The Drag Reduction System (DRS) is a controversial driver-controlled device aimed at aiding overtaking and increasing the chances of wheel-to-wheel racing in Formula 1.
The system, which involves the driver opening a flap in their rear wing to reduce drag levels and gain top speed when running within a second of a car in front, was introduced back in 2011. It remains in use with the new rules reset from the start of the 2022 season.
But, as it did when it was first adopted over a decade ago, DRS continues to be a source of contention among F1 competitors and fans.
Why is DRS used in F1?
DRS is primarily an overtaking aid. It was introduced in 2011 to make overtaking easier. It allows drivers to increase straightline speed by dumping rear wing drag through a slot that can be opened when a car is running within one second of the car in front. Drivers can also use the system on practice and qualifying laps, even when running alone on track.
The device is often criticised because by pressing a button to gain a speed boost, drivers are artificially able to gain time on rivals ahead.
Therefore, it is often claimed that this takes away from the skill of pulling off a challenging overtaking manoeuvre. Juan Pablo Montoya – the former F1 driver and double Indianapolis 500 winner famed for his bolshy passes in the era that predated DRS – compared the device to “giving Picasso Photoshop”.
But DRS is not a simple ‘overtake button’ that automatically means getting past the car in front. While there have been plenty of occasions where its power has been deemed to be too great and so passes have occurred well before braking zones on straights, the tool is generally aimed at assisting overtaking when drivers would otherwise be stuck in dirty, turbulent air.
However, as the latest generation of F1 cars have been designed to allow drivers to follow more closely with a reduced ‘dirty air’ effect, many people had hoped this would lead to DRS being dropped. While that is an aim of F1’s sporting bosses in the coming years, the device’s continuing usage remains disputed.
Since wing-produced aerodynamics became an integral part of F1 car performance in late 1960s this has had a direct effect on how closely the cars are able to follow each other.
But as engine parity in the era before 2014 meant teams could rarely rely on a major grunt advantage to start ahead of or overcome a rival car, the smaller performance gaps placed a greater emphasis on the ‘dirty air’ effect in racing.
This is the phenomenon of air that has already been pushed around by one car landing on the front end of a car following behind, leading to unpredictable handling and increased tyre wear due to increased car sliding.
In the era around the turn of the millennium, the ‘dirty air’ problem was so great, teams would often pit a chasing car to try and jump ahead when their leading rival stopped, which significantly reduced on-track passing. This, in turn, was criticised by fans and observers as an inferior F1 racing product.
DRS continued to be used in the turbo hybrid era, which dramatically altered F1’s competitive order up to the end of 2021. From 2022, F1 has returned to ground effect rules to reduce the dirty air effect and increase wheel-to-wheel passing.
While this is generally accepted to have worked, the altered aerodynamics have reduced the slipstream effect. This, allied with the championship reaching greater engine performance parity ahead of a rules alteration in that area of the cars for 2026, means DRS continues to have a major impact in overtaking manoeuvres.
What is DRS and how does it work?
The DRS uses an actuator controlling a flap in the middle of an F1 car’s rear wing that can be opened when drivers push a steering wheel button after they enter a designated part of each track. These areas are known as DRS ‘Activation’ zones. The open flap reduces rear wing surface area and so serves to reduce aerodynamic drag, rapidly increasing straightline speed.
In races, this is allowed when a driver is running within one second of a car ahead – even if this car is being lapped. In practice and qualifying, DRS can be used at will, but only within the set activation zones. Until 2013, drivers could use DRS at any point on track to reduce drag on a qualifying run. This led to teams implementing set-ups that were for perfect use in qualifying, but hampered drivers attempting to race wheel-to-wheel.
The critical one-second gap between cars is measured at specific points before a DRS zone – known as a ‘detection’ point. Here, electronic timing loops in the track surface measure the distance between two cars. If the following car is measured at running less than one second behind, a signal is sent to the car, allowing its DRS to be activated in the ensuing zone.
Typically, the drivers are informed they can use DRS by dash lights activating on their steering wheels. For the car in front, teams generally radio their drivers to warn if a rival is within the vital gap. The attacking driver will manually activate DRS by pressing a steering wheel button – this can be arranged on the front or back of the steering wheel depending on driver preference.
If running with DRS active and the rear wing open, drivers will turn off DRS and shut the flap the next time they lift off the accelerator or press the brake pedal. The steering wheel button also closes the rear wing flap if pressed a second time per activation.
Drivers can choose to close the wing before braking into a corner, if they are concerned about the aerodynamic load reattaching to the full rear wing and possibly leading to corner entry instability.
Drivers do not have to activate DRS if running within one second of another car. Plus, pressing the button too early means it will not open at the desired point, leading to a delay before the wing can then be opened.
DRS cannot be used on the first two laps of a race or after standing or rolling restarts following safety car or red flag periods. The FIA race director officials can also disable DRS at their discretion if conditions are deemed to be unsafe – for example due to rain. A car going off track or dropped debris at a certain point can also lead to DRS being temporarily deactivated in a specific zone.
Defending drivers can only activate DRS if they too are within one second of a car in front. This generally occurs in a phenomenon known as a ‘DRS train’. This essentially undoes the DRS benefit, because it negates the impact of a top speed boost if many cars in a group are gaining and gaps typically therefore remain stable.
It is also common for a defending driver to redeploy their electrical energy usage via the hybrid elements of modern F1 powertrains – this is typically called an ‘overtake’ button, but for some teams this is known as a ‘SoC’ (state of charge) button – to accelerate faster onto a straight. This is typically deployed as a bid to reduce the chance of being overhauled by a car chasing behind with DRS active by the end of an activation zone.
How many DRS zones are there?
The number of DRS zones varies per track and the figure is also determined by other venue characteristics.
Typically, each main straight at every track features a DRS zone. But if a circuit has a particularly poor reputation for passing, additional zones can be created – and these can include runs featuring shallow corners. Examples of such a run would be the lengthy, meandering zones through the final corners and onto the pit straight in Baku or between Turns 9 and 11 in Miami.
At the 2022 Australia GP, the reprofiled track was originally listed with four DRS zones. The thinking behind this was to use two of the zones – the run down the pitstraight and the new curving section that replaced the old chicane in Melbourne – to allow drivers to close in on rivals and then attempt a pass using DRS through the other two zones into corners that encourage overtaking with big braking zones (Turns 3 and 11).
The DRS zone between Turns 8 and 9 at the 2022 Albert Park layout was removed on safety grounds ahead of final practice following lobbying from certain teams. But this is likely to be used in 2023.
Although DRS can be used through corners that have very shallow angles – and at some tracks these curves may not even by designated as official turns by the FIA – it is generally unsafe to run with a rear wing slot open through most corners.
Although the reduced drag would increase top speed, the corresponding lack of downforce severely reduces car control. This can lead to big accidents given DRS zones usually finish at the end of long straights or acceleration zones.
For certain specific corners, the FIA has allowed drivers to attempt to take them with DRS active.
A famous example was at the 2018 British GP – where a third zone running down the Silverstone pitstraight and through the very fast opening two corners was included. But two big accidents at the first corner – Abbey – for Romain Grosjean and Marcus Ericsson respectively followed in practice and the race. For 2019 the zone was removed has not returned to F1 use at Silverstone in the following two season.
The possibility of a DRS failure can lead to drivers being shown the black flag with an orange disc if their rear wings get stuck open.
If this happens, a driver would be required to return to the pits to allow the flap to be manually shut by mechanics and then not used again if it could not be repaired. A famous example of a DRS failure leading to a crash occurred at the 2018 Italian GP, where Ericsson crashed heavily at Monza’s first chicane as the DRS on his Sauber car did not close as expected when he braked at high-speed.
What can drivers do with DRS?
Drivers can only activate DRS when they are in the designated activation zones and when they are within one second of a car in front in races – this includes backmarker traffic.
In practice and qualifying, DRS use is unrestricted other than only being allowed in the designated zones.
What other series uses DRS?
DRS is also used in Formula 2 and Formula 3 on the F1 support bill.
When it was first introduced to FIA F3 in 2017 – when the series was known as GP3 – drivers could only activate and use the system on a maximum of six laps per feature race and four laps for sprint events. Since 2019, DRS usage in F3 has been run in line with F1 rules. DRS has been used in F2 since it was known as GP2 back in 2015, with the series continuing to include DRS when it introduced its new F2 2018 car for the 2018 season.
Other series have previously used DRS in the same way as F1, such as the DTM in the years before it adopted GT3 rules in 2021.
Overtaking aids are common in other motorsport series. But these involve boosting engine performance for a set amount of time each race (such as IndyCar’s push-to-pass and Super Formula’s Overtake System), or as with Formula E’s attack mode, which allows drivers to temporarily run in a more powerful energy deployment setting, while the total amount of time can be different at each race.
