Not lower than a 'Vette. Ya never know when that high sewer cap will jump up and bite ya in the a$$.
At least you weren't at an airport during "rush hour" causing a traffic jam with lots of horns honking. Airport cops don't have a sense of humor. I say this because I was in Philly at the airport yesterday where they have about 6 speed bumps in front of the arrival terminals. I think those would accomodate a 'Vette's clearance (barely!)