Drag reduction system
The drag reduction system (or DRS) is a form of driver-adjustable bodywork aimed at reducing aerodynamic drag in order to increase top speed and promote overtaking in motor racing. It is an adjustable rear wing of the car, which moves in response to driver commands. DRS often comes with conditions, such as the pursuing car must be within a second (when both cars cross the detection point) for DRS to be activated.
The system is also used in the Formula Renault 3.5 since 2012, Deutsche Tourenwagen Masters since 2013, FIA Formula 2 Championship since 2015 and GP3 Series since 2017. An adjustable wing was also used by the Nissan DeltaWing at the 2012 24 Hours of Le Mans, although with free usage.
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In Formula One, the DRS opens an adjustable flap on the rear wing of the car to reduce drag, thus giving a pursuing car an overtaking advantage of a car in front. The FIA estimate the speed increase to be between 10–12 km/h by the end of the activation zone. When the flap is closed it increases downforce, giving better cornering.
The device can only be used during a race after two racing laps have been completed, and when the pursuing car enters a designated "activation" zone defined by the FIA.
In 2011, the FIA increased the number of DRS zones to two on some circuits featuring multiple long straights. In Valencia and in Montreal, two zones were endorsed on consecutive long straights, whilst in Monza and in Buddh, two zones were created on separate parts of the circuit. Two zones had originally been planned for every race with multiple long straights from Montreal onwards (depending on Montreal/Valencia success), but this was not implemented. However, at the penultimate round of the 2011 season, two zones on consecutive long straights saw a return at Yas Marina.
The horizontal elements of the rear wing consist of the main plane and the flap. The DRS allows the flap to lift a maximum of 50 mm from the fixed main plane. This reduces opposition (drag) to airflow against the wing and results in less downforce. In the absence of significant lateral forces (straight line), less downforce allows faster acceleration and potential top speed, unless limited by the top gear ratio and engine rev limiter. Sam Michael, sporting director of the McLaren team, believes that DRS in qualifying will be worth about half a second per lap.
The effectiveness of the DRS will vary from track to track and, to a lesser extent, from car to car. The system's effectiveness was reviewed in 2011 to see if overtaking could be made easier, but not to the extent that driver skill is sidelined. The effectiveness of DRS seems likely to be determined by the level of downforce at a given circuit (where the cars are in low drag trim at circuits like Monza, the effects may be smaller), by the length of the activation zone, and by the characteristics of the track immediately after the DRS zone.
Rules on use
Use of DRS is restricted by the F1 rules; it is permitted only when both:
- The following car is not more than one second behind the car to be overtaken, which may be a car being lapped. The FIA may alter this parameter, race by race.
- The following car is in an overtaking zone as defined by the FIA before the race (commonly known as the DRS zone).
- The system may not be activated on the first two laps after the race start, restart, or a safety car deployment.
- The system cannot be used by the defending driver, unless within one second of another car in front.
- The system may not be enabled if racing conditions are deemed dangerous by the race director, such as rain, as was the case at the 2011 Canadian Grand Prix.
As of the 2018 season, the drivers are only permitted to use the DRS system in the designated overtaking zones. A dashboard light notifies the driver when the system is enabled. The system is deactivated when the driver releases the button or uses the brakes.
There are lines on the track to show the area where the one-second proximity is being detected (the detection point) and a line later on the track (the activation point) where the DRS zone itself begins.
There has been a mixed reaction to the introduction of DRS in Formula One amongst both fans and drivers. Some believe that this is the solution to the lack of overtaking in F1 in recent years while others believe this has made overtaking too easy. Former Formula One and current Team Penske IndyCar Series driver Juan Pablo Montoya described it as "like giving Picasso Photoshop". The principal argument for the opponents of DRS is that the driver in front does not have an equal chance of defending his position because they are not allowed to deploy DRS to defend. The tightening up on the rules for a leading driver defending his position has added to this controversy. 2018 Scuderia Ferrari driver Sebastian Vettel at one point stated he preferred throwing bananas 'Mario Kart Style' over the use of DRS. 
- Kinetic energy recovery system (commonly known as "KERS")
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- DTM's DRS system will be limited at Brands Hatch – Mattias Ekstrom – Autosport, 14 May 2013
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- Juan Pablo Montoya reckons DRS has made Formula 1 less challenging – Autosport, 26 April 2014
- "F1 2011 Sporting Regulations"
- Vettel: ‘throwing bananas’ from cockpit ‘more fun’ than DRS