Unconventional Arterial Intersection Designs Initiatives

This paper addresses initiative works done in the state of Maryland in order to provide a clearing house for unconventional arterial intersection designs (UAIDs) and apply their concepts to selected locations. As a collaborative research effort among the University of Maryland at College Park, Maryland State Highway Administration (MSHA), and Parsons Brinckerhoff Inc., a knowledge base web interface has been built to help traffic engineers, community planners, and elected officials to consider the UAID as a feasible solution for relieving arterial congestion and to select appropriate unconventional design schemes given actual traffic patterns. A great number of statistics on visits and page views show the beneficial effect of the website. The MSHA has also been active in adopting unconventional design concepts at local intersections that incurred operational or safety problems. This paper summarizes four case studies that have been conducted for those locations and treated relatively new UAID concepts, including: 1) superstreet intersection, 2) continuous flow intersection, 3) center turn overpass, and 4) roundabout at high speed approaches. Results of these case studies indicate that the unconventional intersection designs have promise of enhancing not only operational efficiency but also safety along the arterial.