We've already tried various solutions to this problem and the one that seems to work best is to gradually degrade the road experience for motorists as demands o

We've already tried various solutions to this problem and the one that seems to work best is to gradually degrade the road experience for motorists as demands on the space go up. First we take away street parking and left turns. Then we take away stopping / idling. Then we make carpool / high occupancy vehicle lanes and bike lanes. Then we convert lanes into transit lanes only. Then we completely prohibit cars / motored deliveries during rush hour. The last one is usually the hardest politically to get through because it is a major disruption to many businesses, but it is quite effective and usually leads to a great number of people switching to mass transit and bike lanes.