A report from the transportation Research Board's National Cooperative Highway Research Program presents recommendations for bicycle lane widths for various roadway and traffic characteristics that include traffic volume, vehicle mix such as percent of trucks, lane width, total roadway width, and both the presence and absence of on-street parking.

Aimed at traffic and design engineers in areas where bicycle lanes are being considered and implemented, its conclusions are most applicable to urban and suburban roadways with level grade and a posted speed limit of 30 mph. Its findings should be used cautiously for the design of roadways with motor vehicle speeds outside of the range of 25 to 35 mph, and in particular for higher-speed roadways.