Gabriel Wiesen and James Nuccio sell mini beignet-like doughnuts with different toppings from their food truck, Beavers Donuts, in the Loop and in Hyde Park. (Nancy Stone, Chicago Tribune / July 19, 2012)

Ever since Mayor Rahm Emanuel introduced an ordinance last month that would allow food trucks to serve freshly cooked meals around the city, truck owners have been hoping for significant changes.

On Wednesday, the day before a public hearing on the ordinance, the mayor's office released a revised proposal based on "discussions with stakeholders" that some thought would address those concerns.

But food truck advocates were disappointed. Still in place are required GPS tracking of each truck, fines of up to $2,000 for violations and a 200-foot buffer zone between trucks and restaurants in most cases.

The city said the revisions were aimed mostly at clarifying language for smoother implementation. The biggest change to the ordinance would prohibit food trucks from operating in vacant lots.

"The city has presented this ordinance as a boost for Chicago's food truck scene, but it has not responded to any requests that the food truck owners have made since the ordinance was introduced," said Beth Kroger, director of the Institute for Justice Clinic on Entrepreneurship, which supports mobile food vendors.

The ordinance would allow cooking on food trucks (now prohibited), create special zones dedicated to food trucks and allow trucks to operate on private property or in legal parking spaces 200 feet from restaurants.

"The proposed ordinance is a fair, practical and workable compromise to help this innovative industry grow," the mayor's office said in a statement Wednesday.

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Further tweaks could be on the way to address potential congestion issues around designated food truck stands downtown, according to co-sponsoring Ald. Emma Mitts, 37th, who chairs the Committee on Licensing and Consumer Protection. The committee will hold a hearing on the ordinance Thursday. Operational hours also could be cut back from 24 hours a day, Mitts said.

The ordinance builds on a 2010 proposal by Ald. Scott Waguespack, 32nd, that ended up stalling in committee. Waguespack said Wednesday that he would vote in favor of the mayor's plan, despite several concerns, "because they're going to be able to start cooking."

Among his concerns is the use of GPS devices to enforce the 200-foot rule.

"These GPS units are expensive — I've heard $600 or more — and they aren't all that accurate," Waguespack said. "The GPS can't tell within 20 feet where a truck is parked, so how will the city know if the truck is 210 feet from a restaurant or 190 feet? And they are going to issue tickets with these hefty fines based on that? That's troubling."