Traffic circles are raised islands, placed in intersections, around which traffic circulates. Stop signs or yield signs can be used as traffic controls at the approaches of the traffic circle. Circles prevent drivers from speeding through intersections by impeding the straight-through movement and forcing drivers to slow down to yield. Depending upon the size of the intersection and circle, trucks may be permitted to turn left in front of the circle.
The magnitude of reduction in speed is dependent of the spacing of traffic circles between points that require drivers to slow. On average traffic circles achieve a 11% reduction in speeds and a dramatic decrease in collisions by 71%.
Advantages
- Very effective in moderating speeds and improving safety.
- Can have positive aesthetic value.
Disadvantages
- If not designed properly, difficult for emergency vehicles or large trucks to travel around.
- Must be designed so that the circulating traffic does not encroach on crosswalks.
- Potential loss of on-street parking.
