Roundabout Constructability: Considerations and Strategies

A roundabout is a great option for addressing operational and safety issues at intersections. Studies by the Federal Highway Administration and the Insurance Institute for Highway Safety show that replacing a signalized intersection with a roundabout reduces fatality collisions by 90% on average, contributes to an 89% reduction in delays, and reduces vehicle stops by 56%. But how do you handle logistics and keep traffic flowing while building an intersection with a much different footprint?

This two-hour workshop will focus on:

• Construction strategies, including considering project context, applying construction sequence principles, and understanding key considerations

• Construction scenarios such as full closure, partial closure, and staged construction

• Rebuilding a diamond interchange (converting ramp terminals to roundabouts), including design approach, contracting, unique temporary traffic control

• Addressing constructability during planning and design

The presentation will share several project case studies and allow ample time for a discussion of lessons among the presenters and the audience.

7:30AM to 8:00AM – Check-in and Continental Buffet Breakfast
8:00AM to 9:30AM – Presentation
9:30AM to 10:00AM – Questions & Answers

Participants will earn a total of 2.0 professional development hours (PDH) for attending this workshop.

The event will be held at the Hilton Hotel, located at 921 SW 6th Ave, Broadway Conference Rooms III & IV. There is no cost to attend, but seats will be limited. Please RSVP if you plan on attending. For any questions, please contact Norma Jensen at or (503) 535-7451.

We look forward to seeing you there!


Hermanus Steyn, PE, PrEng, Senior Principal Engineer
Kittelson & Associates, Inc.

Hermanus has prepared or peer-reviewed feasibility studies, design plans, and post-construction reviews for over 100 roundabouts throughout the US (more than 10 states). He has served as engineer-in-responsible-charge of developing construction plans, specifications, and cost estimates for the roadway and traffic design elements for several roundabouts, including the first multilane roundabout in Bend, Oregon. For the Federal Highway Administration (FHW) TOPR #34, Accelerating Roundabout Implementation in the US, he led the safety task and supported the trucks/freight considerations task. In addition, Hermanus is the chair of the Transportation Research Board (TRB) Geometric Design Committee. The following is a representative list of cities with roundabout Hermanus worked on:
• Single-lane Roundabouts: Anchorage AK; Nevada City CA; Poway CA; Santa Barbra CA; Lewiston ID; Meridian ID; Albany OR; Astoria OR; Bend OR; Keizer OR; Klamath Falls OR; Medford OR; Oregon City OR; Prineville OR; Sisters OR; Vancouver WA
•Multilane Roundabouts: Fairbanks AK; Pima County AZ; Nevada City CA; San Luis Obispo CA, Maryland; Bend OR; Polk County OR; Warrenton OR; Fort Worth TX; Farmington UT; La Center WA

Darren Hippenstiel, PE, Associate Engineer
Kittelson & Associates, Inc.

Darren is a roadway and project manager with 15 years of experience on developing design and providing support during construction for transportation projects of varying size and complexity. His project experience include design for retrofitting to existing roadways and highways, interchange design, and intersection improvements including more than a half-dozen roundabouts. He has modeled roundabouts for feasibility review through detailing for final plans/specifications and ultimately construction, both on and off-alignment configuration. As a project manager Darren has successfully led multidisciplinary teams on urban retrofit roadway projects, highway interchange designs, rail crossing upgrades, utility undergrounding, pavement rehabilitation, site civil grading and design, trails, and conceptual design and estimating.

In addition to project related activities Darren is an active member of the American Society of Civil Engineers currently serving as a region governor and on national level committees. He is also an active member of the American Public Works Association serving as vice-chair of the transportation committee.

Event Materials