With the advancement of technology, more police departments are using technology to their advantage concerning probable cause traffic stops (Tate) in relationship to speed measuring devices such as radar, laser/lidar, pacing, gap timing and traffic control devices (stop signs, traffic lights and pavement markings).
In essence, the police officer uses traffic violations (tickets) as an excuse to make a traffic stop and comply with the fourth amendment of the Constitutional; probable cause traffic stop and/or reasonable suspicion.
In order for the best possible defense against a probable cause traffic ticket (Tate), retain the correct expert / expert witness. That expert witness should have qualifications such as being an engineer that is certified instructor / operator in speed measuring devices as well as being efficient in traffic control devices.