Laser detection of all the methods to measure the speed of cars is actually quite accurate. It works like an echo. The laser is sent out and bounces back of the car a few times. Think of it as plotting points on a graph. This is calculated to measure speed. Even though it's fairly accurate there are speed laser detector defenses that can be used to fight the ticket.

Where you need to start is to figure out what laser detector is being used specifically. This lets you check the manufacturer's information on the proper use of the equipment, what conditions work and don't work, and what the range of the unit is.

You also need to check the local jurisdictions rules for how the laser detector must be handled to make the readings legal to use in court.

Was the officer out of range? - If the officer was out of range according to the manufacturer or according to the legal rules, then the information is not accurate. This will help support your case.

Has the laser detector been calibrated recently? - Calibration of laser detectors in most areas much be done every few months to determine if they are still accurate. Sometime calibrations are not done on time making the reading inaccurate.

One issue to be careful with is to make sure that laser wasn't the only method that was used to pull you over. Some places have the officer pace you as well making the readings stronger in court since there were two methods of detection. If there were more methods, it should be noted on the ticket.

There is alot of information out there about weather conditions, dust, metal, and lights changing the readings, but for the most part these aren't really accurate claims anymore with modern devices.