Geometric design parameters

The design parameters are not restrained by any requirement here. They are only constrained by the physical space available to the designer and the configuration selected. The raindrop form can be useful if grades are a design issue since they remove a potential cross-slope constraint on the missing circulatory road segments.

If there are more roads intersecting with the interchange than the single cross road, then two independent circular roundabouts are likely to be the best solution.