Oh it's quite practical, many cities have done it. It just requires standing up to a bunch of selfish assholes who would rather pave over every bit of available space so they can drive around really fast in their giant SUVs while pedestrians and cyclists scurry about on the broken pavement of the 5% of the street right of way given to them, and get run over when they don't get out of the way of the SUVs fast enough.