How Wide is a 4-Lane Road?
1 Answers
The subgrade width of a bidirectional four-lane ordinary highway is 24.5 meters. For a bidirectional four-lane expressway, the subgrade width is 26 meters. Depending on the nature of the lane, its grade, and the design speed, the width of the lane varies, generally ranging between 2.4 to 4.2 meters. Lane width typically ranges from 2.4 to 4.2 meters. Generally, the higher the design speed of the road, the more likely the lane width is to increase. However, the standard width usually falls between 3.0 to 3.75 meters, with 3.5 meters being the most common. Excessively wide lanes can lead to vehicles driving side by side within the same lane, while lanes that are too narrow may cause vehicles to veer out of the lane. Therefore, it is not recommended for lane width to exceed 3.5 meters or be less than 2.8 meters. However, for national highways, provincial highways, first-class roads, and second-class roads (excluding second-class highways), each lane is 3.75 meters wide. When necessary, an ultra-wide non-motorized vehicle lane of at least 3.5 meters and a sidewalk of at least 4 meters must be established. Each lane on an expressway is also 3.75 meters wide, with additional requirements for green belts, shoulders, emergency lanes, and emergency stopping strips ranging from 1.5 to 3.5 meters.
