I think that stuff is too brittle, the first stick or rock that gets kicked up off the road will probably explode it. Maybe use the galvanized thin gauge steel (although it will rust out in a season or two)?
Below is a link to what I used for my belly pan. It's a thin, heavy-duty form of coroplast that is super strong and comes in small enough pieces to fabricate the belly pan out of easily without being so bulky you can't install it. 2 bucks a sheet equalled a 6 buck belly pan on my Insight.
There should be some available in your area if there's any companies shipping palletized products.
Sign Material