The infraction or offense of speeding is committed when the driver of a motor vehicle exceeds the posted speed limit or exceeds the speed limit that is reasonable and prudent under the circumstances or conditions—such as the road (straight, curved, wet, dry, icy, flat, hilly); the weather (clear, foggy, raining, snowing); and the visibility (smoke from a grass fire or a tractor trailer obstructing the view).

Speeding laws (and enforcement) vary from state to state and among cities and towns (local ordinances) and are usually located in a state’s statutes. The penalty for speeding is usually a fine and demerit points added to the driver’s license or driving record.

To measure the speed of a moving vehicle and issue speeding tickets, police officers generally use radar guns that rely on radio signals and the Doppler Effect, or Light Detection and Ranging (LIDAR) technology that relies on lasers rather than radio waves. These devices require training on their proper use and regular calibration to be accurate.

In North Carolina (NC), speeding is defined as driving at a speed greater than the posted limit or at a speed that is not reasonable and prudent under the existing conditions, which include factors such as the type of road, weather, and visibility. North Carolina General Statutes (NCGS) outline the regulations and penalties associated with speeding. Penalties for speeding can include fines, court costs, and points on the driver's license, which can lead to increased insurance rates and, with the accumulation of enough points, license suspension. The amount of the fine and the number of points can vary depending on how much the driver exceeded the speed limit and whether it was in a school or work zone. Law enforcement officers in NC use radar and LIDAR technology to measure vehicle speeds. These devices are subject to specific requirements regarding their use, training, and calibration to ensure accuracy and the validity of the evidence in court. It's important to note that local ordinances may also apply and can affect the enforcement and penalties for speeding violations.