This is very clearly laid out writing - props! Only suggestion is to add 1 more option for the town: pass the cost of excess road maintenance to the owner of t

This is very clearly laid out writing - props! Only suggestion is to add 1 more option for the town: pass the cost of excess road maintenance to the owner of the land where the road goes. At the end of the day, I don't particularly mind if Walmart/the mall want wastefully gigantic lots, so long as they pay for their privilege. The issue is not enjoying the luxury of space, but saddling other people will the bill for it. If these large plots were required to pay extra taxes (much like your "downtown special tax") their property values would be lower, and the corporations would take that extra cost into mind before setting up business. That might result in them concluding "people really like driving to the mall because it's so much easier to haul back a bunch of stuff... we'll pay for the extra roads!", or "gee we really should condense into that old building downtown." Both would be sustainable for the city, and the free giveaway to rural / low density areas would end. That's all that's required... no extra subsidies, no extra penalties. Just aim for neutrality.