Although curbs do not have a significant re-directional capacity, curbs are intended to discourage motorists from deliberately leaving the roadway.

Curb designs are classified as vertical or mountable.

Mountable curbs, especially those with heights of 4-in or less, can be traversed by a motorist when necessary. A preferable height for mountable curbs at some locations may be 4-in or less because higher curbs may drag the underside of some vehicles.

Curbs are used primarily on frontage roads, crossroads, and low-speed streets in rural town, urban and urban core contexts. I

n general, curbs are not desirable along highspeed roadways.

They should not be used with high-speed through traffic lanes or ramp areas except at the outer edge of the shoulder where needed for drainage, in which case they should be of the mountable type, preferably 4-in or less in height.

Refer to the current for illustrations on the various TxDOT standard curb types.

Curbs are not generally used in rural context due to high speeds. If curbs are provided, they must be mountable and should not be closer to the traveled way than the outer edge of the shoulder.

Curbs may be used in a suburban context. Mountable curb must be used if the design speed is 50 mph or greater.

Due to limited ROW availability usually associated with these contexts, curbs will generally be used instead of shoulders.

Curb offsets can vary from 1 to 2-ft. If a curb offset is not provided a design waiver will be required. The curb offset is always measured from the face of curb whether it is a monolithic curb section or a curb and gutter section.

See for additional offset requirements for bicycle facilities.

Both variations of curb offsets are illustrated in .