Visibility

Perhaps the most important element affecting safety at rural intersections is the visibility of the intersection itself. Roundabouts are no different from stop-controlled or signalized intersections in this respect except for the presence of curbing along roadways that are typically not curbed. Therefore, although the number and severity of multiple-vehicle collisions at roundabouts may decrease (as discussed previously), the number of single-vehicle crashes may increase. This potential can be minimized with attention to proper visibility of the roundabout and its approaches.

Where possible, the geometric alignment of approach roadways should be constructed to maximize the visibility of the central island and the general shape of the roundabout. Where adequate visibility cannot be provided solely through geometric alignment, additional treatments (signing, pavement markings, advanced warning beacons, etc.) should be considered (see Chapter 7). Note that many of these treatments are similar to those that would be applied to rural stop-controlled or signalized intersections.