Roundabouts have been successful in Europe and Australia for several reasons, including the designB s high capacity and fluidity, improved intersection safety, shorter delays and reduced environmental impacts. Though the British and Australian approaches which are somewhat different and have developed different tools for evaluation, each has had successes in implementation and driver acceptance.

Proper signing and marking on the approaches are essential in helping motorists identify and navigate Roundabouts. In U.S. designs, most multi-lane Roundabouts do not use lane markings to identify separate circulatory lanes within the Roundabout.

Multi-lane Roundabouts have greater circulatory speeds and higher traffic volumes compared to single-lane Roundabouts that can make them less inviting for pedestrian crossings.

Vehicle speeds are a primary factor in the comfort and safety of pedestrians and bicyclists. According to the Americans with Disabilities Act (ADA), issues relating to visually impaired pedestrians must be addressed satisfactorily in the Roundabout design process, or the intersection may be excluded from consideration in areas with high pedestrian traffic.

There are eight known multi-lane designs on U.S. roadways that have daily traffic volumes in excess of 20,000 vpd and carry peak hour flows in excess of 2,500 vph. Some multi-lane Roundabouts in England carry more than 6,000 vph. Multi-lane Roundabouts can have entering volume capacities upwards of 40,000 to 50,000 vpd.