2015 IMSA Watkins Glen Analysis

Re-live and analyze the very wet and treacherous 2015 IMSA TUDOR Championship and Continental Championship races at Watkins Glen through data and video.

TUDOR Prototype Class

Here's how the race finished for the entire Prototype class. Although all three podium teams finish on the lead lap, we'll see that we've just scratched the surface of this story.

Let's condense the 2015 6 Hours of The Glen race into 2 minutes! We'll look at the race data from the point of view of the winning #90 Visit Florida car in the IMSA Prototype class.

End of funk.

In the lap chart below, the most notable position change in Prototype class that took place during the race was between the #90 Visit Florida and the #01 Ganassi Racing cars. The winning #90 Visit Florida car did not take the lead until the very late race laps, overtaking the #01 Ganassi Racing. If you watched the end of the video above, you already know how #90 rotated to the top of the charts. If not, don't worry - we'll see how in a moment.

#90 is among the first cars to make its last pit stop. It does so immediately after the 14 min red flag period! #01 has to pit under green near the end of the race which explains the lead change. Moments after #01 leaves the pits, the #007 GTD goes off track (not visible in these charts) and brings out a yellow. This presumably saves #90 from having to pit again, and thus stay in the lead.

When did conditions start getting bad? Shortly after 220 mins (3 hr 40 mins) into the race, we see that everyone's lap times sharply increase. This is due to the beginning of the rains, often times torrential, that would plague the rest of the race and also cause the 14 min red flag period.

The chart below shows the distribution of each driver's lap times, after yellow and pit in and out laps are removed. Each driver's fastest lap time is therefore at the bottom of the chart. Each driver is then ordered left to right according to their fastest lap time.

The majority of the drivers are in Corvette Daytona Prototypes and are among the fastest. The rains cause many drivers to have a large range of lap times, illustrated as tall boxes. The drivers with short boxes presumably did not drive in the rain under green. To find out more about box and whisker plots (you may have seen financial charts use this) see this video.

Finally, here's part 3 of the video race broadcast so you can correlate and compare the data above with what a TV viewer sees. Together, data and video gives you a greater sense of the race story.

8:16 - If you look carefully, on the leftmost edge of the screen you'll see the blue #90 car taking its final pitstop during the yellow session following the red.
9:49 - The announcers discuss pit strategy but all 3 have apparently missed seeing the video showing that #90 has indeed played the very strategy they're discussing.
52:23 - #01 has to make a final pitstop as #90 takes lead.

Continental GS Class

11 GS cars finish on the lead lap with only 12 seconds separating them. We'll see in the data that the finish was under yellow.

Here's the 2015 Continental Tire 150 race condensed into 45 seconds! The race data is customized for the point of view of the winning Stevenson Motorsports car #6 in the Grand Sport class.

IMSA designs the GS class so they can finish typical 2.5 hour races with two pit stops, it designs the ST class so that only one pit stops is required. This reduces pit congestion for races run mostly under green. Unfortunately, in 2015, this Continental race has very few green laps, so most of the leading GS teams only make one stop. The field takes the checkered flag under yellow.

Here's the distributions of each driver's lap times. To find out more about box and whisker plots (you may have seen financial charts use this) see this video.

The CTSC video broadcast. One of these cars is not like the other ones. See it?