[rswail]

Maybe provide a fleet of clean, well run, electric, regular scheduled, buses and they won't have to sit in the traffic in their individual cars.

Provide bus depots with car parking in the exurbs so that there is the possibility of short driving commutes to/from the depot.

Use smaller, much more frequent, shuttle buses to pickup/drop off "on demand" between houses and those hub depots, then they don't need the car to get there.