Developing “commuter lots”, or park and ride, on the periphery of downtown to collect motorists before they arrive downtown improves use of public transit, reduces congestion in cities, and benefits both energy consumption and the health of cities. Park and ride facilities, sometimes called incentive parking, are parking lots with public transport connections that allow commuters and other people heading to city centers to leave their vehicles and transfer to a transit system, such as bus, or carpool for the remainder of the journey. The vehicle is left in the car park during the day and retrieved when the owner returns.
Connecting a timely, (you should be able to set your watch to it) mass transit system that simultaneously supports pedestrian travel is the next step. Frequency of ride options should increase during peak hours. If it’s easier, think of the city like a large college campus. When I was at college, we’d park way out by the stadium and hitch a ride to campus on the shuttle, a service that ran every 10mins or so from one end of campus to the other. It made walking not a big deal, even for commuters. In the case of South Bend, just getting me from one end to the other in a short amount of time (less than the 15-20mins it takes me to walk from one end to the other) is a great start to encouraging ridership.
Minneapolis has made a very concerted effort to reduce vehicles downtown by doing something very similar. Their transit system, a latticed effort of buses, lightrail, pedestrian trails, and bike lanes is focused on both convenience and necessity. Read: they took out parking lots and made mass transit a priority.
Also, if we want to encourage biking, more connected bike lanes, more protected bike lanes, and more bike parking.