Colorado authorizes low-speed vehicles on portions of public roads
Effective August 2009, Colorado will join 42 other states and the District of Columbia in authorizing low-speed vehicles on roads with a posted limit of 35 mph or lower. The law restricts low-speed vehicles from traveling faster than 25 mph. Previously, low-speed vehicles were permitted in Colorado only by local option.
To compare low-speed vehicle laws in all states http://www.iihs.org/laws/LowSpeedVehicles.aspx