Right now, we are at the point where a technology is starting to be widely adapted, and people are nervous about it (perhaps rightly so.)
However, I can list a number of things that can save time:
1: Being able to use commute time for something else than watching the taillights of the car ahead. You can have a vehicle which can function as a mobile office, or a bedroom, where with longer commutes, use that time for useful things, be it reading, doing some work, or just going back to sleep.
2: Vehicles can take themselves to get oil changed and inspected. This can save a day's worth of work.
3: Fewer trips would be needed. With a self-driving van, one can call Home Labyrinth, run the credit card, have the van drive to the pickup depot, and come back. This way, if someone runs out of plywood, but still has stuff to do, all it takes is a quick order via a web page, and work can continue.
4: If you are drunk, stoned, tripping balls, high, or all the above, you can still go home in your own vehicle. This in itself will save a lot of time because the police will have to clean up fewer wrecks.
5: Vehicle safety can improve. Cars can be packed closer together, intersections for highways can be made into simple four way intersections, with the cars slowing up or speeding up so vehicles can fly through without having to stop.
6: It saves time parking. Parking of automated vehicles can be handled far more densely than normal parking. Vehicle parking can be moved to the outskirts and not downtown, with a small lot used for quick unloading/loading.
7: It would allow for long trips easily, assuming vehicle auto-fueling. Speed limits can be tossed out the window, with the speed of the vehicle being what it can do, as well as environmental conditions.
8: If you need to carry a lot of stuff to a jobsite, and you just have one person, you can load multiple vehicles.
Of course, there are a few issues that need to be solved:
1: Security. If a blackhat could lock a vehicle's doors and demand ransom, or else it will ram the vehicle (and its occupants) off a bridge, that would be a show-stopper.
2: Third party control. It could be done that cars could be told that they cannot stop at or near areas, or that when someone hops in their car, it takes them downtown for jail processing because of a warrant. Or, some bill collector gets with the car maker and shuts down cars.
3: Corner cases. Thankfully few, but there will be many people out there looking for many ways to get a driving AI to fuck up, so they can play the lawsuit lottery.
All and all, there are issues, but the benefits are quite useful, and far outweigh the risks (which can be mitigated.) Security can be done. For example, the XBox is going on years, with not a single working jailbreak. Similar with the PS4. Even humble old Blu-Ray is still a cat and mouse game, with fewer and fewer decoding utilities available. Third party control can be legislated. Corner cases are relatively few, and that is what insurance is for, as well as dash cams to show if it was a true deliberate action.