[Don]

So much for the wing being the primary reason for the airborne cars, again coming from " long-time Ford Racing engineer Bernie Marcus ", aerodynamic specialist. Bernie must be right as he has the Blue Oval next to his name. The flip up panels on the roof were designed for inside air to escape, nothing to do with under car air , believe it was Jack Roush's idea. Looks like this topic has gotten additional formal technical analysis. Almost like comparing the lack of aero design of the 50's to 70's to 80's cars prior to the manufacturer's interest in producing a more slippery shape and their modern styling, where even today's manufactured cars have similar styling. The older cars were like bricks , from an aero design viewpoint. From AutoRacing Sport:

" Ongoing tests are directed at preventing cars from becoming airborne when they turn sideways or backward. Keselowski’s flight at Atlanta caused particular concern among NASCAR officials because such problems are relatively rare at 1.5-mile tracks (although Atlanta speeds are seriously fast despite the track size). The switch next week from wing to spoiler is likely to have no measurable effect on holding cars on the ground. Wind tunnel tests and study of videotapes of airborne crashes indicate that the major cause of cars taking flight is the rush of air underneath the car, not the rear-deck wing. Among the solutions, according to long-time Ford Racing engineer Bernie Marcus, an aerodynamic specialist, might be slots in the rear area of the car so that, in an accident, air would have places to escape."

Sometime ago there was a video circulating of a sports car at a European race that was at over 200++ mph on a straight by itself, and the car slowly lifted up and then flipped. Happened a 2nd time and the Team withdrew the cars. The front of the car was designed with aero principles for cutting thru the air

Difficult to compare reasons and consequences/solutions of lift when the cars were previously traveling at 150+ mph vs today's 200 + mph. Corner exit speed, tires, aero design, suspension, obtaining higher HP from the 358 CI engine w/o the restrictor plate , banking, track surface, etc., etc., many reasons for the higher MPH. While spoiler testing has gone well from a driver's viewpoint, the real test will be in actual race conditions

Speaking of sponsors, anyone notice that Greg Biffle's #16 is officially, at least for 3 races at a cost of $1.5 million, known as the " No. 16 U.S. Census Ford Fusion ", Yes, he is required to mention the entire name of the car when being interviewed, probably part of the contract. Census estimated each 1% nationwide improvement in mailed census forms vs having someone visit the residence saves $85 million.