IndyCar Math

By Tim Chartier, @timchartier, Davidson College

This Sunday, the Indy 500 will be run as it has almost every year since 1911. The event is billed as The Greatest Spectacle in Racing and considered part of the Triple Crown of Motorsport. For 500 miles, IndyCar automobiles, which can cost as much as $3 million, will be pushed to their limits. A successful race requires a talented driver and highly trained team to harness their power and potential.  

Danielle Shepherd

For Sunday’s race, the Chip Ganassi Racing team qualified all four of their cars for the Fast Nine, giving them a chance at pole position (the inside front position at the start of a race). In the end, the team claimed pole position with the #9 car and Scott Dixon. Let’s get insight into some of the mathematics, computer science, and physics behind the scenes with Chip Ganassi Racing team member Danielle Shepherd, a physics and math double major from the College of Wooster.

Chartier: You work for an IndyCar racing team. First, how does IndyCar racing differ from NASCAR or Formula 1? You were a mathematics and physics double major at The College of Wooster. What role do those fields play in IndyCar racing?

Danielle Shepherd: IndyCar is more similar to Formula 1 than NASCAR when it comes to the physical appearance of the cars. IndyCars and Formula 1 cars are both considered open wheel. This means the suspension is exposed. When drivers hit side to side in open wheel cars, their wheels will actually touch. This is different from a NASCAR which has fenders. If cars touch side to side in NASCAR they will hit bodywork not wheels. The physical appearance of the cars is one major difference. When it comes to track types though, NASCAR runs both oval and road courses. All of the Formula 1 races are either road or street course races. IndyCar is the only series that races all three types of tracks.

Math and physics both play a large role in IndyCar racing, especially in my position as a simulation engineer. Car handling is based on vehicle dynamics, which is just one application of mathematics and physics. Having a solid understanding of vehicle dynamics helps me improve the simulations that I run each weekend. There is a lot of math and physics that goes into the development of a simulation. From the way the tires interact with the road to the force of the springs on the car, the suspension layout, the tires, and the dampers, there are a lot of equations that describe an IndyCar. There is also a lot of math that is used to process the data that is received from the car. There are many sensors on the car that are constantly logging information. Taking the data from these sensors and processing it with equations can help provide an analysis of the performance of the car. 

Chartier: You work as a Simulation Engineer at Chip Ganassi Racing Team. What do you do in your job?

Danielle Shepherd: My main job is to provide models that help the race engineers make informed decisions about changes that are made to the race car each weekend. To start, I take data from the previous event at that track and use it as a baseline. I adjust parameters on the models that I generate so that they correlate to the actual data generated by the car on the track. Once the model is well correlated to actual data, the setup on the car can be shifted from the previous configuration to the new configuration. From there, the model can be used to help the race engineers generate ideas of things they might want to try on the cars before the race event even begins. After we arrive at the event, the simulation can be used to help the race engineers make decisions about how to help the drivers. For instance, if the driver is struggling through a certain corner, the sim can help the race engineer decide which change will help the driver in that corner without compromising the car performance in the other corners. In addition, the simulation is also used to help predict what gears should be run in the car. Weather and wind changes between sessions can have a major effect on the speeds and gearing for a car. These changes in wind and weather are run through the simulations to help come up with the best gearing strategy.

Chartier: You've also been a member of the pit crew. Can you talk about that?

Danielle Shepherd: Starting at the beginning of the 2021 season, I joined the over the wall pit crew at Chip Ganassi Racing. I am the tear off attendant for the #10 car of Alex Palou. With the addition of the windscreen for the 2020 race season, there are now tear offs on the screen which are removed during each pit stop to provide the driver with a clear view. Tear offs are plastic film pieces on the windscreen. Multiple layers of these films are installed on the windscreen of the car before each race. There are no windshield wipers on the cars so this is the only way to move dirt and debris that accumulates on the wind screen. With Alex Palou's victory at the 2021 season opener at Barber Motorsports Park, I became the first female in the IndyCar to be part of the pit crew on a winning car. Hopefully, I am just the first and many other women can add their name to this list in the future.

Danielle Shepherd during a pit stop. Danielle is the pit stop crew member closest to the wall on the right of the picture. 

Chartier: You are on the road about every other week during the race season. Help us envision that part of your life. If we tune into an IndyCar race, what are you doing to help your team?

Danielle Shepherd: Travel is part of being a member of an IndyCar team. Some things have changed over the past year, just with COVID and the state of travelling. Events were more condensed last year, and this schedule has continued for this 2021 season as well. At this point, we leave for an event on Thursday or Friday. Then, depending on the schedule, we are typically on track for multiple sessions, which include practice and qualifications on Friday and Saturday, and then we race on Sunday. After the completion of the race we head home on Sunday. When the trucks carrying the cars return to the shop, we are back in to work. Depending on the location of the race, that is usually Monday or Tuesday. We then work until the day before we travel. When we have events on back-to-back weekends, things can get a bit hectic.

During the race itself, I help with strategy. Strategy is a discussion among everyone on the stand. Since there are different scenarios that can play out, it is helpful to have multiple people weighing in about when we should pit or what tires should be put on the car for the next stint (there are two options at road and street course events). In addition, I run fuel calculations primarily as a backup to the assistant engineer. Fuel calculations are very important so more than one person typically runs them just to provide a second opinion or in case of a computer failure or other malfunction. As of this season, I am also part of the pit crew and I pull a windscreen tear off during a pit stop.

Chartier: How long have you wanted to work in auto racing and how did you make that dream come true?

Danielle Shepherd: I grew up as a race fan. When I was a kid, I would watch the races on TV with my parents. We also went to races at places like Burke Lakefront Airport, Mid Ohio, and Michigan International Speedway. My parents would go to the races and leave me home with my grandparents. My grandad would watch the race, and I would sit with him looking for my parents in the stands. So, I grew up watching racing but I never had thought about making it my career until I went to college. When I started school at the College of Wooster, I thought I was going to be a Spanish and International Relations major. About two weeks after starting classes, I realized political science wasn’t for me. I had always loved mathematics and decided I wanted to pursue that subject. I wasn’t really sure what to do with a mathematics degree but, since I had been a race fan my whole life, I decided that I wanted to engineer race cars. When declaring my mathematics major, my advisor, Dr. Drew Pasteur, asked me what I wanted to do with that degree and I told him motorsports engineering. While he was at a math conference, he heard that you were doing research at Davidson College in mathematics relating to NASCAR. The College of Wooster had just launched a new program called APEX that focused on experiential learning. The goal of the program was to allow students to go out and find their own internships, and then the College would help students obtain the funding they needed. I got approved to spend the summer at Davidson College. Through APEX, I was also put into contact with College of Wooster alumni living in the Charlotte area. The alumna I met actually knew someone who was working for an IndyCar team and was also an alumnus of the College of Wooster. I was able to reach out to him. Through his help, I was able to make connections in the IndyCar industry and also land my first position as a data engineer for an IndyCar team.

Chartier: If a mathematics student also has a dream of working in auto racing, what should they learn and what tips do you have?

Danielle Shepherd: If a mathematics student has a dream of working as an engineer in racing, I would say to make sure they study in school. Working hard in school and capitalizing on all of the opportunities they have in college is the first step to success. Any background or access that students can get to motorsports while in school is helpful. If they can join their local FSAE team (a Formula SAE student design competition), that provides hands-on experience. If there is no FSAE team, finding a local track or a local team that is looking for someone to volunteer and help out is a great way to get started. Any exposure to the sport will help in the long run.

Chartier: Any final words for professors and students of mathematics?

Danielle Shepherd: Racing is fun. It’s my passion; I am glad to have found it. If you have a passion, make sure you pursue it. And tune into the 2021 Indy 500 on Sunday May 30 and root for Chip Ganassi Racing!