As Talleyho pointed out, you must not be talking about the Mariposa crossing which is what RVers typically use. Came through there 4 days ago. Only thing to watch out for is that the far right truck/RV lane on the Mexican control side was Xed closed. I stopped and waved down a border guy and he waved me through. Also talked to a newbie in San Carlos who blew right by what is often called Kilometer 21 where you get your permits. Note: it is not at KM 21 and it can be hard to see. Keep your eyes peeled for a sign that says Permits. Good luck.
That bridge has had that sign for years. There must have been another structure. We have gone under it In our Dynasty and the Bluebird. There are long chains hanging from the bridge that used to have a warning sign. We have never touched the chain5. If you are worried stay towards the left but not too far as there are dome trees that will scratch your unit. All the Mexican busses use this route.
Looking closer on google earth that overpass is in fact only 3 meters. I originally got this route from Moisheh, but I suspect that overpass did not exist. I think it was added when the Nogales crossing was expanded in 2016.
