A Bicycle Ambassador is a bicycling

Cycling

Cycling, also called bicycling or biking, is the use of bicycles for transport, recreation, or for sport. Persons engaged in cycling are cyclists or bicyclists...

 advocate, or member of team of advocates, tasked with promoting bicycling in a community. Such advocates are traditionally hired by the city government and networked extensively with other municipal offices whose activities effect cycling. Early programs began in Toronto

Cycling in Toronto

Toronto, like many North American cities, has slowly been improving its cycling infrastructure. At the same time the number of cyclists has been increasing progressively, particularly in the core, as cycling conditions improve, a cycling culture strengthens and alternatives such as automobiles are...

 in the late nineteen nineties. Other cities picked it up over the following decade, Chicago being the largest. Portland Oregon, San Francisco California, Seattle, Washington, Arlington, Virginia also have programs. Philadelphia and Washington DC began programs most recently. Some programs are entirely youth focused, while others become a de facto part of the city Department of Transportation

Department of Transportation

The Department of Transportation is the most common name for a government agency in North America devoted to transportation. The largest is the United States Department of Transportation, which oversees interstate travel. All U.S. states, Canadian provinces, and many local agencies also have...

or other government agency.