There are always issues that come up with traffic radar devices. You can show that it hadn’t been properly calibrated in the legally necessary amount of time before its use. You can show that it wasn’t tested for accuracy both before and after the officer’s shift as required to be admissible, and in rare cases you can show that although it had been tested and calibrated, the officer was using it wrong or wasn’t properly trained in how to use it.
Sometimes you can also show that the sun or objects on the roads interfered with the radar reading and led to false results. These are all possible defenses and ways to show the traffic device wasn’t working correctly, but the traffic radar device is typically given a lot of weight by the judge and it is very difficult to show that it was working improperly.
They are tested for accuracy both before and after an officers shift and are calibrate every six months so they tend to be fairly accurate. However, more importantly than their actual accuracy is the fact that the radar readings are admissible in court and are given great weight by the judge in determining your guilt or innocence. Their actual accuracy is of course important, but from a more practical viewpoint, they are thought to be accurate by judges, so they are very strong evidence of your guilt in a traffic or reckless driving case.
It isn’t common, per se, but it can happen. It is often difficult to really know how often it there is operator error because usually there is just one police officer in a car running radar and they think they are operating it properly and will testify to that effect. So, even if operator is more common than you would think, it is difficult to show that to a judge. In general, like any other human endeavor, there can be error. It’s just a matter of defense attorney showing that there was operator error to the court to actually help your case and that can be difficult to do.
Lidar is a laser device very similar to radar. It is a probably slightly more accurate than radar and it is given a lot of weight by judges. There are possible defenses such as whether it was calibrated in the prior 6 months, whether it was tested before and after the shift, whether there was operator error, whether some object got in the way of measuring the vehicle’s speed in between the laser device and the vehicle, but for the most part it is pretty strong evidence of the car’s speed. So, although there are numerous defenses to readings from the laser device, it does tend to be fairly accurate if maintained, tests, and used properly.
Yes, the court does need to show it’s accurate because it is the state’s burden to prove your guilt beyond a reasonable doubt. To show that it the instrument is accurate, the state needs to put forth evidence in court that the device was properly calibrated and had been tested before and after the officer’s shift to show that it was working properly on the day in question. They do that in numerous ways, but mainly through the officer’s testimony.
Pacing is when a police officer gets in behind your vehicle in his or her own vehicle and measures your rate of speed in comparison to their own vehicle’s rate of speed. To be able to get a speed reading based upon pace somebody, the officer needs to the driver behind your vehicle at a constant distance. They also need to be looking at the speedometer on their car and at the same time try to determine whether your vehicle is going either faster than their car, slower than their car, or at the same rate of speed.
For example, if the police officer is traveling 60 mph and the car in front of him or her is pulling away from their police car, they can infer that your car is traveling in excess of 60 mph. In order for the police to show that the pacing reading is correct and accurate, they have to show that their speedometer was calibrated and they also have to show that they were traveling at a certain distance behind the vehicle for a certain amount of time. Their training and experience in the visual estimation of speed is almost extremely important when proving a “pace”-based speeding or reckless driving conviction in court.