Remember, Bob, that when Elon says he's "fixing traffic" he means "providing a way to avoid traffic for me and those who have enough money to run with me." He's been quoted as saying "I hate traffic" and he has enough money to play with methods to avoid it.

The Hawthorne tunnel is in fact a test article, not a real transit thing. It was bored using a secondhand sewer tunnel boring machine so TBC could get some experience with it and work on upgrades. But it's similar to what he's talked about as connections between Hollywood and Dodger Stadium - small (for quicker construction and less muck to dispose of), one-way (all "pods" to the stadium before the game, returning after), low capacity, a way for those with money to bypass traffic (though the capacity will be miniscule, and one wonders why its Hollywood end is near a Red Line station since it's unlikely that Red Line users could afford it). His original scheme, which ran into some image problems and community opposition, was to bore a tunnel from his Hawthorne property to the executive/private terminal at LAX so he wouldn't have to deal with the surface traffic (doesn't he have a helicopter yet?).

Musk and TBC have no interest in boring tunnels big enough for actual transit vehicles, let alone real highways.