A recent news story discussed lidar speeding tickets in the Chicago area.  In the last year or so most lidar laser tickets have been thrown out of the court.  The reason is because lidar has not been proven to be scientifically reliable for the Illinois courts.

This is important to be aware of if beating a speeding ticket, not just in Illinois or Chicago, but everywhere because the same principle applies.

Just because there is an electronic device like lidar or radar that records your car moving faster than the posted speed limit does not mean that you will legally end up having to pay fines.

Each of these units of speed measurement have certain laws and requirements that they have to meet up to.  The reason is because it would be unfair to you if the officer was using an old broken radar that was inaccurate.  

There are guidelines that units of speed measurement have to follow to be admissible in court.  It's your job the find out what those requirements are for your local area because from state to state and county to county they are different.  Check your ticket to see what type of device was used and try to look up information on that device and its legal status in your jurisdiction.

One of the most common requirement is that the machine has to be tested every three to six months to make sure the device is accurate for the reading to be used in court.