Traffic Calming Frequently Asked Questions

What is the purpose of traffic calming?

Traffic calming is intended to improve safety and quality of life on neighborhood streets by reducing excessive vehicle speeds, crashes, and discouraging unsafe driving behaviors. Traffic calming measures help create streets that are safer and more comfortable for people walking, bicycling, driving, and accessing their homes.

How will my feedback be used?

Community feedback helps City staff understand neighborhood preferences, identify concerns, and refine project recommendations. All comments received during the project development process are reviewed and considered as part of the final design.

How does this afffect emergency response?

• Speed Humps: Average 2-5 second delay per treatment location
• Speed Cushions: Average 0-2 second delay per treatment location
• Speed Tables: Average 2-5 second delay per treatment location
• Horizontal Treatments (ex. Traffic Circle): Average 1-3 second delay per treatment location

What is the difference between a Speed Hump, Speed Cushion, and Speed Table?

• Speed Humps are a vertical traffic calming treatment that crosses the full width of a street and are intended for streets with a 25 mph speed limit.  They are 12’ long and 3” tall.
• Speed Cushions are a vertical traffic calming treatment that have gaps in the hump that are intended for streets with a 25 mph speed limit.  The gaps in the hump allow for emergency services vehicles with wider wheel basis to straddle the humps to minimize the impact to their response times but are still large enough to impact normal vehicles.  This style of treatment is the preferred treatment style for streets designated as a Neighborhood Bikeway.  They are 12’ long and 3” tall.
• Speed Tables are a vertical traffic calming treatment that crosses the full width of a street and are intended for streets with a 30 mph speed limit.  They are 22’ long and 3” tall.

What are the core goals of this project?

Traffic calming projects have a goal of addressing document speed compliance issues and/or eliminating identified crash patterns.  All projects work to stay completely between the existing curb lines.  Requests such as sidewalk requests or signal installation are not currently within the scope of any traffic calming project.

If these are options you would like to pursue, please feel free to reach out to us at ntmp@raleighnc.gov and we will be happy to direct you towards the proper program/department.

Why are vertical traffic calming treatments typically preferred?

Vertical traffic calming treatments, such as speed humps, speed cushions, and speed tables are generally the most effective tools for reducing vehicle speeds on residential streets. Unlike signs, pavement markings, or other measures that rely on driver compliance, vertical treatments create a physical change in the roadway that encourages motorists to travel at safer speeds. 

Horizontal treatments typically remove parking from both sides of the street in locations where they are implemented, excluding neighborhood traffic circles. They also require less right-of-way, are typically less expensive to construct and maintain than larger roadway modifications, and have a long track record of success in improving neighborhood safety.

Why aren't stop signs being considered?

Stop signs are intended to assign right-of-way at intersections, not control vehicle speeds between intersections. Studies have shown that drivers often accelerate quickly after stopping, which can limit the effectiveness of stop signs as a speed management tool and create a stop compliance issue that places pedestrians at risk. For this reason, traffic calming projects focus on measures specifically designed to reduce speeds along a corridor.

Why aren't police enforcement or speed cameras being used instead?

Enforcement can be effective when present, but it requires ongoing staffing and resources. Traffic calming measures provide a continuous, self-enforcing solution that operates 24 hours a day without requiring routine enforcement activities.