It’s been years since I’ve been through the city bus center but I’m pretty sure cars are not allowed in there. You would have to walk to the street curb, which is not much farther than the walk to another bus. You could also take a bus in whatever direction you want and Uber from closer to your destination.

If you are heading south, the 232 bus which stops on sepulveda at century runs every 30 minutes or so. The Transit app has accurate real time departure information. For directions other than south use the city bus center or the green line.

I predict that walking to and from sepulveda or the Hyatt will become very popular after the people mover is open and car entry is restricted. If you are flying out of terminal 1 or 7 walking is already the fastest way in and out of the airport.