Nixon/Green/Dhu Varren Roundabout & Nixon Road Corridor Study

Single-Lane Roundabout Improves Safety and Traffic Flow for Travelers

In order to streamline travel and increase safety for drivers, cyclists and pedestrians, the City of Ann Arbor asked OHM Advisors to complete a roundabout design at the highly-traveled offset “tee” intersections of Nixon, Green and Dhu Varren roads, and to perform a corridor study along the Nixon Road from the north city limit to its intersection with Plymouth Road. Our transportation planning and engineering teams conducted a multimodal analysis, evaluating the needs of motorized vehicles, bicyclists and pedestrians. We performed vehicle analysis based on conventional capacity methodology; traffic analysis with PTV Vissim software; and for our non-motorized analysis, used a method that focused on the quality of the walking and biking experience in the busy intersection area. Prior to designing the solution, our team also helped the City conduct an extensive public engagement campaign with local residents in order to collect their valuable feedback and insights.

With the results, we created a roundabout design aligning the two offset “tee” intersections with a single-lane roundabout to maximize safety and traffic flow in the area. Included in the design were cross sections, alignments, removals, construction sheets, profiles, utilities, construction staging, detailed grading, wetland mitigation, permanent signing, pavement markings, landscape architecture, lighting, soil borings, soil erosion and sedimentation control. Our multidisciplinary team also provided construction engineering assistance and construction staking during the construction phase of the roundabout.

Project Highlights: transportation planning, traffic studies, multimodal analysis, non-motorized pathways, design engineering, roundabout design, survey services, public engagement, construction engineering, landscape architecture