Abstract: The proposed design of the Butzek-Troemel Roundabout, or spiralabout, provides a number of substantial improvements over traditional multilane roundabout design principles. By providing a generally outward spiraling lane design instead of a continuously circulating lane design, approach capacity, departure capacity, and circulating lane utilization are all enhanced. Vehicle conflict points are reduced compared to standard roundabout designs with as many approach lanes, thus improving safety. The design provides a viable alternative to traffic signals at significant multilane intersections, and an improvement on the roundabout, an emerging design concept in the United States.