Reconstructing a Six-Leg Intersection into Mohave County’s First Roundabout

: Mohave County, Arizona maintains a six-leg intersection in the Golden Shores area bisected by an uncontrolled regional County highway, County Route 1, where two STOP-controlled section line local roads converge. The two-lane, rural CR 1 serves commuter and visitor traffic traveling between population centers of Lake Havasu City, AZ and Bullhead City, AZ/Laughlin, NV on the Colorado River and its desert lakes. The intersection features 180 total vehicle-to-vehicle conflict points inclusive of 126 crossing conflicts. This paper presents the County’s technical and administrative approach and techniques in planning and developing the CR 1 “Six Points” roundabout given the (1) absence of fatal and incapacitating injury crash history and (2) backdrop of this improvement representing the County’s first roundabout. Project initiation entailed the County securing a Federal share of Highway Safety Improvement Program funding at 100-percent. Project design commenced with a preliminary engineering study to identify, evaluate, and solicit public input on alternative improvement solutions as part of validating the roundabout improvement as superior for traffic operations, community and business function, sitting, and constructability. Public input targeted preference for maintaining CR 1 uninterrupted flow versus interrupted flow introduced under roundabout circulation. This simple decision tree enabled the County to understand existing operational and access conditions important to the public, business owners, and public safety providers for purpose of configuring a roundabout improvement satisfying local motorist and community needs, which stoked stakeholder buy-in on the project.