Fixing Traffic Circles

According to traffic safety records replacing traditional intersections with a traffic circles will have a measurable reduction in property damage and accidents, what these statistics ignore is how frustrating it is to help people navigate a traffic circle.  In the personal experience of the author, knowing which road to exit onto at your first encounter of a neighborhood's traffic circle, effectively describing where to go may cause confusion.  For this article we will look into two potential standardized ways for labeling traffic circles to aid in communication.  The first version of this concept takes inspiration for the how runways are designated, every 10 degree point along the circle of the roundabout has a new value of 1/10th the angle, for example if one of the turn offs from the round-about exits in an easterly direction, it will be 90 degrees off of the true north orientation and be labeled exit 9.  For an exit that turns off towards the southwest, you would technically have the angle be 215 degrees, but for ease of communication it is preferable to use whole numbers, it would be up to the discretion of the city planner whether the number is rounded either down to become exit 21, or rounded up to 22 as shown in the example image below.

Runway Style Labeling of Roundabout Exits

Alternatively the traffic circle could be labeled more simply where each exit is named alphabetically, with A being designated as the first exit clockwise from geographic north.  The advantage of this labeling approach over the runway style labeling is that drivers are more immediately warned that their chosen exit is coming up.  Drivers getting off at exit C know that at exit B they need to make sure they are getting in position to turn off.  The challenge that might face this approach would stem for the need to relabel exits if a new exit is added to the roundabout, but from a practicality standpoint this is a relatively negligible concern.  

Example of the Alphabetic Labeling Approach

Both of these concepts are simply the author's suggestion for how we might improve roundabouts to aid in communications.  Suggestions for improving these concepts or alternative approaches are always welcome.