5-1-1, initially designated for road weather information, is a transportation and traffic information telephone hotline in some regions of the United States and Canada. Travelers can dial the three-digit telephone number 5-1-1 on traditional landline telephones and most mobile phones. It is an N11 code of the North American Numbering Plan that are used for special services. The number code has also extended to be the default name of many state/provincial transportation department road conditions websites, such as Wisconsin's site.
As of March 2001, at least 300 telephone numbers existed for travel information systems in the United States. To overcome the confusion caused by this array of numbers, the United States Department of Transportation (USDOT) petitioned the Federal Communications Commission (FCC) for a national assignment of a single three-digit N11 dialing code. On July 21, 2000, the FCC assigned 511 as a nationwide telephone number for ITS traveler information, along with 2-1-1 for social services. Its use is being promoted by the USDOT's Intelligent Transport Systems initiative.
The first 511 traveler information system to launch was in the Cincinnati-Northern Kentucky metropolitan area in June 2001.
The first statewide 511 traveler information system was launched across the state of Nebraska in October 2001.