Explained: What does a red flag mean and how does a race restart?

Thomas Maher
Red flag waved by a marshal at Suzuka. FIA F1 Japan October 2022

Red flag waved by a marshal at Suzuka. Japan October 2022

Sometimes, F1 needs to display red flags to stop a race on safety grounds. What is an F1 red flag, and how are they used to make races safer?

Just like in normal traffic rules, where ‘green means go’, the opposite also rings true. Once a rarity that was only used in the most draconian of circumstances, a red flag being shown in F1 means that the session/race has stopped, racing is no longer permitted, and drivers must return to the pits with immediate effect.

The red flag is only shown when track conditions have become unsuitable for racing. This could mean something as simple as heavy rainfall, that is dangerous for reasons of visibility or driveability, or perhaps a crash has occurred that requires removal, barrier repair, or a medical/extraction team to attend to a car.

A red flag can even be shown for matters such as loose advertising hoardings, or if a piece of circuit infrastructure needs attention – anything that could be seen as a danger can trigger a red flag stoppage.

The regulations are that, if drivers or any track officials/marshals are placed in immediate danger by the cars continuing to be on track, and the circumstances are such that the track can’t be negotiated safely behind the Safety Car, the session/race will be suspended by the marshals waving red flags, with all circuit flag lighting posts also switching to red.

During a practice session, the red flag does not stop the session timer, meaning the session remains ‘live’ even if drivers can’t take to the track.

In qualifying, a red flag stops the timer at that moment, meaning the remainder of that particular session will resume with the same amount of time remaining as prior to the red flag. However, a badly timed red flag can have the result of ruining a driver’s lap, or prevent drivers from setting a lap time if the timing is particularly unlucky.

In a racing scenario, the red flag means the race is immediately halted, with drivers forced to immediately slow, cease racing for position, and return to the pits to allow circuit officials to address the issue.

What is the procedure if a Grand Prix is red-flagged?

During a Grand Prix, a red flag stoppage results in the pit exit being closed, with all the cars returning to the pits and forming up in single file at the exit, behind the Safety Car. The cars will then be arranged in the order they occupied at the time the red flag was shown.

If any cars are unable to return to the pits as a direct result of the cause of the red flag, ie. a circuit blockage or crash, they can be brought back once the obstacle has been cleared, and will be allowed to resume the position they were in at the time of the suspension.

Crucial wording in the regulations is that the order of the cars will be determined based on the last point at which it was possible to determine the position of all cars.

These cars will be permitted to resume the session. In the example of Silverstone 2022, where there was an immediate first-lap crash, the drivers had not completed any sector of the lap, meaning the race was resumed using the original grid order (minus the retired cars).

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What changes may be made to the cars under a red flag?

The reason a red flag stoppage can have major implications on the outcome of a race is that the rules allow for all cars to be fitted with fresh wheels/tyres – it’s one of several changes the teams are permitted to make during the stoppage.

It can take a significant sting out of a race ending, with an example being Monaco in 2011. Sebastian Vettel, leading the race for Red Bull, was attempting to finish the race on what would be 62-lap old tyres, fending off the attentions of Fernando Alonso and Jenson Button behind. But a red flag on Lap 72 gave him, and his pursuers, fresh tyres and tipped the scales in Vettel’s favour.

Once the cars are stopped in the pit lane under red flags, teams are permitted to start the engine and carry out any directly associated preparation to return the car to racing conditions.

Compressed gasses may be added to the car as needed, while permitted heating and cooling devices can be fitted wherever needed.

While setup changes are not permitted, changes can be made to the air ducts on the brakes, as well as the radiator ducts. The front wing setup can also be adjusted (same as during a pit-stop), while teams can also make changes to the cockpit for the sake of driver comfort (think headrests, pedal positioning etc.).

Like the tyre changes, another controversial permission is that the teams are permitted to make repairs to cars under red flags.

A particularly notable example of this in effect was at Silverstone 2021 when, after the infamous first-lap collision between Lewis Hamilton and Max Verstappen, Mercedes were able to make use of the immediate red flag to get Hamilton’s damaged W12 back to the pits and carry out extensive repairs that allowed him to resume the race and win in his opponent’s absence.

How a Grand Prix restarts after a red flag

Once the track conditions are safe to resume racing, all competitors will be given an official restart time. This is essential to allow the mechanics to get the car fully ready, and disconnect the car from any support ancillaries that may have been plugged in.

When the five-minute signal is given, all cars must have wheels fitted, with tyre blankets disconnected from their power supply. Any car that doesn’t comply with this will be given a penalty.

With two minutes to go, any cars in between the Safety Car and the leader, in addition to any lapped cars, will leave the pit lane and do a lap at reduced speed. They will then re-enter the pitlane and join the line of cars, without overtaking being permitted on that lap.

With one minute to go, the one-minute signal is given – all engines must start with all team personnel and equipment out of the ‘fast lane’ of the pit lane by the time the 15 seconds signal is given. The one-minute signal also marks the point at which Race Control must have told the competitors whether the race will resume with a Standing Start or a Rolling Start.

Once the light goes green, the Safety Car will lead the line of cars back out on circuit for at least one lap. This lap is included in the race duration, but overtaking is not permitted (with the exception of if a car has a problem on track or a driver slides off etc.)

A Rolling Start decision can be taken if circuit conditions are unsuitable, for reasons of safety, for a standing start. This refers to wet-weather conditions or concerns over visibility, and means the drivers circulate behind the Safety Car until told otherwise.

Once the decision to resume racing is made, the Safety Car will indicate racing will resume at the end of the current lap by switching off its roof lights, with the lead F1 car then given the authority to control the pace of the field while the Safety Car returns to the pitlane.

The Rolling Start used to be the default method for restarts but, in 2018, provisions were made in the Sporting Regulations to allow for a Standing Start.

This is the default method for restarts, provided Race Control do not have any concerns about track conditions or visibility. As such, in a dry-weather race, a standing restart is a near-certainty.

For this method, the Safety Car withdraws to the pits at the end of the very first lap on track, with the lead F1 car responsible for the pace of the field while the Safety Car withdraws.

Circulating back around to the grid, the drivers form up on the grid in the order they were circulating, with the full start sequence from a race start then used to resume the action.