Speed limit enforcement

Speed limit enforcement is the action taken by appropriately empowered authorities to check that road vehicles are complying with the speed limit in force on roads and highways. Methods used include roadside speed traps set up and operated by the police and automated roadside 'speed camera' systems which may incorporate the use of an automatic number plate recognition system. Traditionally, the police would have used stopwatches to measure the time taken for a vehicle to cover a known distance, but more recently, they have had speed guns and automated in-vehicle systems at their disposal.Many jurisdictions operate traffic violations reciprocity where non-resident drivers are treated like residents when they are stopped for a traffic offense that occurs in another jurisdiction. They also ensure that penalties such as demerit points and the ensuing increase in insurance premiums follow the driver home. The general principle of such interstate, inter-provincial, and/or international compacts is to guarantee the rule 'one license, one record.'Some groups, such as the National Motorists Association in the United States, and Motorists Against Detection in the UK claim that systems are used primarily as a source of revenue rather than to enforce traffic rules for the declared objectives. However, a meta-analysis of studies finds automated ticketing machines that enforce speed limits may have reduced the number of traffic injuries and deaths.