Criminal Law

Common Defenses for Fighting a Speeding Ticket

By John McCurley, Attorney
A few basic lines of defense for contesting a speeding ticket.

Most motorists will at some point be cited for breaking the speed limit. If it happens to you, you’ll first need to decide whether to contest the ticket or just pay it and move on. You might also want to consider whether it’s worth it for you to hire a traffic attorney.

Before making either of these decisions, however, you might want to know the chances of beating your ticket in court. Unfortunately, it’s tough to say. But knowing a little about some of the more common speeding-ticket defenses might help you decide what to do.

(To learn more about contesting a speeding ticket in court, see Fighting a Speeding Ticket.)

Types of Excessive-Speed Laws

The available defenses depend on what type of speed law you were cited for violating. Speed-limit laws generally fall into one of three categories:

  • “absolute”
  • “presumed,” “presumptive,” or “prima facie,” and
  • “basic.”

Absolute speed limits are simple: If you drive faster than the posted limit, you’ve broken the law. If you exceed a prima facie speed limit, on the other hand, the court will presume you’re guilty of speeding but give you a chance to prove otherwise. By showing that—despite driving faster than the prima facie limit—you were driving a safe speed, you can get off the hook. With basic speed limits, the court decides guilt based only on whether you were going a safe speed—no presumptions or set limits are involved.

(Read more about the different types of excessive speed laws.)

Common Defenses

The available defenses depend on the circumstances of your case. The law varies by state, and the facts of each case are different. It’s always best to talk to a qualified traffic attorney to find out what your best options are. But here’s some basic information about some of the more common speeding-ticket defenses.

Safe Speed

You can defend against presumptive and basic speeding violations by proving you were driving a safe speed. The basic idea is to show the road and weather conditions made it safe to be driving whatever speed you were going.

Example: Roger was driving to church Sunday morning. The sun was at his back and there wasn’t a cloud in the sky. Being that Roger lived in a fairly rural area, there were hardly any other cars on the road. As he approached his destination, Roger was stopped for driving 28 miles per hour on a street with a 25 mile-per-hour presumptive limit. Roger will likely have a successful safe-speed defense because weather conditions were favorable, traffic was light, and he was going only three miles per hour faster than the presumed limit.

Example: Intense rain storms knocked out Hank’s power Sunday night, so his alarm didn’t go off Monday morning. By the time Hank woke up, he had only 15 minutes to get to work. He quickly threw on some clothes, jumped in his car, and sped off. Traffic was moving slowly because of the rain, so Hank tried to get ahead by weaving through the cars. Just when Hank thought he was home free, a police officer pulled him over for going 45 miles per hour in a presumed 25-miles-per-hour zone. A judge won’t likely buy Hank’s safe-speed argument; Hank was breaking the presumptive limit by 20 miles per hour and road, and weather conditions were poor (rain and heavy traffic) for driving fast.

Challenging the Officer’s Perception

In some cases—rather than using radar or some other speed-measuring device—the officer estimates the driver’s speed. When a citation is based on an officer’s estimate, defenses often involve challenging the officer’s ability to perceive and assess the speed accurately.

Two common methods officers use to estimate speed are “pacing” and “visual estimates.”

Pacing. With pacing, the officer drives in the same direction as the motorist and attempts to match the motorist’s speed. The officer then estimates how fast the motorist was going based on what the patrol car’s speedometer says.

Defending against a pacing estimate typically involves trying to show that the officer was too far away or didn’t pace the motorist for long enough for the method to be reliable.

Visual estimates. “Visual estimate” generally refers to when an officer—while at a standstill—estimates how fast a car is going as it passes. Though it might seem like a rough method, many courts accept visual estimates as evidence of speed.

Challenging a visual estimate might involve questioning an officer about visual-estimate training or lack thereof. Some courts won’t allow this kind of evidence unless the officer has been trained and certified in visual estimation. Another line of defense might exist if the officer’s vantage point would’ve made it difficult to clearly see the vehicle as it passed.

Radar and Lidar Defenses

Generally, speed-measuring devices like RADAR and LIDAR are more accurate than officer estimates of speed. But there are still ways to attack RADAR and LIDAR measurements.

Calibration and maintenance. Speed-measuring devices must be in proper working order to give accurate measurements. And to continue working properly, certain upkeep is required. Some court won’t accept RADAR or LIDAR results as evidence of speed if the machine hasn’t been calibrated and maintenanced properly.

False readings. Even if a device is working correctly, it doesn’t necessarily mean the reading was right. To measure speed with RADAR or LIDAR, the officer aims the device at a particular vehicle; so the accuracy of the measurement depends on the officer’s aim. If there are other cars driving close to the target vehicle, the officer might accidentally get a reading from one of the neighboring cars.

Questions for an Attorney

  • Can rain or snow affect the accuracy of a RADAR of LIDAR?
  • How does the “cosine effect” contribute to RADAR and LIDAR error?
  • Is it worth it to fight a ticket if I don’t have any defenses?
  • Is there a way to find out before my trial whether the RADAR or LIDAR was properly calibrated and maintenanced?
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