3C-2: Curbs

General Curb Design Information

The Department recognizes three curb designs:

1. 6-inch standard curbs.

2. 4-inch sloped curbs.

3. 6-inch sloped curbs.

Details of these curb designs can be found in PV-102 or the 6000 series of Road Design Details. 

The use of other curb designs is discouraged, but may be necessary where site conditions dictate.  For projects at spot locations, it is acceptable to use a curb design that perpetuates the design that is predominant in the adjacent roadway sections.

A design speed greater than 45 mph is considered “high-speed” when designing curbs.  If possible, curbs should not be used in high-speed locations.

Guardrail alongside curbs should be avoided.  Instead of using guardrail, every effort should be made to remove fixed objects or relocate them outside the clear zone.  If there is no other alternative to using guardrail, refer to Section 8C-2 for guidance on placing guardrail alongside curbs.

Curbs for stop sign islands should match the design of the curb used on the mainline.  For rural roadways, use a 4-inch sloped curb.

Curb Placement

The location of the face of curb in relation to the edge of traveled way may affect the lateral placement of a moving vehicle because drivers tend to shy away from curbs.  Table 1 provides guidance for locating curbs.

Curb Transitions

Sloped curbs are wider than the 6 inch standard curb.  When transitioning from sloped curb to standard curb or from standard curb to sloped curb, maintain the back of curb and transition the gutter line as shown in Figure 1.

Figure 1: Standard to sloped curb transition.

Chronology of Changes