Pit Exit

Formula 1 Data, Analysis and Opinion.

The Best Place for a Pit Stop

Formula 1 is always pushing back the boundaries of what is possible and recently this has become particularly evident in pit stops.

Prior to 2010 the length of a stop was essentially determined by the time it took to pump fuel into the car, but since the removal of this constraint it’s the teams’ performance that’s now the limiting factor. As always, Formula 1 has driven this competition to the extreme: the pit crew have essentially become athletes in their own right, with diet and training plans to keep them fit and sharp, and relentless practising throughout the season. This drive for performance culminated in Red Bull’s world record pit stop of 1.923s for Mark Webber in Austin last year.

Given that races can be won or lost in the pit lane, it’s no surprise that teams value their performance here. So which of the teams did the best job in 2013?

Which pit stop time?

Depending on what you’re interested in there are several ways you could choose to measure a pit stop.

If you’re training your pit crew you’re probably most interested in the length of time the car is stationary. However this doesn’t really tell the whole story of a stop – a good crew will already have their pneumatic guns over the wheel nuts before the car comes to a halt, and it ignores the part the driver plays in picking their breaking point just right.

On the other hand, someone looking at the race strategy would be more interested in the total time lost compared with continuing on for another lap. This would include the time lost peeling off into the pit lane and accelerating out of it, as well as the time spent in it. You might even want to consider the time lost around the first lap while warming up the new tyres. But not only is that taking things too far, it’s taking us further from the purpose of this study – to look at the teams’ relative performance at pit stops.

The measure we’ll be using here is the total time spent in the pit lane, which will be referred to as the “Pit Lane Time”, and the most important reason for using it is that this is the data available to us, published by the FIA.

Even if our hand wasn’t forced by the data available, the Pit Lane Time would be a good choice to use. It includes the contributions of the entire pit crew and the driver (who must stop the car in the right place, at the right angle) which is what we want to measure. And even though a large fraction of the time measured is spent crawling along the pit lane, this is done under a speed limiter, so comparisons between teams are fair.

Here’s the Pit Lane Times from the 19 races:

The Pit Lane Time [s] of every stop during each race of the 2013 season

The Pit Lane Time [s] of every stop during each race of the 2013 season

 

Generally, each race tells a similar story – an quick “everything goes right” peak with a “stuff hits the fan” tail on the high side. Some races had more eventful pit lanes (e.g. Malysia) than others (e.g. Hungary). You can also see a reduction in the number of pit stops between the early and later halves of the season after Pirelli toughened up their tyres, following Silverstone.

The one remaining challenge is to make the times comparable between races. Since each pit lane is a different length (reliable values for which I could not find) and three different speed limits were in operation over the season (100km/h before Hungary, 80km/h after Hungary, and 60km/h in Australia, Monaco and Singapore) the Pit Lane Time can be quite different from one race to the next.

To do this we’ll use the difference between a Pit Lane Time and an average for the race. Since the race’s mean Pit Lane Time would be strongly affected by the number of  long stops where mistakes occurred, we’ll use the median as our average instead.

(Aside: It is possible to remove differences from pit-lane length and speed by subtracting the Pit Lane Time from drivers serving drive-through penalties. However, despite 22 such penalties being doled out in 2013, there wasn’t one at every race. For the sake of statistics we want to include data from all 19 races, and we want to treat it all the same, so we won’t use that here.)

Team performance in 2013

So here’s the teams’ performance. One normalised histogram for each team, showing the time of their stops relative to the median time for the race:

Each team's Pit Lane Times compared to the race median Pit Lane Time [s].

Each team’s Pit Lane Times compared to the race median Pit Lane Time [s].

 

I guess there’s no surprise to see that Red Bull and Ferrari seem to set both fast times and make few mistakes. Meanwhile the other big teams like Mclaren, Lotus, and Mercedes were regularly pulling off quick stops too, but were also a bit more likely to have a problem. Credit is due at Force India which stands out as being the most consistent amongst the other teams.

While it might seem that pit stops are one area where budget matters less and the smaller teams can compete with the bigger ones, it’s clear that the last four teams in the championship also have the worst four distributions. Given, in particular, what a terrible messy set of stops Williams had, one could conclude that mindset and motivation are playing a big part in a pit crew’s performance. Improvement is also definitely possible at Caterham, who didn’t perform a single pit stop faster than the race median over the entire season.

And the winner is…

While we could stare at those plots all day and argue the relative merits of speed, consistency or ability to recover from a mistake, Formula 1 is a sport so we’ve got to pick a winner. The mean of the above plots seems like a reasonable measure to me (though I did first cut out stops which were more than 10s longer than the race median – it’s probably not the pit crew’s fault after that sort of time):

Position Team Mean (Pit Lane Time – race median) [s]
1 Ferrari -0.37
2 Red Bull -0.33
3 Mercedes -0.28
4 Mclaren -0.09
5 Lotus +0.09
6 Force India +0.45
7 Sauber +0.54
8 Toro Rosso +0.67
9 Williams +1.35
10 Caterham +1.44
11 Marussia +1.11

Formula 1 drivers don’t get to choose which garage they get their tyres changed at (except Lewis Hamilton who tried both Mclaren and Mercedes in Malysia!) but if they did they should go to Ferrari. In a refreshing change from every other measure of performance last season, the Italian team have edged out Red Bull to be crowned kings of the pit lane in 2013!

Analysis Notes

  1. Raw data sourced from the FIA
  2. Drive-through penalties are removed from the data by calculating the median Pit Lane Time for the race, and removing any Pit Lane Times which are more than 2s faster than the median. This removes 22 times – the number of drive-through penalties awarded in 2013
  3. Stop-go penalties are removed from the data individually. A 10s stop-go penalty is indistinguishable from a ~10s stop, so all three stop-go penalties are hard-coded in so that they can be identified and removed.