Perusing a few random sites on the internet:
7 Amtrak departures from Sacramento on weekdays that get you to San Diego in between 12 and 20 hours (most are around 12-13). All but one of those departures are on state-funded trains. All but one involve a bus for at least one segment of the trip.
2 Greyhound departures from Sacramento to San Diego that take just under 13 hours.
8 Southwest nonstop flights (1.5 hours), and 10 more that require a change or a stop at various odd places, with potentially much extended travel times.
4 departures on United, all via SFO with a plane changes, ranging from about 3 to about 8 hours.
Departure anytime, driving, expected driving time excluding stops and traffic congestion for Sac-SD (shortest distance is via I-5) is 7:30-8:00. We all know it takes much longer in the real world, with traffic, rest stops, food, and gas stops; figure more like 10-12 hours. The time I did it just to Fresno, it was about 9 hours without major traffic delays. If you have a Tesla, add about 2 hours to that for 2-3 charging stops (probably best case for a EV). If you drive a Chevy Bolt EV, add about 5 hours for charging stops, and schedule a chiropractor or orthopedic visit on arrival due to the horrible seats. [
www.travelmath.com]