Demystifying the Turning Radius and its Critical Importance to Street Safety

Bill Lindeke explains the turning radius, which he describes as "a seemingly obscure street design detail that governs a lot about our cities." The critical influence turning radius has on the structure and form of communities, however, often goes unnoticed. According to Lindeke, however, a street's priorities can be identified in the characteristics of its turning radii:

"Rethinking radii is important because for much of the 20th century the trend in U.S. cities was to increase the turning radii at intersections to try to accommodate higher speeds. These days, however, there’s a change in direction as more cities are trying to improve walkability. Like many street design variables, there’s an unavoidable trade-off between pedestrian safety and traffic speeds, and the turning radius forms the balance point between these priorities."

So it is that turning radii go unnoticed until a controversy like the recent one in Minneapolis over pedestrian medians, connected to a protected bike lane, at the intersections of 26th and 28th streets and Park and Portland avenues. The medians, installed earlier this year, have created confusion for drivers, who often run over parts of the median. The Minneapolis Public Works Department now plans to remove the medians, citing the turning radius on the street as the reason for the decision.