A test driver, often referred to as a test and development driver, is a racing driver who is employed by a Formula One team to be involved in the development and testing of a particular F1 car but is not involved in the actual F1 race. Test drivers are often placed as reserve drivers in case one of the racing drivers of the team is injured or unable to participate in the race allowing the test driver to take their place in the races until the race driver is able to return to their seat.
Test drivers are usually out of work F1 racing drivers who could not secure an F1 seat in a particular year and opt to act as a test and reserve driver for a team until the time is that they can find a full time race seat. Drivers such as Sébastien Buemi, Jaime Alguersuari, Jérôme d'Ambrosio and Vitantonio Liuzzi are examples of drivers who were in a race seat in the 2011 Formula One Season but could not get a race seat for the 2012 Formula One Season so instead opted to become test and reserve drivers until they have a chance of finding a full time seat the following year.
Many young racing drivers also become test and reserve drivers in F1 in the hope of gaining experience in an F1 car before they make their debut or in the hope of impressing their employers or other teams into being promoted to a race seat in the coming year. Drivers such as Valtteri Bottas, Jules Bianchi and Dani Clos are examples of this in 2012.
Most drivers spend their time as a test and reserve driver for about one to two years before they return to an F1 seat or move on to other series yet some drivers have opted to remain a dedicated test and reserve driver for many years with a particular team and in doing so have become full time test and reserve drivers. Examples of this are Luca Badoer, Marc Gené, Alexander Wurz and Pedro de la Rosa, all of which have spent may years as a test driver without seeking an active role as a racing driver.
Sometimes drivers who have come to the end of their career and want to retire from full time racing opt to become test and reserve drivers for a team after their retirement as a way of staying involved to some degree in the sport. Upon their retirements Johnny Herbert, Jean Alesi, Michael Schumacher and David Coulthard are examples who have done test and reserve driving for a team after announcing their retirement.