Tuesday, June 15, 2010

Police Do Not Have a Speeding Ticket Quota

A friend of mine is a cop and I’ve been lucky enough to go on a few ride-along trips with him. It’s pretty interesting to get a firsthand look at the job of a police officer. It gives you a lot of respect for the tough job they do.

When they’re not responding to calls, they’re doing paperwork and enforcing speed limits. On one particular ride-along, we spent a couple of hours trying to catch speeders. This was of great interest to me since I am a chronic speeder.

The first thing I wanted to know, what is the deal with quotas?

He said they don’t have a quota. Although, he added that if he didn’t write any tickets then it wouldn’t look like he was doing his job. Also, there are some cops who are trying to get promoted and write a lot of tickets, so if the other cops don’t write a fair amount of tickets then they come across as slackers. So, while there isn’t an official quota, these are the reasons why cops are driven to write tickets.

There are many tools that cops use to catch speeders. There are two speed measuring technologies, doppler radar and laser (aka Lidar, Ladar and “Laser Radar”). Doppler radar technology is the same technology that is used by meteorologists to analyze clouds and predict weather patterns. It’s also used at many stores to control automatic doors. Doppler radar units for law enforcement, come in many varieties: hand-held, vehicle mounted and automated photo-radar.

Laser speed tools for police only come in hand-held models. Although, similar technology is also used by the military and airports to accurately monitor air traffic movement. In fact, there are many other uses for this technology too. One of the newer uses is in wind power farms to measure incoming wind so the turbine blades can be adjusted for best performance and to prevent damage to the equipment in heavy winds.

Both, doppler and laser technologies have advantages and disadvantages. Laser speed guns are extremely accurate and are effective at great distances. They’re also very fast, which is bad for radar detector users — laser detection doesn’t give much time to slow down before your speed is detected. Because they are so accurate, they are only available as hand-held units.

Doppler radar systems are available as hand-held units and vehicle mounted systems. Doppler radar is not very accurate, it can have a wide beam spread that can be as wide as four lanes of traffic at 200 meters (650 feet). That’s great when there are few cars on the road, you can’t miss. It also means the technology can be mounted in the front and rear windows for automatic readings as the officer is driving around — the units will automatically read the speed of traffic in front of and behind the vehicle.

Because the beam covers so many lanes, it means that many vehicles can be picked up at once. If the officer is not properly trained, it is easy to make an error and suspect the wrong vehicle of speeding. Because of the way the technology works, larger and faster objects often take precedence in speed readings. When the large object is a nearby airplane, the 300 mph reading is an obvious error. When the object is a semi truck in the opposite lane traveling faster than a small car in oncoming traffic, the 20 mph difference may be less obvious and lead to officer error.

Neither radar technology works in a perpendicular manner, so if you’re traveling from side to side in front of a speed unit, it cannot read your speed. They only work when you are either getting closer or further away. When a speed reading is possible, the most accurate reading is when the device is directly in front or behind your car. The further to the side the speed gun, the lower the reading will be. That’s why you will often see speed traps on corners of the highway, this allows the officer to get directly in front of your car and achieve the highest and most accurate speed reading. The element of surprise is also important, anytime you come over the crest of a hill, look at the bottom of the hill for a speed trap.

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