Roadway reconfiguration - "road diet"

Safety issue

In areas with a high number of access points, there can be numerous crashes due to turning vehicles. Conflicts with pedestrians and bicyclists are also a concern in areas with a high number of access points and turning vehicles.

Roadway before      
Roadway after

Safety design

A common roadway reconfiguration or "road diet" consists of converting a four-lane roadway (two lanes in each direction) to a three-lane roadway (one lane in each direction plus a center left-turn lane) and adding sidewalks and/or bicycle lanes.

Road diets reduce the number of vehicle conflicts which has been shown to decrease the number and severity of crashes. Road diets also improve safety for non-motorized traffic by providing designated spaces -- sidewalks and bicycle lanes -- that reduce conflicts between motor vehicles and other road users.


  • Decreases vehicle travel lanes for pedestrians to cross, therefore reducing pedestrians exposure to vehicular traffic
  • Provides space for pedestrian crossing islands
  • Improves safety for bicyclists when bike lanes are added
  • Reduces rear-end and sideswipe crashes

Where are they being used?

  • Road diets are happening on urban four-lane roadways with moderate traffic volumes and a higher proportion of turning traffic due to adjacent access.
  • Road diets can be completed as part of routine repaving projects.​


Dan Brugman, P.E., RSP1
WisDOT State Safety Traffic Engineer
(715) 421-8337