Traffic Engineering

Traffic Calming


The purpose of this Section to provide policies and procedures for installation and design of traffic calming devices within unincorporated Seminole County.  On October 27, 2020, the Board approved the use of the following traffic calming devices on County roadways to reduce vehicle speeds:

  1. Speed Cushions / Speed Humps
  2. Speed Display Trailers / Post Mounted Electronic or Solar Radar Speed Signs
  3. Mid-Block Chokers
  4. Chicanes
  5. Traffic Circles
  6. Roundabouts
  7. Median/Center Islands
  8. Gateway/Entry Features

Speed cushions were discussed as part of Board meetings and worksessions in March 2018, February 2020 and August 2020.  Further details on speed cushions are given below.  Traffic Calming Devices #2 through #8 above are detailed in Section 4 of the County’s Traffic Calming Program manual dated July 2005.

Traffic calming devices will be approved by the County based on the latest Traffic Calming Criteria (see below).  As identified in the criteria, the roadway must have a documented issue with speeding.


Below is the current criteria for determining if traffic calming devices are warranted:

  1. Roadway must have a documented issue with speeding (observed 85th %-tile speed is greater than 10 mph over posted speed limit)
  2. Minimum/Maximum Roadway Volume: 750 vehicles per day / 5,000 vehicles per day (to be determined through existing annual counts, if available, or a new count)
  3. Maximum Speed:  The posted speed on the roadway must not exceed 30 mph
  4. Homeowner approval for installation (and removal):  65%
  5. Consider other owners impacted by devices (side streets) on a case by case basis 
  6. Functional spacing of devices (primarily for speed cushions or humps) :
    1. 300’-400’ between devices
    2. Not on curves/turns
    3. Minimum of 100’ from intersections or curves/turns
    4. Spacing subject to adjustment for driveways
  7. Roadway must have driveways that directly access the road.
  8. Roadway must be subject to through traffic - not in a “closed development”.
  9. Roadway must not be a principal arterial, minor arterial or major collector roadway – must be a local street or minor collector (evaluated on a case by case basis)
  10. Roadway character/location (rural vs. urban) – considered on a case by case basis

Nothing above shall limit the County Traffic Engineer’s or County Engineer’s ability to install any devices upon the County roadway system that in their sole opinion is justified for the maximum safety of the motorists or residents and does not impede Public Safety operations.

The above criteria was recently developed for speed cushions. This criteria could also apply to some devices from Section 4 of the 2005 Traffic Calming Program manual, such as mid-block chokers, chicanes and median/center islands. Other devices in the manual, such as speed display trailers/post mounted electronic or solar radar speed signs, roundabouts, traffic circles and gateway/entry features, would have different criteria to be determined by the County Traffic Engineer or County Engineer if those devices were desired.


The Board recognizes there is no dedicated funding for any traffic calming devices at this time.  The Board may decide to dedicate funding in the future through a budgeted program or through individual projects.  In the absence of County funding or assistance, communities may receive County approval to design and install traffic calming devices through the County’s Municipal Service Benefit Unit (MSBU) program.

What is an MSBU? An “MSBU” (Municipal Service Benefit Unit) is a non-ad valorem assessment district created to fund a public service or capital improvement. An MSBU consists of a group of properties that share in the benefit and cost of the service provided. The assessment allocated to each property is based on the service cost, total number of benefit units and the number of benefit units assigned to each property. A benefit unit may be a parcel, dwelling, linear foot or other equitable unit.  In short, you and your affected neighbors will pay an amount annually for a determined number of years to fund the traffic calming measures desired for your roadway.  More information on the MSBU program

The cost for speed cushions varies depending on the material.  Pre-fab rubber cushions that were used at the County’s four (4) pilot project locations were $6,200 per location.  This was for a set of two (2) that were good for a roadway width of 24’ or less.  Assuming 300’-400’ spacing between locations, rubber cushions are roughly $93,000 per mile.  Asphalt cushions are significantly less expensive at about $4,000 per location or $60,000 per mile.  The other traffic calming device options, #2 through #8 above, are significantly more expensive, current estimated costs.     


Below is the process for an organization or group (neighborhood, community, HOA, etc.) to request a review for potential traffic calming devices on a County maintained roadway funded through the MSBU program:

The requested roadway must meet the criteria noted below to qualify for traffic calming consideration:

  1. Roadway must be subject to through traffic - not in a “closed development”.
  2. Roadway must have driveways that directly access the road.
  3. Maximum posted speed limit 30 MPH

If the roadway meets the noted criteria, Traffic Engineering staff will do a preliminary review.  If the roadway itself meets criteria, a speed and volume study will be scheduled.  If the speed studies indicate that there is an issue with excessive speeds (observed 85th %-tile speed is greater than 10 mph over posted speed limit) AND traffic volumes are above 750 vehicles but below 5,000 vehicles per day, we will contact the organization or group and ask for a formal request with a pre-application survey of interest. 

This survey of interest will include signatures of at least 35% of the households along the affected roadway indicating they wish to pursue traffic calming further.  The intent here is to verify the request is supported by a significant number of concerned citizens; not just one.  There will be no fee at this time. Staff will then review the formal request, verify again the roadway meets the criteria and draft a solution and cost. 

If the applicant still wishes to move forward with Staff’s proposed solution, we would have them formally apply for an MSBU through the County’s MSBU Program.  At this point there will be an application fee.  In order for the MSBU to be approved, 65% of the affected property owners must approve the plan. 

Seminole County Traffic Calming Request Form


Speed cushions are to be designed to allow emergency vehicles unimpeded travel through the devices. The following design considerations are to be used and any cushions installed on County roadways shall be approved by the County Engineer or County Traffic Engineer. Cushions may be fabricated from pre-fabricated rubber pieces, similar to Traffic Logix Speed Cushions or equal, or in-place constructed asphalt sections. Cushions shall be made up of two (2) or three (3) sections for each location along the roadway. The width of the sections shall be six feet (6’) and they shall be installed with a minimum two foot (2’) gap between sections. The length of the sections shall be twelve feet (12’) or longer to set the desired speed over the cushion. The general design of cushions will be subject to approval by the County Traffic Engineer or County Engineer.  The City of Orlando’s Speed Cushion design, was used as a template.   


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