Well I appreciate the messages that have been sent.  As far as loosing traction, like they did when the roads was made of dirt, not like today the cars would get stuck in the ruts and high center.  I agree with the statement that we need to move toward more Pirus style car and away from SUV's and trucks.  As a pilot I know the diverence in drag produced from the landing gear and yes the size dose matter.  It is my prediction that as gas near the $4.00 mark we will see a major push toward alternative fuel cars and the SUV will go away like a '57 Chevy.  We need more research into hydrogen fuel cell which are cleaner burning.  I own a hybrid car and I get about 46 mpg.