Tool Box
Neighborhood Traffic Management Program

NECKDOWN/BULBOUT

Neckdowns/bulbouts are raised curb extensions that narrow the travel lane at intersections or midblock locations. Neckdowns/bulbouts “pedestrianize” intersections by shortening the crossing distance and decreasing the curb radii, thus reducing turning vehicle speeds. Both of these effects increase pedestrian comfort and safety at the intersection.

The magnitude of reduction in speed is dependant of the spacing of neckdowns between points that require drivers to slow. On average neckdowns achieve a 7% reduction in speeds

Advantages

• Reduces pedestrian crossing distance and exposure to vehicles
• Through and left-turn movements are easily negotiable by large vehicles
• Creates protected on-street parking bays
• Reduces speeds (especially right-turning vehicles) and traffic volumes

Disadvantages

• Effectiveness is limited by the absence of vertical or horizontal deflection
• May slow right-turning emergency vehicles
• Potential loss of on-street parking
• May require bicyclists to briefly merge with vehicular traffic

For additional information please contact:

Tracy Whitley
Project Engineer
Sacramento County Department of Transportation
whitleyt@SacCounty.net