How Police Catch Speeders

Have you ever wondered how police catch drivers who are speeding or committing traffic violations? The thought has probably crossed your mind if you’ve been pulled over after being a little too heavy-footed on the road. And unfortunately, that mistake can carry a hefty fine—the average cost of a speeding ticket, including fees, is $152 according to Statistic Brain. Plus, choosing the convenience of a fast journey over safe driving could have serious consequences for you and for drivers around you.

So how do cops catch speeders? Here’s what you need to know about the radar guns, laser guns, aerial monitoring methods and speed cameras that are used to help keep roads safe.

How Radar Guns Work

Radar guns are used to almost instantly measure the speed of a vehicle on the road. When aimed at a moving object, a radar gun (also called a “speed gun”) emits radio waves that bounce off of cars and detect their speed. The result of the radar’s read on a radar gun is either a high, steady tone (indicating a clear reading) coming from the gun’s speakers, or a low, unsteady, raspy tone (indicating a weak reading). A Police Magazine resource states that the best targets for a radar gun “are, in order, a license plate, a headlight, and a chrome bumper. This is because they are highly reflective surfaces.”

How Laser Guns Work

According to HowStuffWorks, “a laser speed gun measures the round-trip time for light to reach a car and reflect back.” This time is then used to accurately calculate the speed of a moving vehicle.

About Aerial Monitoring

Aerial detection of speeders is usually achieved when police paint lines along a stretch of road to mark the beginning and end of a certain distance. According to interviews collected by CNN, police in a helicopter or plane will then clock the time it takes for a driver to travel that stretch. If that time is shorter than it should be, that means the driver is speeding, and the cop doing the aerial monitoring will radio a police car on the ground, which might be parked a mile or so away from the area being monitored.

How Speed Cameras Work

If you’ve ever sped past a lamppost or phone pole and received a ticket in the mail a few days or weeks later, you’ve been caught by a speed camera. However, while they might seem like an annoying method of law enforcement, according to research from the NCJRS, “Photo enforcement has led to a dramatic reduction in traffic fatalities and injuries.” Information from the Maryland SafeZones program states that a speed camera takes “a series of photographs [that] are recorded to document vehicles traveling at or above a determined speed threshold. The date, time, and location of the violation, as well as the speed and license plate of the violator’s vehicle are recorded. Following the proper identification of the registered owner of the vehicle using the license plate number, the registered owner is mailed a citation, which includes the violation photos and the vehicle speed.”

Staying Safe and Avoiding Speed

What extra precautions can you take to make sure you stick to the speed limit? The most obvious is to keep an eye on your speedometer. However, this can feel difficult if you’re on a long road trip and you have to switch between high-speed highways and low-speed, small town streets. Slowing from 70 mph to 50 mph, and to 30 mph can lead to a speed trap-caused ticket if you’re not careful.

If you’re driving alone, be on the lookout for speed limit signs. If you’re traveling with friends or family members, ask them to help keep an eye out for speed changes. If you are pulled over, make sure you have your license and proof of insurance ready to present to the police officer. (Having the card for your affordable auto insurance available could keep you from having to pay additional fines or worry about things like a suspended license that could require you to purchase insurance with an SR-22.)

Just remember that at the end of the day, those extra five minutes you’re aiming to save when you speed could actually cost you a good chunk of your hard-earned money.