At this point in the history of highway driving, everyone knows that the most popular police speed traps employ good old-fashioned radar. In this scenario, of course, a police officer will stealthily park his or her police car out of the view of oncoming motorists, perhaps under an overpass, in a ditch in the middle of the freeway or behind a billboard. Then, the police officer will flip on a radar unit that transmits radio waves at particular frequencies. The waves bounce off the target, in this case, a car that the police officer believes to be speeding, and those waves are then picked up by a receiver. The shift in frequencies tells the police officer how fast the car is going.
In recent years, however, more and more police departments have been using laser guns, either in addition to or in place of radar. "We began using the laser guns about 10 years ago," says one former police officer from a Midwestern state, who asked that we not use his real name. We'll call him Jack.
"They're actually more efficient than radar. The laser guns can pinpoint a specific car much more accurately," says Jack. The other advantage to using a laser gun is that the laser light can't be detected by those pricey radar detectors often used by drivers who would really rather speed with impunity - or is that immunity?
One of the more sly methods that police officers use to detect hot-footing motorists is aerial detection. Typically, this is done by painting white lines at either end of a stretch of highway – usually a quarter-mile or half-mile long. A police officer in a helicopter or plane will time how long it takes the driver to travel the distance between the lines. "That allows the spotter to calculate the driver's speed," says Jack. "He can then just call ahead to an officer in a patrol car on the ground that's another two or three miles down the highway, and tell him green Taurus, left lane."
In another aerial speed-detection technique, the police officer simply does a visual estimate of the speed of the cars below, and compares it to the "ground speed" of the helicopter based on using visual targets along the highway.
There is yet another method to catch speeders, and it doesn't require a police officer to be physically present at the speed trap location. Speed cameras are attached to lampposts or telephone poles and programmed to snap photos of speeding vehicles. While speed cameras have been employed on a comparatively limited basis in the United States, they've been used more extensively in Europe, Canada and other parts of the world for more than thirty years, according to the Insurance Institute for Highway Safety.
This method can deliver a delayed shock to the system of a speeder, since the driver isn't pulled over on the spot. He won't know that he's gotten a speeding ticket until he receives the eye-popping infraction notice in the mail. If you have a problem controlling your tongue in the presence of a police officer who has just written you a $200 speeding ticket, this ticketing system might be your favorite. But if you prefer discussing the ticket and related circumstances – or ask for a warning – you (obviously) won't have that opportunity until reaching court.
Sometimes, the best enforcement of speed limits is a not-so-subtle reminder in the form of the electronic speed boards you see alongside a highway that flash big, bright, white-hot numbers in your face to let you know how fast you're going. These boards also employ radar. "The radar unit sees the target, transmits the radio waves, they bounce back, and tell the drivers how fast they're going," says Jack. "We used to think of those speed boards as being more of an 'awareness program,' because they remind people of their speed. A lot of drivers really don't know how fast they're going, so these speed boards essentially are a means of urging voluntary compliance."
And, according to Jack, that's the main point of enforcing speed limits via speed traps. While traffic fines do augment revenues for the city, state or county, that's not why speed traps are set up, says Jack. "That's a myth that we had quotas on how many traffic tickets we had to write in a single month. We just want people to obey the speed limit, because it's for their own safety," says Jack. "The main reason for setting up a speed trap, whether radar, laser or aerial monitoring, is simply to encourage voluntary compliance of the law. And we never cared if someone called in a radio station and says, 'Oh, there's a speed trap set up on such-and-such a road,' because it achieved the same result as a motorist seeing a cop writing someone a ticket. It got people to slow down."
Ed. Note: Based on reader reaction to the statement about quotas we consulted a second police officer, a highway patrolman in the Southwest, and he offered the same answer, "We didn't have quotas, either." said Carl, whose name was changed for reasons of anonymity. "In my experience, speeding-citation revenues were not a great portion of municipal revenue. Speed enforcement is for the benefit of the public – to reduce the number of accidents, especially fatal accidents. Unfortunately, drivers think they know best what they should be able to do, and choose convenience over caution." It is possible quotas are enforced in some states or districts and not in others, like Jack's or Carl's.
If you'd enjoy reading more on this topic:
You Got Caught Speeding Well Over The Limit. Now What?
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