It is a huge problem cause we had great functional cities with lots of housing and most had trams on every majory roadway. We made huge mistakes destroying multi story buildings to pave surface level parking lots. This problem was decades in the making and will take decades to build out of, but thats what we'll have to do if we want to fix it. There is no magic undo button.

Things cities can do to start improving today inckude upzone residential neighbourhoods to make midrise multi units possible to build. Allows mixed use zoning where residential moxes more with light comercial and restaurants. Restrict new developments on the edges of the city to meet minimum density requirements and transit access standards. Update fire/building codes to make single staircase buildings safe and viable. Do a street assement when repaving roads to determine if dedicated transit, cycling, or pedestrian lanes should replace some car lanes.