The following information comes from several sources that we believe to be correct, but because state laws change, we cannot guarantee accuracy.
Tunnels that go down hill have restrictions to stop and make sure propane is turned off. Tunnels that rise slightly have no restrictions.
Virginia tunnels go down under the water. Propane is heavier than air and in theory could pool in the very bottom of the tunnels. So you need to stop and tell an inspector they are turned off.
Most tunnels that go thru mountains have a slight rise to the middle. That's why you don't have to stop for most of those tunnels.
Baltimore Harbor and Fort McHenry (I-95) tunnels. Alternate route for RVs with propane over the Francis Scott Key Bridge is I-695.
New York/East River:
Between Manhattan and Brooklyn: Brooklyn Battery Tunnel.
Between Manhattan and Queens: Queens Midtown Tunnel.
New York and New Jersey/Hudson River:
Between Manhattan and Jersey City: Holland Tunnel.
Between Manhattan and Fort Lee: Lower level George Washington Bridge (I-95 South) and George Washington Bridge Expressway. Lower level Verrazano Narrows Bridge.
Between Manhattan and Weehawken: Lincoln Tunnel.
Virginia/Chesapeake Bay Bridge/Tunnel: RVs equipped with ICC-approved compressed cooking tanks not exceeding two 45-pound capacity tanks (or two permanently mounted containers with maximum total capacity of 200 pounds) may cross the facility provided that, in the opinion of the toll collector or police sergeant after inspection, the tanks are completely shut off and securely attached.
Texas/Houston Ship Channel: Washburn Tunnel between Pasadena and Galena Park: Maximum of two 7½-gallon containers (30 pounds gas each) or one 10-gallon container (40 pounds gas) of DOT (ICC)-approved type, with shutoff valve at discharge opening. Valve must be closed when in tunnel. LP-gas as vehicle fuel prohibited. 7½-gallon containers (30 pounds gas each) or one 10-gallon container (40 pounds gas) of DOT (ICC)-approved type, with shutoff valve at discharge opening. Valve must be closed when in tunnel. LP-gas as vehicle fuel prohibited.