I have also seen indoor shopping mall garages have a higher clearance at one end but a lower clearance at the other end. I almost whacked out my Yakima cargo boxes until my passenger told me to hit the brakes! I felt stupid having to go in reverse while there were vehicles behind me trying to exit. Duh!
I'm sure I would be more comfortable in a high top van, but for my parking needs in urban areas, a low top van is way more convenient for me. There are many street spots I cannot park at even with my low top van due to low hanging tree branches jutting out from the curb. It would be no problem for a car to park there, but any regular size van would smack the tree branches. Annoying.