Sometimes I enjoy driving on the roads using an add-on land vehicle.
I am hoping that the team at Microsoft/Asobo will come up with a way to fix bridges so that when you cross over a bridge using a land vehicle, it won’t sink through it.
Thank you for your time! 
Are they landable for instance with Helicopters?
It is usually where a bridge meets a road. They never match, you can’t drive under the bridge 
. Most roads you could probably land on, I have done with a plane. Bridges and the join btw bridges/road are definitely dodgy. You will be able to see the different road surfaces.
I drive on them with a crosskart and the pale grainy ones you sink into. I ported onto a small bridge one time and fell right through it to the surface below. But on the bridge near alcatraz I was able to drive until the huge cabled bridge supports would not let me pass underneath 