2.12 Lane Width: An Exificant Effect On Travel Vehicles
2.12 Lane Width
The width of a travel lane has significant effect on the driving speeds of the vehicles on that lane, and the passing vehicles on adjacent lanes. This also affects the highway capacity and level of service. The design of lane width should not only consider widths of the vehicles, but also the driving psychology. The width of a lane is measured from the pavement marking on both sides. In general, lane widths vary from of 2.7 to 3.75 m. The narrower lanes are mainly used in residential areas and in urban roads with low travel speeds (e.g., turning storage lanes, at intersections) where majority of the vehicles are passenger cars. In residential areas, lane width should not be less than 2.7 m. In urban streets, lane width of less than 3.0 m should be avoided. Larger lane widths are used when commercial vehicles are present. On a two-lane undivided highway, ideal lane width …show more content…
Each course of a pavement is a layer with specific material properties that differ from those of the other layers and that affect the overall performance of the pavement. All layers are assumed to be infinite in the horizontal plane. The subgrade, the bottom layer, is assumed to be infinite in the vertical plane as well. As the wheel of a vehicle passes over the pavement, compressive stresses are imposed in the surface course directly under the wheel. The surface course distributes the stresses over the base course, which, in turn, transmits them to the lower courses. The stresses are greatest at the top of the surface course and decrease toward the subgrade. Horizontal stresses exist below the wheel load also. In addition, the pavement is subjected to thermal stresses. Flexible pavements usually are designed by a method promulgated by the American Association of State Highway and Transportation Officials (AASHTO), or the Asphalt Institute, or the California Department of Transportation (Caltrans). (Garrabrant
The width of a travel lane has significant effect on the driving speeds of the vehicles on that lane, and the passing vehicles on adjacent lanes. This also affects the highway capacity and level of service. The design of lane width should not only consider widths of the vehicles, but also the driving psychology. The width of a lane is measured from the pavement marking on both sides. In general, lane widths vary from of 2.7 to 3.75 m. The narrower lanes are mainly used in residential areas and in urban roads with low travel speeds (e.g., turning storage lanes, at intersections) where majority of the vehicles are passenger cars. In residential areas, lane width should not be less than 2.7 m. In urban streets, lane width of less than 3.0 m should be avoided. Larger lane widths are used when commercial vehicles are present. On a two-lane undivided highway, ideal lane width …show more content…
Each course of a pavement is a layer with specific material properties that differ from those of the other layers and that affect the overall performance of the pavement. All layers are assumed to be infinite in the horizontal plane. The subgrade, the bottom layer, is assumed to be infinite in the vertical plane as well. As the wheel of a vehicle passes over the pavement, compressive stresses are imposed in the surface course directly under the wheel. The surface course distributes the stresses over the base course, which, in turn, transmits them to the lower courses. The stresses are greatest at the top of the surface course and decrease toward the subgrade. Horizontal stresses exist below the wheel load also. In addition, the pavement is subjected to thermal stresses. Flexible pavements usually are designed by a method promulgated by the American Association of State Highway and Transportation Officials (AASHTO), or the Asphalt Institute, or the California Department of Transportation (Caltrans). (Garrabrant