Third driver

A third driver is a type of Formula One driver. Third drivers do not compete in Grands Prix, but are used by teams as a kind of test driver, normally to help the race drivers and engineers with car set ups.

Third drivers can only be used in Friday practice sessions during a Formula One Grand Prix meeting. Teams that finished in the top four of the previous season's World Constructors' Championship are not allowed to have third drivers.

Having a third driver is usually seen as an advantage to a team. In the 2003 Formula One season (when the third driver rule came into effect, albeit in a different form), Renault opted to take advantage of new rules that allowed them to take part in an extra Friday session with three cars. Renault subsequently had a successful season. Similarly, in the 2004 Formula One season, BAR ran third driver Anthony Davidson and finished second in the World Constructors' Championship. In the 2005 Formula One season McLaren ran third drivers and also had a successful season.

Despite this, not all teams opt to take advantage of the third driver rule, with some teams saying that it was too expensive to run a third car on a Friday.

Third drivers are not always used for performance reasons either. Teams have been known to use third drivers for publicity reasons, sometimes by fielding a local driver. Third cars are also allowed to run in different liveries to the race cars.

Also, on several occasions third drivers have acted as reserves, racing if one of the team's two race drivers is injured or otherwise unable to race.