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THE DEVELOPMENT OF F1 INSIGHTS, POWERED BY AWS

Pitlane Performance

F1 Chief Technical Engineer Rob Smedley helps break down each of the new F1 Insights powered by AWS in a series of blogs during the 2021 FORMULA 1 season

A Blog by Rob Smedley

The pitstops have become one of the most exciting aspects of Formula 1. They are a true shop window into how F1 is able to find the perfect blend of human performance and technology. To be able to change all four tyres in less than two seconds is an incredible achievement and one which shows how hard each of the F1 teams need to work in order to find perfection.

During my time as Head of Vehicle Performance for the Williams F1 team we went from the slowest pit stops of all the teams to the fastest ever pit stop on record within one year. This was achieved through a combination of teamwork, innovation, technical development and having every single person involved being able to believe and have the confidence that we could be the best. During that period, we were able to find upwards of one second reduction in the stationary pit time and this was a game changer in terms of race strategy and the final outcome.

Each of the Formula 1 teams however put a similar amount of effort into their own pit stops to find even tenths of seconds as this can be the difference between winning and second place. What is not always evident is the amount of time the driver himself can find when we take the whole of the pit stop event. We tend to focus so much on those blistering and amazing 2 seconds that we miss a huge part of the actual pit stop story.

With this new graphic therefore we aim, as usual, to dissect the whole of the pit stop event which will help us to understand what time is being lost and found from the moment the driver dives into the pit lane.

The New Graphic – Pitlane Performance

As said, this graphic aims to get much more behind all of the micro details of the pit stop. For the teams, the pit stop event begins from the moment the driver peels into the pit lane off the normal racing line and resumes when they re-join the racing line, usually back down at turn 1.

The part we are interested in here is all about driver skill – i.e. the part that is outside the wheel change. There are many different aspects to each different sectors of the pit stop event as we will explain in the section below. In each of them the driver can make a significant difference. Quite often, in post analysis, we are able to see the fastest to the slowest times of the pit stop event can sometimes be up to one second. When we think about the effort and investment that is put into finding even 1 tenth of a second in the stationary time pit stop, it is not surprising why the teams work so hard with their drivers to get the whole pit stop event perfect.

Quite often we see drivers being able to pass their competitors during the round of pitstops when the stationary part has appeared to be very similar between the two. More often than not, this is because the victorious driver has done the better job throughout the whole of the pit lane.

In this next section we breakdown each of the individual parts that the driver must concentrate on and then go into detail regarding the modelling methodology.

The Modelling

For this graphic the model needs to look for common reference points between normal racing laps and the in and out laps of the pitstops themselves.

Below is an example of how the speed looks like on the pit straight on normal laps (red) and how that looks when they do a pitstop (blue).

pit_performance_graph_1

It is clear that we have different phases:

  1. Phase 1 – Here the driver is still on the normal racing trajectory within the track but is starting to move away from the optimal racing line as they approach the pitlane entry.
  2. Phase 2 – The driver, after having navigated the first part of the narrower pitlane entry now is required to decelerate down to the pitlane speed limit (80 or 60 kph depending on circuits)
  3. Phase 3 – This phase is between the pitlane entry and the pitlane exit lines. The driver travels down the “fast” lane at constant speed before approaching his pit crew. They then need to brake into the pitstop position where the car is serviced before accelerating and re-joining the fast lane at constant speed.
  4. Phase 4 – The driver disables the pit lane speed limiter at the pit exit and then re-joins the racing line, positioning the car for braking into the first corner.
  5. Phase 5 – The driver now needs to extract the maximum performance from the car in the first corner, bearing in mind that the tyres are not yet at optimal working condition.

 

All these phases are critical due to the amount of time that the driver has to practice them in the build up to the race. Unlike corners and phases on the actual circuit, the drivers have limited time to test them.

The difficulty also arises from the fact that during the in lap the driver is on used/degraded tyres and then immediately after the stop makes a change to a different grip level. They need to find the limit in both conditions. It is for this reason that we include the first corner in the pitlane performance, as it is a good measure of how quickly a driver can adapt to this new situation.

In order to find the right reference for all the drivers we refer to the timing loop. 

The timing loop positions are logged in the car telemetry and tell us exactly where the car was in that instant of time. Timing loops are situated all around the track as well as being found in specific places like the pitlane entry and exit lines.

We are able to use these specific loops in order to define a precise positioning of the car with respect to the pitlane lines and from there we reconstruct the time needed to travel across the different phases reported.

In some cases, the braking into the pitlane is not significant and therefore phase 2 is not existent. This may also be true of braking to the first corner. These are edge cases, but they can happen (for example wet track with the last corner very close to the entry to pitlane, in this case there is not a real braking).

The only positions that are not absolute in space are the beginning of braking to the driver’s specific pit position and the beginning of braking for the first corner (beginning of phases 2 and 5).

We also report the braking distance for phase 2 (the braking into the pit entry line).

We can calculate each of the individual phase times for every pitstop and then organise these within the database as seen in the plot below. On the left we have reported the braking distances to the pitlane entry line and on the right, the time to cover the various phases. The number denoted next to the driver’s name refers to a sequential number of their respective pit stop. 

pit_performance_graph_2

We can clearly see how each driver performed in the various phases. An interesting point and one which shows the importance of this detailed analysis. In the initial phase the two fastest drivers are Max Verstappen and Lewis Hamilton. They complete this section within 0.01s of each other. Out of interest Fernando Alonso matches the same time of the aforementioned drivers and from my time working with him at Ferrari, I can tell you already that he is incredibly talented and skilful in managing the pit lane. All the other drivers are at least 0.2s slower just in this section with the slowest being nearly 1.0s slower than Hamilton, Verstappen, and Alonso.

It's safe to say that even in this short section of the pit lane the competition is incredibly high.

Summary

We've really enjoyed putting this graphic together. What is clear is that the great drivers out on the track also happen to be the great drivers in the pit lane. It's another F1 AWS Insight that gives us all just that little bit more information to be able to engage and enjoy the race. As with the other insights, it gets us further under the skin of Formula 1 racing and allows us into the world of the teams where every millisecond counts especially in the pressure cooker environment of race strategy where the pit stops can win and lose Formula 1 Grand Prix. Enjoy.

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