New data show Chicago’s nascent speed camera system is already lightening the city’s lead feet, but the numbers are also prompting critics to wonder whether City Hall is in for a massive revenue windfall at taxpayers’ expense.

Cameras in nine so-called “safety zones” near four Chicago parks logged 233,886 speeding violations between Aug. 26 and Oct. 9, according to data obtained through a Freedom of Information Act Request.

The cameras are not yet churning out actual tickets, but had they been, those nine alone would have generated nearly $13.9 million worth of citations in just 45 days, according to WBEZ’s analysis. For now, the cameras are generating only warnings to give drivers time to learn where the cameras are - and tap the brakes - before getting walloped with fines.

MAP: Where are the new speed cameras?

And Chicagoans already seem to be riding the steep learning curve city transportation officials had hoped for: Speeding violations have dropped an average of 50 percent at the four sites since Aug. 26, data show.

Those numbers surprised even Scott Kubly, the Chicago Department of Transportation official who’s in charge of the fledgling speed camera program.

“The fact that there’s that many warnings that have gone out is an indication of how big a speeding problem that we actually have in Chicago,” Kubly told WBEZ Thursday.

Some drivers could begin finding speed camera tickets in their mailboxes after Oct. 16, when the 30-day grace period for the Gompers Park cameras on the North Side runs out. Tickets for the other three speed camera sites - at Marquette, Mckinley Garfield Parks - hit the mail Oct. 21. Drivers photographed going between six and 10 mph over the posted limit will get a $35 fine. Get caught cruising any faster than that, and the fine jumps to $100.

In order to “ease the transition,” Chicago Mayor Rahm Emanuel’s administration said in a Friday press release that the city would only issue tickets to drivers caught going faster than 10 mph over the speed limit. It’s unclear how long that will last.

Chicago Mayor Rahm Emanuel’s administration estimates the city will make between $40 million and $60 million from speed camera tickets next year, when Chicago government is facing a nearly $339 million budget shortfall. But the high number of speed violations so far - and the big potential for revenue - has reignited criticisms that the program is more about making money than protecting kids.

“I can not deny that, if those cameras are there, people are gonna slow down,” said 5th Ward Ald. Leslie Hairston, who voted against allowing the speed cameras. “But call it what it is. Don’t try to sell us on the safety of children and parks and schools.”

If speed camera violations continue at their current rate, the city’s take could reach into the hundreds of millions of dollars a year. And dozens more cameras are on the way: The city is aiming to have a total of 105 installed at 50 locations by early 2014, Kubly said.

Alderman John Arena, 45th Ward, who voted against the original speed camera plan, suggests the administration is low-balling its revenue projections, while overestimating the deterrent effect on drivers.

“I think we’re still gonna get caught in the net,” Arena said. “I think $100 million is easy for the system.”

But Emanuel’s administration is sticking to its earlier projections as it bets on a dramatic dropoff in speeding - between 75 and 90 percent - as drivers begin finding tickets in their mailboxes.

“Our number one goal is to slow traffic down, so if we never collect a dime on this, it’s successful,” Kubly said. “It’s absolutely not a cash grab. It’s all about making our roads safer.”

Each new camera the city installs will have a month-long grace period before it starts churning out tickets, and afterward, drivers get one freebie written warning after the cameras are online. The city also plans to put up 20 so-called “speed indicator signs” that tell drivers in real time how fast they’re going, which also slows down traffic, Kubly said.

“We wanna make sure that, no matter where you are in the city, if you’re near a school or a park, that you feel like there could be a camera there,” Kubly said. “And the idea is to create a culture in which abiding by the speed limit is the understood way to drive and the norm.”

Kubly said the program is already having “amazing” success: Speed cameras photographed 7,397 violations on Sept. 10, the first day all nine cameras were up and running. By Oct. 3, violations had already fallen to 3,833.

Since then, the city has installed more cameras at Douglas, Legion, Washington, Humboldt and Major Taylor parks, as well as Prosser Vocational High School, according to a CDOT spokesman.

Alex Keefe covers politics for WBEZ. Follow him @akeefe.

Note: Calculations and figures in this story have been corrected and updated to reflect new data and information provided by the City of Chicago.

Map of locations of Chicago’s new speed cameras  (Updated Oct. 10, 2013)