By Jay Levine

CHICAGO (CBS) — A week after trumpeting a proposed deal to renegotiate the controversial parking meter lease, Mayor Emanuel today gave city alderman the details.

The Mayor claims it’ll save taxpayers a billion dollars.

But according to CBS 2 chief correspondent Jay Levine parts of the deal have some alderman concerned.

The offer of free Sunday parking in return for extended meter hours the rest of the week.

The aldermen are understandably gun-shy. After all, many of them helped Mayor Daley rush through the original lease deal in just three days.

Mayor Emanuel’s giving them 30 days and a two inch high stack of documents to decide whether his proposed agreement makes a bad deal just a little bit better.

“This bad deal is worse than we knew,” said Emanuel.

The company which leased these and all other city meters for $1.2 billion reported revenues of $139 million in 2012, up 29 percent from 2011.

That includes tens of millions of dollars it billed the city for spaces it claimed were unavailable due to disabled parkers, street fairs and construction.

“ And we finally developed a computer and data base system that allowed us to challenge this company that thought we were gonna be played for suckers,” said Emanuel.

The proposed agreement, according to the Mayor, will save the city about $25 million a year, $1 billion dollars over the life of the contract, by closing loopholes the parking meter people used to claw back much of what it paid for the lease.

Most aldermen love the billion dollars in savings, but it’s another provision, making Sundays free in most neighborhoods, in return for extended hours the rest of the week that is raising eyebrows.

“I’m not suggesting there’s anything wrong with free Sundays, but nothings free,” said Alderman Brendan Reilly.

Like Reilly’s downtown ward, where there’d be no free Sundays, and meter hours the rest of the week extended in some cases until midnight.

But even in the 81 percent of the city where you wouldn’t feed meters on Sunday, there are aldermen who say people sitting in free spaces would rob local businesses of parking for customers.

“So these businesses actually lose money and we lose sales tax revenue,” said Alderman Roderick Sawyer. “I think it’s a bad idea.

When asked if the deal would die without the free Sundays provision, Emanuel said, “No I don’t think the deal would die but the point is that free Sundays would not be available for residents for the next 71 years.

According to the Mayor’s figures, taxpayers actually come out slightly ahead by making Sundays free in most places in exchange of adding hours during the week.

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