Road speed limits are used in most countries to set the legal maximum or minimum speed at which road vehicles may travel on a given stretch of road.[1] In the US they have been set to protect the public.[2] Speed limits are generally indicated on a traffic sign reflecting the maximum or minimum permitted expressed as kilometres per hour (km/h) and/or miles per hour (mph). Speed limits are commonly set by the legislative bodies of national or provincial governments and enforced by national or regional police and judicial authorities.