[aerohead]

SAE recommends an approach angle ahead of the front wheels of 16-degrees.Between the wheels,up to the rocker panel bottom,10-degrees,and behind the rear tires,10-degrees.
GM has adopted a partial solution with cars like Camaro,Firebird,Corvette,allowing the road to eat away the parts which extend too low.The New Beetle also utilizes this technology.
The Ford Probe-IV had active suspension which allowed the nose to drop,and front spoiler to deploy to a ground clearance of only 3.5-inches ( 87.5 mm ) above 40-mph.
Many supercars utilize active suspension to lower the car at speed,then raise it for urban warfare.
Here in Texas,engineers must design for roadkill,where the occasional dog,cat,skunk,possum,raccoon,armadillo,hog,white-tail deer,or tire-gator might take out a car's undercarriage.
Always travel with spices and condiments in Texas,as you never know when you might be preparing a roadside delight!