Double-Lane Roundabouts

While the fundamental principles described above apply to double-lane roundabouts as well as single-lane roundabouts, designing the geometry of double-lane roundabouts is more complicated. Because multiple traffic streams may enter, circulate through, and exit the roundabout side-by-side, consideration must be given to how these adjacent traffic streams interact with each other. Vehicles in adjacent entry lanes must be able to negotiate the roundabout geometry without competing for the same space. Otherwise, operational and/or safety deficiencies can occur.