Why have we never returned to the covered bridges?
Look for the covered bridge in Philippi, WV. And covered bridge festival in Pennsylvania, Civil War troops marched through one of Philip, and he is still in use, I speak of a metal roof on the sides 16 feet high and low metal to 4 feet from the bridge to limit the wind loads.
If you had a deck with a roof of 16 feet, you would be the height of vehicle because trucks are not allowed to be greater than 13 '6 ". I guess the main reason is cost, and the wind factor. Hope this helps.
Commercial Roofing Specialists Inc – Clendenin, WV