A chicane is an artificial feature creating additional turns in a road, used in motor racing and on streets to slow traffic for safety. For example, one form of chicane is a short, shallow S-shaped turn, requiring the driver to turn slightly left and then right again to stay on the road, which slows them down. Chicane comes from the French verb chicaner, which means "to quibble" or "to prevent justice".
On modern racing circuits, chicanes are usually located after long straights, making them a prime location for overtaking. They can be placed tactically by circuit designers to prevent vehicles from reaching speeds deemed to be unsafe. A prime example of this is the Tamburello chicane at Imola, which was placed after Ayrton Senna's death at the original corner. At Le Mans, chicanes were placed alongside the 6‑km Mulsanne Straight in order to slow down Le Mans Prototypes, which with Group C Prototypes went to speeds as high as 400 km/h.
Some tracks, such as the Yas Marina Circuit in Abu Dhabi, feature optional chicanes. Faster cars will take the chicane, but slower cars (such as amateur club racers) might avoid the chicane because they aren't capable of reaching equally high speeds on the straights. Such chicanes are used at Watkins Glen International and Circuit de Barcelona-Catalunya, where there are separate chicanes for cars and motorcycles.
Another example is the Tsukuba Circuit in Japan. A chicane was added after Turn 7, creating a right turn, followed immediately by a left. This chicane is used only for motorcycles. It was implemented to divert motorcycles from taking Turn 8, which is a high speed long sweeping left corner. Turn 8 was deemed to be unsafe for motorcycles, as immediately following this is a slow right hairpin corner. This means riders might still have been leaning to the left when being expected to start braking for Turns 9 and 10.
The term is used in additional types of racing, including bobsleigh and dogleg, to indicate a similar shift in the course or track.
"Mobile chicane" and "moving chicane" are terms often used to disparage slower drivers and vehicles who delay additional competitors. In a few cases they might not move out of the way quickly enough to allow competitors in higher positions (having completed more laps) past, notwithstanding repeated showings of blue flags. This can cost competitors valuable time and championship points. This same term, applied to traffic calming, can refer to the usage of portable devices to create a chicane configuration.
The Yas Marina Circuit's chicanes have become a subject of debate. For example, a few of Formula One's top drivers feel that the chicane after the back straight disrupts the flow of races and impedes overtaking maneuvers.
McLaren Team Principal Martin Whitmarsh feels that placing high speed corners after straights is a better option than using chicanes.
Chicanes are a type of "horizontal deflection" used in traffic calming schemes to reduce the speed of traffic. Drivers are expected to reduce speed to negotiate the lateral displacement in the vehicle path. There are several variations of traffic calming chicanes, but they generally fall into one of two broad categories:
- Single-lane working chicanes, which consist of staggered buildouts, narrowing the road so that traffic in one direction has to give way to opposing traffic
- Two-way working chicanes, which use buildouts to provide deflection, but with lanes separated by road markings or a central island.
Limited accident data for chicane schemes indicate changes in injury accidents (range from -54% to +32%) and accident severity.
A pedestrian chicane is a kind of permanent fence used at a railway crossing to slow pedestrians down and to force them to observe both directions before crossing the railway tracks. While passing the chicane, one has to turn to the left and to the right, increasing the probability of seeing an approaching train. A similar arrangement is at times used at the entrances of parks to impede bicycle or car access.