Speed Cushion Pilot Project

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Pilot Results We want to hear from you Pilot Completion

The City of Raleigh is evaluating a traffic calming device that is new to the city called a speed cushion.  Speed cushions have the potential benefit of lessening the impact to city and emergency services by allowing vehicles such as fire engines or buses to straddle the speed cushion with little to no impact as they pass over it.  Cyclists will also benefit by having the ability to easily avoid the speed cushion by riding between them.

Speed cushions are designed so that single occupancy vehicles, which are usually the leading cause of neighborhood speeding, are the main mode of transportation impacted since they will not be able to straddle the speed cushions and must drive over them.

The speed cushions that are being placed as part of this project are of a similar size and profile as the current asphalt speed humps used throughout Raleigh.  Treatments that are the size and shape of the speed cushions we being placed have been designed to encourage speed compliant behavior, with the vast majority of cars driving at speeds in the range of 23 mph – 27 mph.  As S State St has a speed limit of 25 mph, this design speed aligns with the speed cushion design specifications.

rubber speed cushions

The speed cushions are made of compressed rubber from recycled materials.  The recycled rubber acts as a noise absorber so when vehicles drive over them, it will lessen the already minimal noise impacts to the surrounding residents.

S. State St was chosen as the pilot project location because it was the highest qualifying street that met all the criteria in Section 10 of the NTMP policy.  Those criteria include:

  • The street must already be eligible for a future traffic calming project
    • Based on the most recent evaluation S. State St had approximately a 7-mph speed compliance issue (32 mph in a 25 mph zone) and there were 3 speed related crashes in the previous 3 years
  • The street length shall be approximately ¼ mile in length or shorter
  • The street must have successfully completed a speed limit reduction from the statutory 35 mph set by the NC General Assembly
  • The street must have curb & gutter on both sides of the street
  • The street must have an average daily volume of approximately 1,200 vehicles per day or less
  • The street cannot be on the Raleigh Fire Department’s priority route list

Pilot Results

The results are in!

The modular speed cushion pilot project has come to an end due to one of the modular speed cushions being damaged, resulting in it needing to be removed.  Over the course of the pilot period, it was found that the modular speed cushions themselves worked as intended, but the durability was not up to our standards.

Below is a summary of the results of the modular speed cushion pilot project:

  • 828 South State Street

            Pre-pilot driver speeds: 31.24 mph in the 25 mph zone

            Pilot driver speeds: 25.59 mph in the 25 mph zone

  • 717 South State Street

            Pre-pilot driver speeds: 32.83 mph in the 25 mph zone

            Pilot driver speeds: 25.19 mph in the 25 mph zone

The modular speed cushions slowed drivers down to the speed limit with an average reduction in driver speed of 20.75% from their pre-pilot driving speeds.

We want to hear from you

Take our survey!

This section of South State Street was chosen because it was identified as a street with a speed compliance issue.  As you can see from the results, the modular speed cushions had a positive impact on driver speeds.

With the pilot period ending, we want to hear from you and your experience surrounding having traffic calming on your street.  Please take our survey and share your thoughts and experiences while the modular speed cushions were in place.


This open comment period will end on September 18, 2021.

Pilot Completion

Next steps

Once the open comment period comes closes, the modular speed cushion pilot project will come to an end and the remaining modular speed cushions will be removed.  The neighborhood will have an opportunity to vote whether or not you would like to have permanent asphalt speed humps placed in the same location as the modular speed cushions are currently located.

The asphalt speed humps would be placed at the property line between the addresses:

  • 719 & 721 South State Street
  • 827 & 833 South State Street

The ballot will be sent to all properties that abut South State Street after the open comment period closes. A minimum approval rating of 50% + 1 from the responding residents will be needed for the pilot to become permanent.

Thank you for working with us as we continue to evaluate new and innovative ways to improve speed compliance along Raleigh’s neighborhood streets.  We look forward to hearing from you!

asphalt speed cushion



Will Shumaker
Traffic Calming Administrator

Service Categories:
Traffic Engineering