When concerns about speeding on a residential street and a request for the installation of speed humps are received, County staff will conduct a traffic study at the site. The traffic counter, with two tubes placed on the road, will collect speed, volume, and direction data. The results of this study will indicate the severity of speeding on the street. 

Depending upon the results of the speed study, a speed hump layout may be prepared and then sent with a petition to the citizen making the request. A percentage of the property owners along the affected street will have to approve the layout on a formal petition before the proposal is forwarded to the Board of Commissioners for approval. The petition process allows the neighborhood to make the decision if speed humps are the appropriate tool for them.

The speed hump installation costs are paid from the Special Purpose Local Option Sales Tax program, known as SPLOST. Annualized assessments based on the costs associated with maintenance and repair of speed humps are added to the property tax bills at the end of the year. Each platted lot, whether developed or not, will be subject to the assessed charges. The rate for participation in the Speed Hump Program will be assessed annually per property in the defined service area.

Speed humps are not used to slow traffic at a given point, but rather to reinforce a safe speed along a street or street section. In most applications, they are spaced between 300 – 500 feet apart since studies in Gwinnett and across the nation indicate that this is the most effective method to reduce the 85^th percentile speed to between 25 and 30 mph. 

The first hump in a series is located near a controlled intersection to deter a motorist approaching a speed control district at excessive speeds. Speed humps are not located on hills with a grade greater than eight percent.

Stop signs are used to assign right-of-way at busy intersections. National standards have been established to determine when stop signs are warranted, taking into consideration traffic volume, sight distance, and accident history. Engineering studies across the nation have shown that multi-way stops do not work well as speed control devices. While speeds decrease in the immediate vicinity of unwarranted stop signs, speeds often increase between stop signs as drivers “make up for lost time,” thus any effect that they have on speeds is purely local. 

Stop signs also increase air pollution, waste fuel, and create more traffic noise. Most drivers are reasonable and prudent. When confronted with unreasonable and unnecessary restrictions, motorists are more likely to violate them, which often leads to contempt for other traffic signs. For this reason, the Gwinnett Department of Transportation does not recommend multi-way stop signs for speed control.

Gwinnett uses a neighborhood-driven approach to residential speed control. For the speed humps to be effective, the installation should be supported by the property owners along the subject street. The County staff is responsible for managing the Speed Hump Program, while the property owners are responsible for obtaining community support. 

The petition should be circulated in the neighborhood by the requesting citizen or other community representative. Each property owner listed on the deed/title — including a spouse or if the deed lists “et al” — is required to sign the petition. When a property owner offers to sign the petition, it is an indication that he or she understands the speed hump proposal and the related information. A witness is required to verify each signature.

The petition coversheet, which should be read by all affected property owners, outlines the aspects of the Speed Hump Program. The property owners of the affected street, or defined service area, will become a part of a special assessment district of properties that will directly benefit from the speed hump installation. 

Once approved by the Board of Commissioners, this special assessment district will be charged the annual maintenance fee on their property tax bill. Residents on other streets will not be affected since they will not be within the special assessment district and thus are not eligible to sign the petition.

Gwinnett uses devices called speed humps, which are designed to achieve a specific result on vehicle operations without imposing an unacceptable or unreasonable safety risk. Motorists can travel along the street at speeds close to the posted speed limit with little or no discomfort. Speed bumps, on the other hand, are abrupt devices designed to be crossed at slow speeds and are mostly used in parking lots or private driveways.