Find out all you need to know about a speedometer calibration.

What is a Speedometer Calibration?

speedometer calibration


Speedometer calibration tests the accuracy of your speedometer. Wheel sizes, tire diameter, and tire height impact miles per hour. Virginia law § 46.2-942 governs the admissibility of speedometer calibrations. A judge or jury MUST consider a notarized copy of the calibration test in determining guilt or innocence. In addition, the speedometer calibration must be considered in fixing the punishment. A dynamometer, or “dyno” is used to measure the accuracy of the speedometer at different speed intervals. Any Virginia speedometer calibration must be sworn or notarized.

Every week I watch people present documents in court that are not true calibrations. Even some attorneys try to do this. Virginia speedometer calibrations must be sworn. That means a notary must swear the certificate is a true and accurate certificate of the results. Virginia calibrations test the speedometer accuracy at different speed intervals. They usually look like a chart, or a table.

Many people falsely believe they can take their vehicle to a repair shop and present the repair bill as a “calibration.” In reality, it is just a repair bill and not a calibration. True, the shop may say they replaced your speedometer cluster or instrument cluster. It may say they did work on your speedometer. The truth is that in every court I practice these repair bills are given no weight. These are not actual calibrations that test the speedometer.

Speedometer Calibration Cost

Speedometer calibration cost will vary depending on where you take your vehicle to get calibrated. Most speedometer calibrations will cost about $50-100 but some places charge more. You do not necessarily get what you pay for when it comes to calibrations. Calibrations checks should not take a lot of time. The auto body shop will hook your vehicle up to the dynamometer, and measure the accuracy of your speedometer. They measure it at different speed intervals, and the shop notes any differences between your vehicle’s speedometer reading and the correct speed.

Should You Get a Speedometer Calibration?

Whether you should get a speedometer calibration or not depends on what court you are in. Where did you get your ticket? Every judge is different on how they treat calibrations. Some judges give calibrations a lot of weight, and some give them almost no weight at all. Remember, the law just says courts must consider them. It does not say what weight the judge or jury must give them. Therefore, before you invest your time and money into a speedometer calibration, you should know whether or not it will help.

It is important to know the judge for your particular case. I know one lawyer who recommends that his clients get calibrations on EVERY case. This is a poor strategy. Why would you refer a client to get a calibration unless it could make a difference? On top of the speedometer calibration cost, it takes time and effort to get calibrations. I don’t recommend them UNLESS there is a chance it would benefit my client.

Keep in mind the potential for future tickets. If the speed of the car is not registering correct you might get speeding tickets. You may not be able to follow the speed limit if the speedometer is reading incorrect. Traffic court is not the only reason to get a calibration. You need to make sure you can trust your speedometer. Accurate speedometers read the miles per hour correctly.

Where to Get Speedometer Calibration?

Any good traffic lawyers know where to get a speedometer calibration. In my experience, many calibration shops operate in a negligent manner. Consider the following true case:

“When Dana Schrad’s son got a speeding ticket several years ago, she knew they needed to get the car’s speedometer calibrated.Her son drove the older-model Ford on the highway and Schrad followed in her vehicle, pacing his car to measure the speed. They discovered that the speedometer on the Ford was off by at least 5 mph. Yet two separate professional calibrations later found nothing was wrong with the car, said Schrad, who is executive director of the Virginia Association of Chiefs of Police.”

This case illustrates that is is important to know where to get speedometer calibrated. If you don’t know where to get a speedometer calibration, you may very well be wasting your money. In my opinion, every speedometer will have some variance. Speedometer accuracy is impacted by tire size, tire inflation, and even the tire tread. Temperature and speed can impact tire inflation, which will impact the accuracy of your speedometer. I am skeptical of any speedometer calibration shop that provides a certificate that is 100 percent accurate at every speed. There should be some variation, even if it’s small.

Be careful where you get your speedometer calibrated. Where to get your speedometer calibration done is a trade secret. I give my clients legal advice where to get calibrations. Reckless driving and speeding  The shops that I have vetted over the years seem to do a very good job. I have never had any issues. The calibrations are done professionally and I will continue to recommend these shops as long as that is the case.

How to Use a Speedometer Calibration in Court

  1. Determine whether the speedometer is accurate or not: Speedometer calibration certificates can be helpful.  If your speedometer reads HIGHER than the actual speed that doesn’t help. If your speedometer reads LOWER than the actual speed, it MAY help.
  2. Determine if a calibration will help or not: Every court is different. I know judges where speedometer calibrations help. I know others where it really doesn’t help. And still others it will help at different speeds. Speedometer calibrations help locate inaccurate speedometers.
  3. Determine how to use your calibration: Speedometer calibrations are usually helpful to MINIMIZE the punishment. It can help take a reckless driving charge or speeding ticket to non moving violations. That usually avoids points.

Your insurance will often increase because of a traffic stop. Speedometer checks help even with recently purchased vehicles. The gear ratios could be off. Auto repairs, tire diameter, tire height, and tire size impact speedometer accuracy. Wheel sizes impact miles per hour. If it makes sense, bring your vehicle in for a speedometer check.

Speedometer Calibration Summary

Getting a traffic ticket due to a traffic stop is not fun. You may want to check the accuracy of your speedometer if:

  1. you have a speeding charge
  2. you are charged with reckless driving by speed

Reckless driving by speed is a criminal misdemeanor. You should avoid it at all costs. Speedometer calibration certificates can help reduce reckless driving and speeding tickets. They tell whether the speed of the car is reading correct. Inaccurate speedometers result in speeding tickets. With a speedometer calibration, you can often reduce a charge to nonmoving violations. Nonmoving violations have not points. That will save you a lot in insurance.

Call an expert traffic lawyer first. See if a speedometer calibration may help. Get specialized legal advice though. Many lawyers do not know the law in this area. If a calibration will help, then find out where to get it. A good lawyer will give you an idea about speedometer calibration cost. In addition, they will tell you if the cost is worth it. We practice in the following locations:


Contact Us

Contact Leavitt & Martin, PLLC. • Free Initial Consultations

Our office hours are 9 a.m. to 5 p.m., Monday through Friday, but you can call anytime, 24 hours a day, and we can often make weekend and evening appointments available.



116-B Walton Park Ln.
Midlothian, VA 23114


312 South Main Street
Emporia, Virginia 23847

Connect with Us