Outside the obvious shadiness of Petrino meeting up with a woman away from either of their residences for a joy ride, dropping her back off isn't too terribly fishy considering Petrino only sustained minor injuries.
However, the crash site was 25 or so miles southeast of town towards the Ozark National Forrest. They were heading back northwest towards town when the accident occurred, so there's no telling how far they went. Even on the outside chance their intentions were innocent, I imagine it's going to be pretty tough explaining this to the wife...