Details
Type: Bulletin
Topic or Program: Access Management | Left Turn Conflicts
Final Number: AM13-04(B)
Effective Date: 05/01/2013
Updated Date: 03/18/2015
Signature on File: Larry McKinley, Access Management Program Manager
Purpose
This Technical Services Bulletin provides guidance for understanding and applying OAR 734-051-4020(3)(b) regarding left turn conflicts. Left turn conflicts from offset connections located on the opposite side of the highway may result in overlapping left turn movements or competing use of a center turn lane that cause a safety or operations concern that may impact the decision to approve or deny an approach application or existing connection. This guidance will help to achieve greater statewide consistency in the evaluation process and to increase understanding of the factors that need to be considered in resolving problems related to offset connections.
Definitions
See Attachment A. OAR 734-051-1070 also contains definitions applicable to this bulletin.
Guidance
The evaluation process consists of the following four steps:
- Determine if a conflict may exist.
- Determine offset connection desirable spacing.
- Determine if offset connection spacing meets desirable spacing.
- Determine if offset connection(s) that does not meet desirable spacing is a concern.
See Attachment A for interpretations, applications and explanations of each step of the evaluation process. See
Attachment B for background on dimensions shown in Tables 1-4 in
Attachment A.
Background/Reference
In earlier versions of OAR 734-051, safety factors for highway approaches were generally described as:
- Roadway Character
- Traffic Character
- Geometric Character
- Environmental Character
- Operational Character
The previous OAR 734-051 did not quantify or set standards for these safety factors. This was problematic for customers who had no way of knowing how ODOT would make its determination. Senate Bill (SB) 264, which became law in June 2011, amended ORS 374 to establish six explicit criteria for safety and operations criteria that ODOT can consider in its permitting decisions. This bulletin covers one of those set forth in OAR 734-051-4020(3)(b):
(3) Safety and Operations Concerns. The department has the burden of proving safety and highway operations concerns that it relies upon in requiring mitigation or in denying an application based on those concerns. The department may deny an application where the applicant is unable to provide adequate improvements to mitigate documented safety or highway operations concerns; safety and highway operations concerns that the department may consider are limited to (a) through (f), below:
(b) Overlapping left turn movements or competing use of a center turn lane from a connection located on the opposite side of the highway;
Responsibilities
Department staff members in the following positions are responsible for carrying out the guidance in this Bulletin as it relates to their assigned duties and authority:
- Region Managers.
- District Managers.
- Region Access Management Engineers.
- Development Review Coordinators.
- Access Management Coordinators.
- Permit Specialists.
Action Required
- Implement this Bulletin upon the effective date.
Special Instructions
If problems are developed in implementing this guidance or further clarification is needed, contact the Access Management Program Manager.
Attachments