Why NASCAR Cars Have Flaps On The Roof (Explained)

You may have noticed NASCAR cars have flaps on their roofs. This is a feature that NASCAR mandated in the 1994 season following a series of high-impact crashes. If you’re new to the sport, you may be asking why NASCAR cars have flaps on the roof, and how this makes them safer. 

NASCAR cars have flaps on their roof to act as an emergency spoiler designed to spoil airflow that could cause the car to go airborne. In the past, if a car spun out and drifted backward, there was a chance it would fly into the air and turn over. The roof flaps introduced in 1994 help prevent this.

Below, we will outline a few notable crashes that motivated NASCAR to place flaps onto the cars’ roofs. We will also explore more notable crashes that occurred after the roof flaps were installed, and the steps NASCAR took to modify the flaps to prevent future incidents. 

Why Do NASCAR Cars Have Flaps On Their Roof?

NASCAR roof flaps are a strategic feature that keeps cars from going airborne. When NASCAR cars crash, you may have noticed their roofs flap up and down. And while today’s Next Gen cars have added more downforce than ever before, the roof flaps continue to remain an integral part of the design. 

The roof flap acts as an emergency spoiler for the cars when they turn backward and drift, which could otherwise send them into the air. Just as a rear spoiler spoils airflow at the car’s rear, the roof flap spoils airflow that could launch the car airborne.

You may have noticed that the roof flaps have not always been effective in keeping the cars planted onto the track’s surface. Such incidents have occurred numerous times since their introduction in 1994. Below, you will find a few notable crashes when the roof flaps failed. 

Tony Stewart, 2001 Daytona 500 (Generation 4)

At the 2001 Daytona 500, a huge crash occurred when Tony Stewart got turned around. His car drifted backward and shot into the air. After his car sat on top of another’s hood, Stewart then barrel rolled down the track, hitting multiple cars before the fire-laden vehicle came to rest right side up. 

The car skidded into the infield and came to a rest. Many compared the fiery crash to Richard Petty’s scary flip at the 1988 Daytona 500. Stewart’s crash was one of a few examples of why NASCAR modified the roof flaps before the Car of Tomorrow’s (CoT) debut in 2007. 

Carl Edwards, 2009 Aaron’s 499 (Car Of Tomorrow)

Edwards had what was arguably the scariest wreck during the COT’s life span. Racing toward the finish line, Brad Keselowski got into the back of Edwards, sending him spinning and the roof flaps flying. Another car clipped Edwards, however, and sent him flying head-on into the catch fence. 

The wreck was reminiscent of Bobby Allison’s at the 1987 Winston 500 7 seasons before NASCAR implemented the roof flaps. That incident completely tore the catch fence, whereas Edwards’ didn’t

But the crash was so impactful that it tore the carburetor before it came to rest on its wheels. A natural athlete, Edwards climbed out of the car and ran across the finish line. Despite walking (or running) away from the wreck, it still demonstrated the roof flaps were not keeping the cars planted. 

Austin Dillon, 2015 Coke Zero 400 (Generation 6)

NASCAR further revamped the roof flaps for the Gen 6 car. But in 2015, Austin Dillon’s Richard Childress Chevrolet spun, causing the roof flaps to disengage, and his car flew over several other cars during the race to the start-finish line

He hit and damaged the catch fence at an estimated 190 miles per hour before the car skidded on its roof down the bank and into the apron. Dillon, however, climbed out of the car and waved to the crowd, suffering just minor injuries. 

But the crash further showed that, even with the flaps engaged, cars were still vulnerable to going airborne and hitting the catch fence. Especially at superspeedways. 

Chris Buescher, 2022 Coca-Cola 600 (Next Gen)

Buescher’s wreck is the only one on this list not to occur at a superspeedway. However, it serves as an example that, even with the improved downforce and tech aspects the Next Gen car brought, the roof flaps still don’t always keep the car planted onto the surface. 

During a major crash at the 2022 Coca-Cola 600, Buescher went for a ride when his car drifted backward and into a spin. While the roof flaps disengaged, the car turned over and barrel rolled nearly a dozen times before resting on its roof. Buescher also walked away from the wreck. 

Spotty Results

Since the roof flaps don’t always work, NASCAR has vigorously continued to try and improve them. Crashes like Stewart’s in 2001 were still common, so when the COT rolled around, NASCAR installed flaps larger than the original ones, now measuring 12 by 8 inches. 

But crashes like Edwards’ were still commonplace. However, some blamed the wings on the CoT, which prompted NASCAR to return to the traditional spoilers during the CoT’s life span. It still didn’t stop the cars from going airborne, so NASCAR tried again with the Gen 6 in 2013. 

That season, the flaps measured 10.25 by 24.7 inches on the left while the right flaps clocked in at 10.125 by 33.5. A huge difference from the original 12 by 8 flaps. NASCAR also programmed these flaps to deploy quicker than their predecessors. 

When Did NASCAR Introduce Roof Flaps?

NASCAR introduced roof flaps in 1994 to add what they referred to as an emergency spoiler in case the car begins to go airborne when it spins and drifts backward. However, its results were and continue to be mixed, as Buescher’s crash at the 2022 Coca-Cola 600 demonstrated. 

Despite mixed results, NASCAR realized they needed to do something following 2 horrific crashes that occurred during the 1993 NASCAR Season

Rusty Wallace, Talladega

The first of which involved Rusty Wallace’s series of flips when he raced Dale Earnhardt to the checkered flag. Upon exiting the tri-oval, Earnhardt accidentally clipped Wallace, turning the car around before it ultimately went airborne, flipping several times and shedding most of its body. 

With the roll cage still intact, Wallace was able to climb out of the car, suffering only a broken wrist. This was just one of several scary crashes for Wallace, all of which occurred before the advent of roof flaps. 

Johnny Benson, Michigan

Benson’s wreck, violent as it was, seemed to have occurred in slow motion when you watch the video of it. After spinning out, his car went backward and drifted into the air before rolling into the infield multiple times and coming to rest on its wheels. 

While the crashes listed in the above section showed the roof flaps don’t always do their job, Benson’s wreck is a situation where they may have kept him planted onto the ground

One major difference between Benson’s crash and those listed above is that nothing impacted the car for it to go airborne. Stewart, for example, crashed in heavy traffic while Edwards went airborne because he was clipped. Dillon was also clipped, while a disengaged suspension is what the Coca-Cola 600 broadcast stated caused Buescher’s flip. 

Benson’s crash shows that the roof flaps may help keep a car from going airborne if there is no further outside impact, like another car or the wall causing the spinning car to flip. 

How NASCAR Roof Flaps Work

Any time you see a NASCAR wreck, you may notice the roof flaps immediately disengage, which is what they are designed to do. When the flaps are disengaged, they act as an emergency spoiler and can prevent the car from going airborne by essentially adding downforce to the car. 

Johnny Benson’s wreck demonstrates what happens when cars drift backward with nothing spoiling the air. You’ve probably seen many cars spin out and try to lift off of the ground, much like Benson’s car did in 1993. However, as they try to go airborne, the roof flaps either keep the cars grounded or, if the car does rise into the air, it prevents them from rising far enough to flip

The cars often drop right back to the track surface because they act in the same way as descending airplanes. They bring the wings down and the plane descends, the roof flaps do the same thing. 

They are also quite secure, tethered only to raise at an acute, and not a 90-degree angle. The angle degree and the tether length is a NASCAR specification mandate. They found that at an acute angle, the cars stay grounded better than at a right or an obtuse angle. 

What’s Next For Roof Flaps

It is clear the roof flaps have done their jobs in general situations when cars turn around and drift upwards, only for gravity to take over when the flaps spoil the airflow. However, the flaps have not been perfect as cars were still going airborne in high-impact collisions. 

The Next Gen car might see more downforce modifications if cars continue to rise into the air and flip, as Buescher’s had. However, if it was the suspension that caught the car, it is unclear whether any roof flap can help keep the car from levitating off the track surface. 

The same thing goes for high-impact collisions. One wreck not included above was Ryan Newman’s 2020 Daytona 500 crash. While the flaps disengaged, the angle at which he hit the wall may have caused the car to inevitably flip. 

However, the crashes that occurred to Carl Edwards and Austin Dillon could have been prevented as they were both just clipped before they flew into the catch fence. 

Final Thoughts

NASCAR cars have flaps on the roof to act as an emergency spoiler in case they spin and drift backward. Since the cars are not designed to drift, they are prone to going airborne. By attaching roof flaps, the car is designed to immediately return back to the track surface instead of flipping.