This may sound like a no-brainer, but it recently occurred to me that the best way to reduce motor-traffic, encourage transit use and cycling, etc. would be to have large parking garages near the off-ramps of highways. That way, drivers could basically exit the highway by entering the parking garage. Airports often work this way but I can't think of any cities that induce people to leave their cars at the highway exit and travel further by bus, bike, etc.
One big advantage I can see to using big multistory parking garages is that a bike-share/rental could be located at or near the top, which would be a boon for people parking and then riding away on a bike. If several shopping, meeting/business, and residential areas would be located in different directions from the garage, people could basically coast to their destination. The bikes could be returned at the ground level, where a pulley system could be used to hoist them back to the top of the garage.
Even though you'd still have to pedal around after reaching your initial destination, the ability to coast downhill at first would give users a good first impression of the area. If biking became a draw for visiting the area and commerce, more businesses would want to position themselves within biking distance and the bikable commerce area would expand in this way.