NASCAR explains reasons behind new Cup aero rules coming for 2019

The rules are based on the design used in this year's Charlotte All-Star Race, which won praise for improving the racing during the event.

Two versions of the aero package will be used, each tailored to specific tracks, but with the intention to reduce horsepower and add downforce to stabilise handling, as well as help cars follow each other.

NASCAR has previously faced criticism for poor racing on 1.5-mile circuits, with the aero package set to be used on tracks such as Atlanta.

"Let me dispel the myth that NASCAR is interested in pack racing everywhere," said Steve O'Donnell, NASCAR's executive vice president and chief racing redevelopment officer.

"That is not at all what this package is. This package is to take the best from the short tracks, the best from the superspeedways and meet in between.

"Do we want more cars on the lead lap? Absolutely. Do we want tighter racing? Absolutely. Do we expect three-wide every lap? No.

"The best drivers and the best teams are still going to win the race."

O'Donnell added that the rules have been set in collaboration with OEMs, including those not currently racing in NASCAR.

"When we talk about growth, that means being more relevant, potentially introducing more technology into the sport, especially around the engine," he said.

"As we've had discussions with new OEMs, the direction we're going in for next year's rules package really opens up a variety of options for us to bring in new OEMs, [and] to have our current OEMs potentially accept a new direction.

"So a lot of thought went into this - this isn't just a 2019 rules package, it's something that we believe really sets us up for the future.

"Not only for our current partners, but growing the sport, which hopefully leads to more healthy ownership as well where we can bring some new OEMs in."

It is now expected to be several years away from competition and the 2019 aero package could influence its direction.

"When you look at the next-gen vehicle, if you look at what people are driving on the street today in terms of horsepower numbers and different relevancy options, in terms of electrification or partial electrification, all those things become an option for you," said O'Donnell.

"Do I ever think we'll be a hybrid racing series? No.

"But this allows for [making] some tweaks to the engine package down the road if we wanted to when we race around this horsepower.

"So it gives us a real look not only to what we believe will be better racing than we've produced in the past but it also opens it up to new OEMs, opens it up to new technologies, and really puts us on a great growth path for the future."