Semis go through the tunnels all of the time, and most of them are at the max of 13.6'. It looks close, but it doesn't seem to be a problem.
Cutting off your propane before entering 1 of the tunnels in the Hampton Roads area of Virginia is not a problem either. There are mandatory pull-offs manned by VDOT personal that vehicles that are carrying hazardous or propane are required to stop at. The VDOT worker will confirm that your gas is off, or just ask you. You see RVers going back to cut the propane off, as well as stopping on the other side of the tunnel to cut it back on. It is a way of RV life when traveling through VA. tunnels. Personally, I like it......just another way to make our roads safer.
BTW, if you cut the propane off without turning the fridge off, the fridge is going to try to continue to light. I take the time to open up the camper and turn the fridge off before turning the propane off. It is also a good time to check that everything is riding OK inside and out, check my axle temperatures, hitch, and just stretch the legs a little.
After a neighbor warned about the wind turbulence of going though the tunnels, I pinched the seat of my truck the 1st time I went through. Wasn't bad at all. Makes you a little more aware of staying between the lines, though.......it is close, but not a problem.
Chap , DW Joy, and Fur Baby Sango
2006 Ford F150 Super Cab 4x4
2008 Surveyor 263