road diet on Oberlin Rd

Road Diets: The Science Behind Safer Streets

Road diets help you navigate traffic easier and safer.


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What is a road diet? The science behind road diets Why install road diets? Recent road diet projects

What is a road diet?

  • A road diet is a conversion of usually a four-lane roadway to a three-lane road made up of two through lanes and a center-two-way-left-turn -lane. Drivers can use the dedicated turn lane to safely turn and move out of the traffic flow, so they're not holding up drivers behind them. 
  • With a road diet, left turns will only cross one lane of traffic instead of two. The reduction of lanes allows the roadway cross section to be reallocated for other uses such as bike lanes, pedestrian refuge islands, transit stops, or parking. 

The science behind road diets


Studies conducted by the Federal Highway Administration have found several benefits of road diet installation: 

 

• An overall crash reduction of 19 to 47 percent. 

• Reduction of rear-end and left-turn crashes through the use of a dedicated left-turn lane. 

• Fewer lanes for pedestrians to cross and an opportunity to install pedestrian refuge islands. 

• The opportunity to install bicycle lanes when the cross-section width is reallocated.  

Why install road diets?

  • Reduces traffic speed
  • Reduces rear end and head on collision crashes
  • Accommodates bike and enhanced pedestrian safety
  • Creates better connectivity for pedestrians and bicyclists
  • Dedicated turn lanes ease anxiety for drivers

Recent road diet projects


Lake Boone Trail Safety Improvement Project

We are enhancing Lake Boone Trail between Ridge Road and the I-440 ramps. A major component of this project is lane reconfiguration. Lake Boone Trail is currently a four-lane road. This type of lane configuration tends to have more crashes because of conflicts with turning traffic. 

We are converting the road (from Ridge Road to I-440 ramps) to a three-lane roadway with a center turn lane. The conversion decreases points of conflict between vehicles and prevents drivers from blocking travel lanes. 

The road diet allows us to add bike lanes along the corridor and a pedestrian refuge island allowing safer connectivity to transit and the greenway trail along the street. Adding these components provide safety measures for both bicyclists and pedestrians.

Road diets help make Raleigh streets safer, and safe streets are Complete Streets.

Contact

 

Transportation Department Assistant Director 
Kenneth Ritchie
Kenneth.Ritchie@raleighnc.gov

Roadway Design and Construction Division Manager
Sylvester Percival, PE
Sylvester.Percival@raleighnc.gov

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Lead Department:
Engineering Services
Service Categories:
Roadway Design and Construction