In road racing a hairpin is a type of corner where a racing car turns 180 degrees in a very small area. Such turns tend to be very slow corners, but they are also quite challenging as they usually lead to or end a significant straightaway. Spectators seated at such corners do get a good look at the cars-- and how they'rew working-- thanks to the low speeds. The name comes from the turns distinctive shape, which mimics the traditional grooming item.

Race track designers use hairpins primarily because the courses are located on finite land parcels. In designing a track, you want to include a mix of corners, and a straightaway. Long straightaways offer the best opportunities for overtaking if the car is large and powerful, such as a Formula 1 or Trans-Am car, the longer the straight the better. Hairpins allow the drivers to offer a slow corner and maximize their land use. Because cars leaving the corners are very slow, the hairpin exit can offer a good site for acceleration duels. The entrance may offer opportunities for a late-braking pass. However, drivers often a bit cautious entering a hairpin, as the penalty for a mistake tends to be large. At Mid Ohio Sports Car Course, a mistake at turn three usually plants the car in the gravel trap ending their race. There is a tire wall beyond the pit. The opportunity may beckon, but there are other passing zones where the penalty may be a few lost seconds.