Quote:
Originally Posted by hipster duck
Has there ever been a serious plan to deck over the trenched part of the Kennedy expressway between Kinzie and Van Buren? There already is an overpass at practically every block. You could probably recoup the decking costs in the sale of land/air rights alone.
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No, because if that were true then it would already be done.
Building over a highway (or railyard, etc) is always significantly more expensive than building on terra firma - there's a construction cost premium in building a deck, long span structures, ventilation, egress, edge conditions, etc. So, the price of the air rights has to be less than or equal to the price of comparable land, minus the construction cost premium. If comparable land is worth less than the cost premium alone, then there's no way to get deck development unless the government steps in with a subsidy.
What I'm saying is, air rights aren't a cash cow. If a government (or private railroad, etc) legitimately wants air rights development, they have to price those air rights appropriately - which is never going to be a huge payday.
Chicago got stuff built over the Union Station tracks because of the immense value associated with that location - over 100,000 wealthy commuters pouring out of Union and Ogilvie stations every morning. Other "air rights" development in downtown Chicago (Illinois Center, Lakeshore East, etc) is really on terra firma, so there wasn't much construction cost premium.
Also, in the case of the Kennedy I'm guessing there's resistance from IDOT as well to any kind of decking scheme that would constrain them in the future. When I worked on a Kennedy-adjacent building just north of Hubbard's Cave a few years back, we had to meet with IDOT who required a 12' setback, because - amazingly - they want to preserve the ability to widen from 10 to 12 lanes in the future.