Requiring each building in a business area to have its own attached parking is a great way to perpetuate sprawl. Successful walkable business districts either use metered street parking, or intercept cars in parking lots at a stand-off distance away from the shops themselves. This amortizes the parking load among the shops.
If that sounds a lot like a mall, it is, but I'd advocate for also removing the zoning restrictions that segregate residential condos from business (a really stupid decision that many American cities keep perpetuating).
Maybe we could place that government parking on the sides of existing roads; we could automate the payment process with small devices mounted on posts that could take coins (or in some places, cards or mobile payments). For people who don't pay, we could have city employees walk around and issue fines for non-compliance...
If that sounds a lot like a mall, it is, but I'd advocate for also removing the zoning restrictions that segregate residential condos from business (a really stupid decision that many American cities keep perpetuating).