How Power Steering Affects Lap Times

Brad Keselowski lost his power steering early in Stage 3 of the fall Bristol race. I wondered if we could quantify how much power steering affects lap times.

Turns out we can.

Below is a plot of Brad Keselowski‘s lap times, showing reliable 16 to 16.5-second laps during stages one and two. Keselowski was running 13th when he lost power steering. We can see the impact around lap 293, when his lap times jumped into the 18 to 18.5–second range.

Even a top driver like Brad Keselowski with a car that started on the pole and led 82 laps loses two-seconds per lap without power steering.

NASCAR black flagged Keselowski on lap 307 for not meeting minimum speed. The team took the car to the garage to fix the problem. He ended the race in 34th place, 88 laps down.

The #2 car wasn’t alone in having steering problems. The #33 of Corey LaJoie and the #37 of Timmy Hill also DNF-ed due to steering problems.

Other Thoughts About This Graph

• There’s an interesting two-stage lap-time increase apparent here. That might be due to tires, but might also be the effects of lap traffic. Other drivers’ data (particularly the leaders) may help us see how lap traffic affects leaders’ lap times.
• Power steering systems can fail, but they don’t fail often. Unfortunately, the race results don’t include systems failures unless they force the cars out of the race. Data scraping may help get data on things like unsecured ballast and parts failures. It would be interesting to see if there are more incidents this year due to the unusual circumstances.