Portsmouth Speeding Instruments

In order to tell whether an individual is speeding in Portsmouth, police officers use one of three main methods: pacing, radar guns, and LIDAR equipment. While each of these methods can be accurate if used properly, speeding instruments need to be properly calibrated and maintained routinely in order to prove that they work.  When this calibration is done, officers will receive a calibration certificate that shows when, where, and by whom it was done. Typically, if they possess this in court, the judge will consider this to be enough proof to show that the way they recorded a driver’s speed was accurate and reliable.

However, if this certificate is not presented or is out of date, a Portsmouth traffic lawyer can this lack of calibration or maintenance as a defense. With this in mind, it is important to be aware of the various methods used by law enforcement and the steps an experienced attorney can take to contest their reliability or use in court.

Traffic Radar and LIDAR Tools

Radar tools along with LIDAR equipment are very commonly used to detect speeding by police officers in Portsmouth. They are considered extremely accurate and the court sees them as reliable and usually will admit the evidence unless the defendant can shed reasonable doubt on the accuracy of the reading.

The weight of these radar readings in court is very heavy in Portsmouth. Generally, the police officer doesn’t need any other evidence except for the reading from the radar instrument and the calibration certificate.


Portsmouth considers these traffic radar instruments to be extremely accurate within just a few miles per hour when officers follow the procedure as they’re required to do and they’re properly maintaining the guns routinely. Sometimes, though, people can argue that the radar instrument was somehow interfered with, depending on the particular instrument that was used.

Additionally, there are some instruments that won’t work well if there’s any precipitation at all. If a person can prove that it was a rainy day or that it was snowing or even that there were strong winds, this can sometimes be enough to show the court that the reading is not as accurate as the officer is claiming. These are not very common defenses, however, and they are difficult to use successfully.

Operator error, on the other hand, is not very common. The Portsmouth officers are very well-trained in handling the speeding instruments and are very aware of the parameters of the equipment itself. They know the distance that they need to be and they know the angle that the guns need to be pointed at to get the most accurate reading. It’s very difficult to prove that an officer did otherwise, even if that is the case.

The issues and defenses with LIDAR are very similar to the ones with radar. The defenses are the same with the strongest defense being errors or omissions on the calibration certificate.


In Virginia speeding cases, pacing is when officers determine that a vehicle may be speeding, so they follow the vehicle with their police cruiser and attempt to match the vehicle’s speed with their own. They then follow the vehicle for a determined amount of time and look at their own speedometer to determine how fast the targeted vehicle was going.

Pacing is admissible evidence of speeding in the Portsmouth court, even though it is controversial since it can be more subjective than radar and LIDAR readings.

Just like radar and LIDAR, pacing requires a calibration certificate. There is a calibration certificate that needs to be presented for the officer’s speedometer to show that the speedometer was working properly and had been calibrated within a certain period of time. However, there are still a lot of issues with this because the officer has a lot of discretion to say what the reading on the speedometer was.


The issues and defenses have to do with how subjective that way of determining speed is. Pacing is very prone to human error because it is possible that while targeting the vehicle, the officer was not matching his speed properly. In some cases, if the officer is catching up to the vehicle to pull them over, then they can read their speedometer as slightly higher than the actual speed of the vehicle, meaning the driver is being charged with a speed they were not actually going.

Another issue that could come up is if the officer’s speedometer is not properly calibrated or working well, meaning the officer is going by a speedometer that isn’t accurate and therefore he’s getting an inaccurate reading for the driver’s speed.


Because the Portsmouth officers have the paperwork and the calibration certificate that backs up how fast they allege that the driver is going, it’s not just their word up against the defendant’s in court. If a person truly believes that they were not going that fast, they need to have some kind of evidence that can go against the officer’s calibration certificate and the speeding instruments.

Since officers are routinely in court, the judges respect them and the judges believe that the officers don’t have any incentive to fabricate a speed since there really is no incentive for them to do so. On the other hand, though, the defendant will appear to have every incentive to not get a speeding ticket and they’re perfect strangers to the court. There is clearly going to be some bias in favor of the officers, and, therefore, a person needs evidence to support their statement for it to be considered credible.

The state needs to prove that the speed reading instruments work or else there would be no reason to have a calibration certificate at all. The calibration certificate is what the court accepts as evidence that the speed reading instruments are working properly. The strongest defense for radar gun readings in court, therefore, has to do with the calibration certificate. If the officer doesn’t have a calibration certificate, usually this is enough cause to have the whole case thrown out. If the officer has calibration certificate, but it’s not a true copy of it, then again, it doesn’t come in as accurate as it should be and the case is thrown out. If there’s any information on the calibration certificate that’s incorrect or missing, then this is also cause to have the case dismissed.

Other defenses are a little more complicated, but can sometimes be successful depending on the circumstances. In some cases, defendants can successfully argue that the reading of the gun was inaccurate because the gun locked onto an incorrect object. This requires a really strong cross-examination of the officer and it is not as easy as having an issue with the calibration certificate.