Considering Gibraltar has a grand total of 34,000 residents, it’s more similar to a rail crossing splitting Palo Alto. Which is the case. Similarly, probably as many people a day use the Fremont drawbridge in Seattle, which yields to boat traffic. I think this class of example is why people would be surprised so few cars would sometimes block air traffic.

Also the 101 has traffic lights in SF, when the freeway turns into Van Ness. If Van Ness had a rail crossing, I’d expect cars to wait on trains.