On Tuesday, NASCAR notified teams in all three of its national touring series that several modifications will go into effect for qualifying, effective immediately.
Teams will be allowed one cool-down unit, connected through either the left- side or right-side hood flap/cowl flap, to cool down the engine. The hood must remain closed, and plugging in the generator will not be allowed. Two crew members will now be permitted over the wall to support the car and driver. Only crew member was allowed in the previous rules.
NASCAR has now banned cool-down laps during qualifying.
"The qualifying is new to all of us, and as we have said over the past several weeks, we are looking at it from all aspects," NASCAR vice president of competition Robin Pemberton said in a statement. "Following discussions, both internally and with others in the garage area, we moved quickly to make a few revisions that will be effective starting with our two national series events at Bristol Motor Speedway this weekend.
"We believe this will only enhance and improve what has demonstrated to be an exciting form of qualifying for our fans, competitors and others involved with the sport. Moving forward we will continue to look at it and address anything else that we may need to as the season unfolds."
Sprint Cup and Nationwide are running at Bristol, a 0.533-mile oval. It's the first short-track races of the season.
Prior to the start of the season, NASCAR instituted a knockout-style of qualifying. Sprint Cup used the new format for the first time at Phoenix International Raceway on Feb. 28.
Since then, teams had been experiencing problems with trying to cool their engines during qualifying. Since NASCAR did not allow the use of cooling units, drivers would make one fast lap and then drive on the inside of the track at speeds that were much slower than those making their fast laps to reduce their engine temperatures.
After last Friday's qualifying at Las Vegas Motor Speedway had concluded, many drivers voiced their concerns about the safety of cool-down laps. Brian Vickers, who drives the No. 55 Toyota for Michael Waltrip Racing, said running the cool-down laps in qualifying was "the most dangerous thing I've ever done in a race car."