WSDOT ROUNDABOUT SCOPING ASSESSMENTS – Skagit and Whatcom Counties, WA (2004 -2007)
Reference: Washington State Department of Transportation, Gus Deeter: 360-428-1593
While employed at the WSDOT, John Tuttle prepared numerous scoping packages and detailed assessments of all key capital facilities required to convert conventional intersections to roundabouts. The primary function of these studies was to compare the net benefits of a roundabout (reduce crashes, separate vehicle and pedestrian conflicts, increase corridor safety and circulation, reduce fuel consumption) to those of a typical traffic signal. A phased methodology was created for the planning of specific intersections improvements that would ultimately serve much larger portions of Skagit and Whatcom Counties for which they would serve. Completed studies were then passed through a strengths and weaknesses process to identify a strategic and methodical use of limited federal funding and to program specific projects for design. Preliminary design followed with assessments of fastest path, off-tracking, and 3-D geometrics using Torus and AutoTurn software. Final P,S&E utilized findings of preliminary design to prepare included preparation of contract plans, estimates, and detailed contract specifications developed using the complex WSDOT Spec Compiler program.