Ourston Roundabout Engineering | Design Oversight

By: Roundabouts  09-12-2011
Keywords: Guides, Traffic Control, Modern Roundabouts

When it comes to the use of a new traffic control device, prudent agencies turn to the most qualified in the industry to give them the confidence of long time experience.  We assure agencies of the correct site selection and design quality with the highest degree of skill and professionalism, applying science and deep experience with corporate and personal commitment to our valued clients.

Quality Assurance

Design, the way we've come to experience roundabouts, is holistic.  Signs, markings, geometry, lighting, and landscaping all contribute to structuring driver responses.  Failure in one aspect of design cannot be compensated for by overemphasizing another aspect.  Novice or casual designers of roundabouts overlook composition most of the time at the earliest stages, and then sacrifice the design at the latter stages.

[Knowledge of the Essential Demands of a Good Roundabout Design + Disciplined Proven Design Skills] = Assurance of Quality

When giving oversight to designs prepared by others, Ourston's uses guides, models and principles of modern roundabouts with these axioms:

  • A good design guide is extremely useful but not sufficient by itself.
  • A good computer model is essential but not sufficient by itself.
  • A good designer is most essential but an expert is indispensable.

An expert is the only source of heuristic knowledge – the most important type of knowledge.  The expert uses models and guides wisely.  All three, guides, models and the expert are needed and must be proven with a track record that is tested by time.  We uphold these values by having dozens of built complex roundabouts in dense traffic situations to our credit.  We can provide quality assurance because our own work has performed well for nearly two decades.

Ourston Roundabout Engineering, Inc. has operated in the role of reviewer performing design services indirectly or vicariously through local consultants.  We assure clients that their consultant's work will result in functional, safe and efficient roundabout operations.  We provide troubleshooting advice on preparation of plans and specifications with consideration for the following elements:

  • Check design vehicle turning movements.
  • Review crosswalk locations and ramp treatments.
  • Review and design guidance on vertical design and typical cross-sections.
  • Review signing and suggest need for map-type or other directional sign layouts and locations, lane designation signs, exit signs, route confirmation signs, etc.
  • Review pavement markings including lane designation arrows, crosswalks, entry, and exit markings.
  • Review special marking requirements for exclusive turning lanes.
  • Landscape and lighting design
  • Recommend planting height limits according to visibility requirements.
  • Review lighting design confirming pole location and luminance requirements.
  • Review photometric assessment of lighting levels based on preferred pole locations.
  • Review and provide recommendations on construction staging.

In the delivery of design oversight we contribute heavily to the initial layout effort then guide the prime consultant through the detailed design with oversight of the above design elements. 

Project Mentoring

Ourston also provides mentoring services to agencies wanting to develop their in-house design skills.  This is a priority for us because we believe that a well educated agency will be able to troubleshoot poor designs and advance their roundabout program with fewer pitfalls.  We help them enough to enable them to grow their staff design skills to independence.  To us, the more roundabouts that get built with good functionality the better for everyone.  This is why our former President, Leif Ourston used to say, "Give everything away."  He knew that there are too few that can competently design a roundabout and that would slow the advancement of building safer intersections.

The process of project mentoring involves our experts guiding the hands of the designer through the analysis and composition of functional layouts. The CAD work remains in the hands of the designer, while the mentor guides and educates. The mentor prompts the designer to attend to critical aspects of the project to avoid typical pitfalls. In addition, the mentor guides the project staff through the planning and public acceptance of the project.

Knowledge Transfer

Ourston Roundabout Engineering, Inc. can lead face-to-face knowledge transfers and layout review workshops with the agency staff.  The focus of the workshops is to describe the analysis and revision process for the design.  We lead the workshops covering the following topics:

  • Project background
  • Description of expert roles, responsibilities and deliverables.
  • Description of the review, analysis and evaluation process that took place
  • Summary of expert recommendations.
  • Discussion regarding exceptions to current design practices.
  • Question and answer session.

Construction Reviews

We can provide on-site review of issues or problems arising during the construction phase of a roundabout project.  Several agencies have us visit sites during the milestones of construction (curbs, pre-marking and sign locating) to assure the functionality of the as-constructed conditions.  These are typically sites that have longstanding roundabout programs and have experienced the benefits of catching issues during construction.  Examples of our clients include: Maine DOT, Arizona DOT, Wisconsin DOT and the Colorado DOT.

Keywords: Guides, Modern Roundabouts, Traffic Control,

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This report was prepared for D.O.T. of Wisconsin to evaluate alternative traffic controls for STH 28 from County Trunk Highway ‘A’ to Greenwing Drive. LENTERS, M; WEBER, P. "Synthesis of North American Roundabout Practice", Transportation Association of Canada, 2009. Ourston's research and publication of case studies and technical reports feeds our design practice.


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