There are a few distinct advantages to a vertical carport over the horizontal style. First, you’ll get more structural rigidity with this design, since more support is needed for the panels. There is more structure overall involved with the construction of a vertical style carport, and as a result, the building should be sturdier over the long run.
These models also tend to do a better job dealing with precipitation. Since the panels run up and down, they create a clear path for rain or snow to slide right off. If you live in a climate where large precipitation totals are a way of life, you will quickly come to appreciate the advantage of having a vertical roof on your carport.