Abstract
Many intersection project sites in North Carolina, and probably across the U.S., have asymmetric conditions. There is typically heavier demand from one approach than the others, right of way is more restricted in one or two quadrants than in the others, pedestrian demand is concentrated in one crosswalk, and so forth. However, the literature on alternative intersections and the software that planners and engineers use to explore suitable alternatives primarily provide symmetric and full designs. Analysts reading the FHWA guidebooks on alternative designs or looking at the menus of CAP-X or VJUST would be led to believe that their options were limited. Fortunately, in the past few years it has become apparent that there are many more intersection design options than presented in CAP-X or VJUST. The objective of this paper is to demonstrate that designers can combine pieces of the alternatives in many creative ways to find asymmetric designs that better fit whatever asymmetric conditions they are given. This paper shows some hybrid at-grade and grade-separated intersection designs that seem to have potential to increase efficiency, increase the quality of the pedestrian and bicyclist crossing experience, decrease impacts, and have other benefits. Based on these examples, it should be apparent that many interesting combinations are possible. Designers wanting to explore a hybrid cannot use the usual software to do so, but the tools to analyze a hybrid design are available if one knows where to look.
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