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 Massachusetts, the offense of speeding occurs when a driver operates a vehicle at a speed greater than the posted speed limit or at a speed that is not reasonable and prudent given the current conditions, such as road characteristics, weather, and visibility. Massachusetts General Laws Chapter 90, Section 17, outlines the rules for speed limits and the penalties for speeding violations. Penalties for speeding typically include fines, which can vary depending on how much the driver exceeded the speed limit, and may also result in the addition of demerit points to the driver's license. In Massachusetts, law enforcement officers 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 when used as evidence in speeding violations. It's important to note that local ordinances may also have specific provisions regarding speeding, and these can vary between cities and towns within the state.