5.1.6 Travel Lane Width and Number of Lanes

Travel lane widths may vary from 10 to 12-ft depending on the context classification of the facility and the future ADT.
Minimum width of new or widened structures should accommodate the approach roadway width including shoulders.
5.1.6.1 Rural
Rural contexts should generally provide 12-ft lanes, especially on roads where the ADT > 2000 and substantial truck volumes are present or agricultural equipment frequently uses the road. For roadways with ADT between 400 and 2,000 and a design speed ≤ 50 mph a minimum of 11-ft lanes must be used. On very low-volume roadways (lower than 400 VPD), 10-ft lanes may be used.
Two travel lanes should be provided on local roads in rural areas. Additional lanes may be needed based on operational analysis.
5.1.6.2 Rural Town, Suburban, Urban and Urban Core
Rural town, suburban, urban, and urban core contexts commonly use 11 to 12-ft lane widths. In industrial areas, 12-ft lane widths should be provided. Industrial areas with constrained ROW may use 11-ft lane widths. In nonindustrial areas with constrained ROW, 10-ft lane width may be used. 9-ft minimum lane width may be used in residential areas.
Refer to
AASHTO’s A Policy on Geometric Design of Highways and Streets
for guidance on number of lane widths in these contexts.