[Don]

Retrieved the comment from Sports Daily, quoted by the Ford " aerodynamicist " , he must have the experience and credentials to make the observation.

If the wing was a bad idea, however, NASCAR's new racecar in its entirety was an exceptionally good one. The enhanced safety features speak for themselves, from the first real test—Michael McDowell's 2008 qualifying crash at Texas Motor Speedway—to the most recent—Brad Keselowski's airborne excursion March 7 at Atlanta, with an assist from Edwards.

In truth, the return to the spoiler has everything to do with the appearance of the car and little or nothing to do with safety. Though intuition might suggest otherwise, a car is only marginally more likely to become airborne with a wing (as Keselowski's did at Atlanta) than with a spoiler (as Matt Kenseth's Nationwide Series car did at Talladega last year).
The difference between the two is so small, says Ford aerodynamicist Bernie Marcus, that it becomes statistically insignificant.

"It's not the wing," says Marcus, who has spent countless hours observing wind tunnel tests with both wing and spoiler. "It's the air trapped beneath the car (as it spins and travels backwards) that creates liftoff."

So when NASCAR sets out to keep cars on the pavement, it's not a wing-vs.-spoiler issue. That's not to say, however, that switching to the spoiler doesn't create its own unique set of challenges.

The endplates on the rear wing gave the cars substantial sideforce and consequent stability in traffic. Since a spoiler provides no sideforce, NASCAR has compensated with rear quarter panel extensions and a 3.5-inch "shark fin" that can run the full length of the rear deck lid. Marcus says the combination of those two features will reinstate the sideforce—and stability—lost with the removal of the wing endplates.