There are two types of curbs: barrier and mountable. Both in urban and suburban environments curbs serve functions such as drainage control, roadway edge delineation, and right-of-way reduction.

Used primarily in urban and suburban environments, curbs can serve some or all of the following functions:

• Drainage control
• Roadway edge delineation
• Right-of-way reduction
• Aesthetics
• Delineation of pedestrian walkways
• Reduction of maintenance operations
• Assistance in roadside development.

There are basically two types of curbs: barrier and mountable. Flexibility in the use of either type is a handy tool for a highway designer when defining the cross section of an improvement project. Barrier-type curbs are not, however, recommended for projects with design speeds above 65 km/h (40 mph).

Curbs can be constructed from a variety of materials, including concrete, asphalt, and cut stone. Figure 6.3 illustrates a variety of commonly used barrier and mountable curbs.