You know, you're right.
I used to live in Baltimore and life required traversing the Chesapeake Bay in all manner of methods.
For many years I drove through Baltimore's Harbor Tunnel and I don't recall ever seeing a post or huge pillar one.
In fact, when I first saw a pic of that tunnel in France, how those huge pillars were right next to the vehicles and so damn easy to hit...well I was surprised.
But you're right as rain. I've travelled up and down this east coast and I've never seen anything like that tunnel was configured.
In Paris you hit pillars, in Boston the roof falls on you. Quaint local customs.
I've driven through that very tunnel in Paris several times. Probably not as dangerous as you make it out to be at 50 mph. Diana and Dodi's car was going over 100mph, though. Seat belts don't help much at that speed.