A hairpin not to be put in your hair, but could raise it.
This is a nice racing add on to any track. What is one thing you see on a road course, the show stopping and brake testing hairpin curve. With the lead in and lead out tracks bringing the cars closer together to require single file running through the curve. Braking too late will cause the appropriate "incident" between 2 cars. If you are recreating a F1, street, or road course, this would be a good addition.