Following Kyle Busch’s crash into an unprotected concrete wall at Daytona there was a huge outcry from those in the NASCAR garage. Twitter was full of emotionally charged comments such as ‘SAFER Barriers everywhere now.’ In a guest article for RacingCircuits.info Dr. Diandra Leslie Pelecky, physicist and author of the book ‘The Physics of NASCAR’ explores the question of whether those calls for SAFER Barriers everywhere were in fact correct.
As the extent of Kyle Busch’s injuries became apparent at Daytona, Twitter erupted in angry calls for SAFER barriers to be put up on every wall at every track. An interesting division of sides appeared. There were a small number of people who cautioned that simply plastering every track with SAFER barriers was likely to not only not prevent driver injuries, but might actually introduce new problems. Other people accused this group of being insensitive and “stupid”.
Interestingly, that small number of cautionary voices was made up of people like the folks who write Racecar Engineering magazine, people who have been involved with motorsports safety research and people with advanced engineering degrees.
So let’s be really clear here. While I appreciate the passion with which people responded to the accident, opinion has absolutely no place in science and engineering. We work with facts, realising that oftentimes, we don’t have all the facts we need. In an ideal world, we would have data from collisions at every track in the world, from every angle, with every type of racecar. But we don’t.
It’s fine for fans (and especially for drivers and their teams) to raise their voices and demand more attention to safety, but the average fan (or the average driver) has zero business specifying what those safety measures ought to be. The average NASCAR executive or track administrator doesn’t either. Motorsports safety is a constantly evolving research field and luckily, NASCAR recognises that and works with the top people in the field.
Kyle Busch at Daytona
Let’s start with the obvious. A bare concrete wall at a track where speeds reach 200 mph is difficult to defend. To their credit, NASCAR and the Daytona folks (ISC) promised to rectify that right away. Tyre barriers – which are not ideal, but are definitely better than nothing - were up for the next day’s race.
Racetracks originally put up concrete walls to contain the cars and protect the fans. They weren’t there for driver safety. People don’t question the status quo. It wasn’t until a number of serious accidents in both IndyCar and NASCAR prompted an effort to develop a better wall. I detail the origin and development of the SAFER barriers in my book, The Physics of NASCAR based on my interviews with the barrier developers. The effort was initiated by IndyCar, but gained momentum when NASCAR threw their support (and money) behind it.
Once the technology was developed and proven, NASCAR mandated SAFER barriers on the outside walls of all tracks. It was a long road to development because it was a brand new (and frankly, counterintuitive) idea and everyone wanted to make sure it would work under as many conditions as possible.
The SAFER barrier works by extending the time of impact. It’s much more comfortable to fall on a mattress than a floor because the mattress gives. The mattress absorbs and dissipates energy, so that the energy isn’t dissipated through you.
A NASCAR stock car going 180 mph has approximately the same kinetic energy as stored in 2 pounds of T.N.T. When the car comes to a stop, all that energy has to go somewhere. Energy can be dissipated by skidding (friction between wheels and asphalt), light and sound (it takes energy to make that screeching noise and to produce sparks), spinning (energy is used to rotate the car) and deformation (energy is used to crunch or break things). The key is that you want to dissipate energy any way except through your driver.
A mattress won’t make much difference to a speeding stock car. You need something much stiffer, and that’s the purpose of the SAFER barriers. They’re like mattresses for race cars. They use the energy of the car to deform the barriers and spread out the impact over a longer time. This directs energy away from the driver.
SAFER barriers save lives and this analysis is meant in no way to diminish their importance. But the inventors of the SAFER barriers would be the first folks to remind us that it takes multiple safety devices, working in unison, to protect the drivers (and the crowds). HANS or hybrid devices, helmets, restraints and the car itself are all part of the equation. You can’t address any one of those elements without considering the others. So here, briefly, are some things to think about.
SAFER barriers work best in a specific kinetic energy range. I was surprised when interviewing drivers for my book to find that more than one mentioned that hitting a SAFER barrier at low speed actually hurt worse than hitting a concrete wall. But it’s true. The wall works by giving. If you don’t hit it hard enough, it doesn’t give and then it is just like hitting a concrete wall. This is relevant for a couple reasons.
1. Most tracks host more than one kind of racing series. The kinetic energy scales of those series can vary widely. Any solution has to make the track safer for everyone who races there, not just stock cars.
2. Different tracks have different speeds, so even just within a single racing series, this means different kinetic energies. Compare Martinsville and Daytona, where the maximum speeds are a factor of 1.5-2 different. That means the kinetic energy scales differ by a factor of 2.25-4. That’s a big range. The response of the SAFER barriers can be tuned by using different strength foams and different types of steel tubing – but again, it has to work for all series racing there, not just NASCAR.
Indeed it is clear that SAFER Barriers are not the ideal solution for all corners and all tracks, a good example of this is Eldora Speedway, the half mile dirt oval in West Ohio.
The Midwest Roadside Safety Facility at the University of Nebraska in Lincoln, which invented SAFER barriers recommended the technology not be installed at the facility. "We went over that track top to bottom," NASCAR’s Kerry Tharp explains. "There were some recommendations they made to improve the safety features of it. Those have been done. I do know the consensus recommendation was do not install SAFER barriers because it could reverse what you want because of the way the dirt is."
In 2012 NASCAR Director of Safety Tom Gideon explained that their was no way of knowing how the surface at Eldora would react with the SAFER barriers. "We looked at the track and we looked at the surface. When you’re running on dirt, there’s really no way to make sure the SAFER barrier will act the same way it does on pavement. I think part of that problem is the dirt surface and that you really don’t know how the surface is going react and how much it will pile up against the wall."
Motorsports is dangerous. People are killed participating in motorsports, it happens, especially at the lower levels, where the safety requirements are much lower than in the high-dollar, high-visibility series. But even in NASCAR, even in F1 and even in Indy, there will be serious injuries and – I’m sorry to say – we haven’t lost our last driver to an on-track incident. All you need is that one in a thousand, one in ten-thousand confluence of events.
Don’t tell NASCAR and the tracks that they should cover every conceivable wall with SAFER barriers and then sit back and congratulate yourself for a job well done. Consider for a moment the ratio of people whose job it is to make cars fast to people whose job it is to make racing safer. NASCAR has become so much more proactive about safety in the last years. If I were a driver, I would be lobbying NASCAR to hire more people at their R&D Centre focused on safety, and to support more motorsports safety research at universities and industry.
The FIA has an Institute for Motorsports Safety. It’s a non-profit foundation that centralises safety initiatives and testing and works to get safety innovations on the track quickly.
Maybe it’s time for NASCAR to team up with IndyCar and the FIA to form something similar in the U.S. This isn’t an issue that should come up only after a serious wreck. It’s an issue that needs long-term, on-going commitment and attention. As a fan, I’d pay an extra buck or two on top of a race ticket if that ‘tax’ were earmarked for safety research.
For an overview of NASCAR safety, check out this video I made with the National Science Foundation.
About the author and further reading: Diandra Leslie-Pelecky earned undergraduate degrees in physics and philosophy from the University of North Texas and a Ph.D. in condensed matter physics from Michigan State University. She spent most of her academic career as a professor in the Department of Physics at the University of Nebraska–Lincoln. Read her blog - Building Speed for the latest analysis of the physics of racing.