The Ins and Outs of Traffic Calming

Cut-through traffic and speeding issues on local roadways are two of the more common complaints that city engineers and public works employees receive from concerned citizens. Traffic engineers have developed a variety of strategies to help mitigate these issues. These strategies are known as traffic calming.

Per the Federal Highway Administration and Institute of Transportation Engineers: “traffic calming reduces automobile speeds or volumes, mainly through the use of physical measures, to improve the quality of life in both residential and commercial areas and increase the safety and comfort of walking and bicycling.” In addition to reduced traffic speed and volume, other benefits of traffic calming include reducing crash frequency and severity, the need for police enforcement, and cut-through traffic. 

While most people immediately think of “speed bumps” when they want to slow vehicles down, there is a long list of typical traffic calming measures, including:

  1. Vertical Deflections (Speed Humps, Speed Bumps, Speed Tables, Speed Cushions, Raised Crosswalks, and Raised Intersections) 
  2. Horizontal Deflections (Chicanes, Lateral Shifts, Roundabouts, and Traffic Circles)  
  3. Street Width Reductions (Median Islands, Corner Bulb-outs, and Road Diets)
  4. Route Restrictions (Median Barriers, Road Closures, and One-way)

Sain has on-call contracts with cities to help them respond to citizen complaints related to traffic calming. Several cities in Alabama, like Vestavia Hills, have their own traffic calming policies in place that define a process for implementing traffic calming measures if deemed appropriate. A good practice with traffic calming policies is to require that a certain percentage of citizens in the affected neighborhood agree with the need for traffic calming measures. This helps ensure that traffic calming measures are supported by more than just the most vocal citizen on the street.  

Traffic Calming Measures
Raised Crosswalk with Corner Bulb-Outs, by Scott Batson.