(TWLTL). The reduction of lanes allows the roadway cross section to be reallocated for other uses such as bike lanes and pedestrian refuge islands.

Four (4) lane, undivided roadways such as Shroyer Road experience a number of typical crash types:

  • Rear end and sideswipe crashes caused by speed differential between vehicles;
  • Sideswipe crashes caused by frequent lane changing between two through lanes;
  • Rear end crashes caused by left-turning vehicles stopped in the inside travel lane;
  • Left turn crashes caused by restricted sight distance obstructed by opposing left turn vehicles that are offset;
  • Angle crashes caused by side street traffic crossing four lanes to make a through movement across an intersection, or turning left across two lanes;
  • Bicycle crashes due to a lack of available space for bicyclists to ride comfortably; and
  • Pedestrian crashes due to the number of lanes for pedestrians to cross with no refuge.

An average crash reduction of 30 percent can be expected for all crash types and severity when converting a 4-lane section to a 3-lane section of a minor arterial roadway such as Shroyer Road. A reduction in crashes involving drivers under 35 years of age and over 65 years of age has also been documented with a road diet. Crashes involving at least one driver under 35 years old or greater than 65 years old comprised 73 percent of all crashes on Shroyer Road. A typical section of the road diet countermeasure is shown below with raised medians.

Typical section diagram of road diet countermeasure showing lanes, bike lanes, medians, and sidewalks with dimensional callouts

Implementation of the road diet improvement is proposed to be incorporated as part of a currently programmed resurfacing project. The design schedule could be accelerated in 2016 to meet a plan sale date of May 2017. Reconstruction of the existing median on Shroyer Road near Dorothy Lane is also proposed to be incorporated as part of the currently programmed resurfacing project to mitigate 23 left turn and angle crashes. Median reconstruction includes a median extension to restrict left turn movements from the Speedway site and a median removal to improve intersection sight distance on the Shroyer Road approaches at Dorothy Lane.

Another countermeasure that mitigates an additional 11 left turn crashes at the Dorothy Lane and Shroyer Road intersection includes a protected only left turn phase for the eastbound approach.

2