Affordances of a Traffic Circle

When an intersection was turned into a traffic circle in the East German city of Erfurt, money must have been tight: except for painting a circle on the ground and adding traffic circle street signs, everything else seems to have been left alone. Unsurprisingly, the new arrangement does not quite work as expected.

Flat street surfaces “afford” driving over them, and that is what many an Erfurter driver does when passing through this traffic circle. Also, the traffic circle signs have been mounted right beneath the yield signs, and judging from the video, both seem to have been mounted rather high up the pole, making them easy to overlook.

Compare the scene from the video with this traffic circle (photo by Richard Drdul):


There simply is no affordance to drive straight through the center of this traffic circle — unless you don’t mind to re-shape parts of your car while doing so. If that still is not obvious enough for some drivers, the signs are placed at eye height and in the line of vision when approaching the traffic circle. Drivers literally have to see them.

Even when on a budget, there are ways to design a traffic circle that is (more or less) impossible to miss. All it takes are big, high-contrast arrows on the ground plus slightly raised curbs around the inner section, as seen here (photo by Zork Minos):