Despite a wild day last Sunday at Circuit of The Americas, stock cars can race in the rain, but there is still homework to be done to help drivers with poor visibility and sketchy conditions.

“I don’t know that any car is ‘good’ in the rain,” said Chad Knaus of Hendrick Motorsports. “Street cars that are designed to be driven in inclement weather, if it’s raining out, it’s hard to see. You slow down, right? That’s kind of what it is. Quite honestly, I felt like our cars performed extremely well in the rain situations. The drivers were able to steer, turn, accelerate, race; I think they performed really well.

“The issue was the spray. So, visibility is difficult. That’s like that in any form of racing or on the street. You’re going to deal with that. So, I don’t think that our car is bad in wet conditions per se. I think it actually performed really well. I don’t think there’s any car that’s really good in the rain when you’re behind somebody else. That’s a tough position to be in.”

The million-dollar question is what NASCAR can do about it? Randall Burnett, crew chief for Tyler Reddick at Richard Childress Racing, acknowledged that the spray is not harmful when the rain is light and the track merely damp. It becomes a problem when cars start throwing spray off the rear during heavy rain and with standing water on the track.

“The bigger concern is when you can’t see,” Burnett said. “It has to do with even something as simple as the design of the rear bumper or anything like that. Tyler ran both races, the Xfinity Series and the Cup Series, and it was raining pretty good in Xfinity Series qualifying. He said the spray off the back of the Xfinity cars was dramatically less than it was on the Cup cars. So, just the subtle difference in the cars from the Xfinity side to the Cup side made a huge difference for him in the visibility.

“There are certainly some things to probably be learned there, and everyone is still learning together. It’s not something we’ve done a whole lot. It’s a big learning curve.”

Tyler Reddick reported the spray was easier to deal with in his Xfinity Series car than on the Cup side. Nigel Kinrade/Motorsport Images

The rear ends of a Cup Series car are high enough off the ground to allow water to come from underneath the cars and off the rear tires. Burnett wonders if having a longer bumper could make the difference.

“The bumper is pretty high on the car relatively speaking to the ground where even on the Xfinity car, the bumper cover is lower to the ground,” Burnett said. “The bumper is taller or longer, you should say, and something as simple as that could be helping reduce the spray. It could (also) be the speed difference. The Cup cars are running quite a bit quicker than the Xfinity cars were there.

“It’s a lot with the drivers wearing full-faced helmets with the visors, and then you got front and rear windows and a defogger system that hasn’t really been developed really well because we’ve only run a couple of races where we’ve had to use them. All these things are things that teams are working on.”

On Monday, NASCAR officials held a wet-weather tire test at Richmond Raceway as they continue to determine whether it’s possible to run in damp conditions on tracks less than one mile. However, maybe there is a lesson from that venture officials can apply to road courses. For instance, Joey Logano, the driver participating in the test, said the mud flap idea helped with what the spray was doing but didn’t eliminate it.

Both Burnett and Logano agreed that the Goodyear wet-weather tire wasn’t the issue at COTA. But Logano wondered if maybe there is something that can be done with the tread.

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“I think the biggest things we realized is when we put slick tires on it, slicks were obviously very slick — the cars were undrivable, but there was no spray,” said Logano. “That means it’s coming from the treads on the tires, so maybe there’s a less-aggressive tread pattern that, one, allows us to have grip. We need to have that as well, but maybe can eliminate some of the spray.”

Another part of the visibility issue was with windshield wipers and keeping the window from fogging up. Burnett admitted the wiper on Reddick’s No. 8 Chevrolet did not work as they thought it would, or the Rain-X wore off quickly.

NASCAR mandates a functioning windshield wiper and taillight, but teams can play with that as they see fit. Particularly the windshield wiper is another area where they want to make sure it isn’t a disadvantage with aerodynamics or weight. At COTA, some drivers had issues with their wipers functioning correctly.

“We’ve got to do a better job of helping ourselves in that circumstance,” Burnett said.

And that’s the crux of the issue with racing in the rain. If the cars are suited to do it, there just needs to be some tweaks to make it better for the drivers to handle and be able to see as well as racing in just light rain or damp conditions and knowing when it’s raining too hard.

“There’s probably an element to that, for sure,” admitted Knaus. “I think the only way to learn is to do. Could some decisions have been made? NASCAR has admitted it. Could single-file restarts a little bit sooner help? Yeah, I don’t disagree. But… just like racing on the dirt, you don’t know that until you do it. And you learn from your mistakes.

“So, it’s an environmental thing where you’ve just got to get yourself immersed in there. You’ve got to do it. You’ve got to get in the environment, understand the situations, and then make decisions as you go. That’s unfortunately what we have to do. I think NASCAR did the best job they could under the circumstances. I feel like they learned a lot and we’ll just grow from it.”