agencies resulting in a total crash reduction of 8 to 14 percent – an injury reduction of 12 percent also can be expected.

The NCHRP Report 731 also recommends using a design speed of 20 MPH for left turning vehicles which is used by the City of Kettering. The left turn crashes therefore are believed to be a function of sight distance and not clearance timing as discussed above.

2. Upgrade existing traffic signal installation: Upgrades to the existing traffic signal are recommended in conjunction with the lane configuration and clearance interval changes and to address the observed need for signal maintenance. The recommendation includes the following components and has potential to mitigate all intersection related (non-driveway) crashes.
  • Replace all signal heads and provide reflective back plates on new heads
  • Add supplemental signal head to the east and westbound approaches to compensate for the horizontal curve on both approaches. Mount a single, 3-section signal head near side, far right to maximize visibility of the signal installation.

Implementation of the following countermeasures are proposed to be incorporated as part of the currently programmed resurfacing project (PID #97897). The design schedule could be accelerated in 2016 to meet a plan sale date of May 2017.

1. Shroyer Road diet. Convert the existing 4-lane section of Shroyer Road north of Dorothy Lane to a 3-lane section with raised medians and bike lanes. Overhead lane use signs are included as part of the lane conversion project. The final decision to convert Shroyer Road to a 3-lane section as part of the roadway resurfacing project is needed by April 2016 to meet a May 2017 sale date.
2. Median reconstruction. Reconstruction of the existing median on Shroyer Road is proposed to be incorporated as part of the currently programmed resurfacing project (PID #97897). 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.

General improvements to the traffic signal installation can be implemented as part of a separate project. Additional design is required to confirm the existing strain poles are adequate to support the increased loading caused by additional signal heads and backplates. The ability of the overall construction budget to accommodate an increase of scope and the associated design time are factors that affect the implementation schedule of signal improvements at Dorothy Lane/Shroyer Road.

Note that improvements to the Shroyer Road corridor should extend beyond the existing curb lines. Construction activities that extend beyond the existing right of way limits should be avoided to meet schedule commitments for the federal funds.

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