There were a total of 9 left turn crashes occurred on the Shroyer Road approaches to Dorothy Lane:

• Five (5) left turn crashes involving southbound left turning vehicles and northbound through vehicles. One northbound through motorist was at-fault for a red light running violation.
• Four (4) left turn crashes involving northbound left turning vehicles and southbound through vehicles. Two southbound through motorists were at-fault for red light running violations.

Raised medians extend to the stop line adjacent to the southbound left turn lane to control access to private driveways within the functional area of the intersection. The raised medians, however, reduce the available sight distance of left turning vehicles during the permissive left turn phase.

Similar to the eastbound left turn movement, sight distance of 150 feet or less is available when an opposing northbound left turn vehicle is present. The ODOT Location and Design manual, Volume 2, Figure 201-1E suggests a minimum stopping sight distance of 250 feet for speeds of 35 miles per hour. The available sight distance is not adequate for approach speeds greater than or equal to 25 miles per hour.

Two low cost countermeasures are proposed to mitigate left turn crashes on the Shroyer Road approaches:

• Reduce length of median on the southbound Shroyer Road approach by 25 feet. Add painted island between the through and left turn lanes to encourage drivers to favor the painted centerline thus improve intersection sight distance.
• Add a painted island on the northbound approach between the through and left turn lanes. The painted island is to encourage drivers to favor the painted centerline thus improve intersection sight distance.

Implementation costs if incorporated as part of the resurfacing project is estimated at $5,000 for sawcut of pavement, excavation, pavement markings, and concrete median costs. Maintenance of traffic is included as part of the separate resurfacing project.

The following countermeasures are recommended to mitigate crash frequency at the Dorothy Lane and Shroyer Road intersection:

1. Review clearance Intervals. A review of the yellow change and all red clearance times for through movements is recommended. The standard yellow clearance for a 35 MPH is 3.6 seconds whereas yellow clearance times of 3.9 seconds (40 MPH) for the Shroyer Road approaches and 4.2 seconds (45 MPH) for the Dorothy Lane approaches are currently programmed. NCHRP Report 731 dated July 2012 confirms that the ITE clearance interval guidelines are used by the highest percentage of state and local