How wide is a standard traffic lane?

[VanClayton]

For a two-way four-lane road, it's 2*7.5 meters; for a two-way six-lane road, it's 2*11.25 meters; and for a two-way eight-lane road, it's 2*15 meters. There are national standards for the width of each motor vehicle lane on highways. For multi-lane highways above grade three, the width of each motor vehicle lane is 3.5~3.75 meters. Highways and first-class roads generally have four lanes, and the number of lanes can be increased to an even number when necessary. For secondary roads in plain or hilly areas with minimal slow traffic or where slow traffic is separated, the width is 7 meters. For sections with mixed traffic, the width is generally 9 meters; when the mixed traffic volume is large and it's difficult to separate slow lanes, the carriageway width can be widened to 12 meters, with lines dividing the fast and slow lanes.