no margin of error, like seriously

We picked up the pups from doggie day care boarding and headed back to Jupiter.  We take the Garden State Parkway en route to New Jersey Turnpike and I 95 to bypass NYC.  Oh buddy.  Do not take your class A on this freeway unless you have a blindfold.  There are at least 40 (!) overpasses of unknown clearance. Our RV is 12 feet 10 inches to the top.  It's 8 feet 6 inches wide.  Our super fancy, super $$$ special RV edition Garmin seems to think this route is just fine. Overpass after overpass we swore we were going to whack the top of the RV right off.  40 overpasses later and two 8 foot 5.5 inch wide toll booths were were out of danger. Although, Wikipedia says the maxium toll booth width is 8 feet! I have no idea how he made it.  The maximum clearance, we later learned, was 14 feet. And also learned that in some spots, the overpasses are as low as 11 feet 2 inches.  The whole time on that stretch of highway, John was crouched over going OMG! We are gonna hit! and We're gonna hit!   RAHHHHHHHHHHHHHHHH!  Over and over and through and through it was a heart attack every time!  John kept eyeing the shape of the overpasses, if they leaned to the right, he veered left. If they leaned to the left, he veered right to get maximum clearance.  WHAT A FREAK SHOW of a highway!