in the state, 1 in 7 have one or more incidents on record, 1 in 17 have two or more and 1 in 30 have three or more. Startling, 1,265 Minnesotans have 10 or more impaired driving incidents.

In 2011, there were 29,257 impaired driving incidents, with 1,903 being underage drivers.

In 55 percent of impaired driving incidents the violators are 20- to 34-year-olds. Males committed 73 percent of the incidents.

Of all violators, 60 percent had no prior alcohol incidents on record, leaving 40 percent as re-offenders. Of those who incur a second violation, half of them will go on to a third, half with a third incident will incur a fourth. Impaired driving incidents remain permanently on a violator’s record.

Where and when:

Mahnomen, Mille Lacs, Clearwater, Cass and Becker Counties have the highest percentage of impaired driving incidents on record and Stevens, Rock, Lincoln, Carver and Washington have the lowest.

Fridays account for 16 percent of all alcohol incidents, Saturdays for 27 percent and, finally, Sunday for 23 percent.

(Information taken from Minnesota Motor Vehicle Impaired Driving Facts; 2011, Minnesota Office of Traffic Safety.)

 

Jacalyn Sticha is a sergeant with the Minnesota State Patrol.