DES-02: Roundabouts on State Highway System

Type: Directive

Topic or Program: Roundabouts

Final Number: DES-02

Effective Date: 08/22/2017

Signature on File: Paul Mather

Planning for projects and improvements on the state highway system, including intersection control projects such as traffic signal installation or construction of a roundabout involves extensive public outreach, involvement and participation by the wide range of Stakeholders.

This Directive establishes the expectation and processes concerning freight mobility to be followed whenever a roundabout is proposed to be installed on the state highway system.

ODOT’s Mission is to provide a safe, efficient transportation system that supports economic opportunity and livable communities for Oregonians. ODOT remains committed to make the highway system safe and usable for the wide range of users including pedestrians, bicycles, passenger vehicles and large freight trucks; and involves these highway stakeholders in decisions about improvements affecting the highway system.

National data shows that roundabouts improve safety at intersections; reducing fatalities, injuries, and crashes by reducing conflict points and lowering vehicle speeds. In addition, roundabouts reduce intersection delay which reduces emissions.

However, if large freight vehicles are not properly addressed in the roundabout design process, a roundabout can become an impediment to freight movement on the highway. Between May 2011 and the adoption of this directive, ODOT deferred any consideration of the use of roundabouts on the state highway system until the trucking industry’s concerns about roundabouts could be evaluated and assessed. While ODOT is committed to consider the concerns of all highway stakeholders, this Directive addresses the trucking industry’s concerns and requires that those concerns are addressed prior to construction of a roundabout on the state highway system.

When considering a roundabout on the state highway system, follow ODOT procedures that consider the needs and concerns of all stakeholders, including assuring that the roundabout can accommodate the freight movement on the highway. Determining if the roundabout can accommodate freight movement requires conversations with the trucking industry, through the ODOT Motor Carrier Division. Regardless of when roundabouts are being considered; during planning, during project development, or during development review, conversation with the trucking industry is required.

ODOT will address the trucking industry’s concerns in three ways:

1. This Directive and the edits made to the individual ODOT manuals and guidelines listed below make clear that roundabouts proposed to be located on the state highway system shall be designed so as not to impede the freight on the highway, including an evaluation of how over-dimension vehicles will be accommodated.
2. Roundabout-specific communication with the trucking industry is necessary on a case by case basis on decision elements such as route mobility, design vehicle exceptions, over-dimension vehicle to be accommodated, and typical design elements for any proposed roundabout on the state highway system.
3. Prior to construction of a roundabout on the state highway system, a documented agreement will be memorialized with the designated statewide representatives of the trucking industry that the roundabout is properly sized. Properly sized means there is agreement on the selection of the design vehicle to use in design process as provided in the Highway Design Manual chapter on Roundabouts, and that over-dimension vehicles can be appropriately accommodated.

Typical times when roundabouts may be discussed or proposed are during planning activities involving community level and facility level planning, during project development for highway improvement projects and during development review of private developments that impact the state highway system.

The following manuals and guidelines have been or will be edited to address design related issues to assure freight movement is accommodated, as well as to address how to consider roundabouts for planning, project development and design, and development review.

• Highway Design Manual
• Traffic Manual
• Transportation System Planning Guidelines
• Interchange Area Management Plan Guidelines
• Project Delivery Guidelines
• Project Leader’s Checklist
• Analysis and Procedures Manual
• Development Review Guidelines

Following the Direction given above and using the guidance provided in these manuals and guidelines provides good communication with the trucking industry that will result in appropriate decisions about where roundabouts can be placed on state highways, the appropriate design vehicle to be used, the appropriate designs for accommodating freight movement, and how over-dimension freight vehicles can be accommodated.