EVANSTON, Ill. (CBS) — The Chicago City Council recently passed an ordinance allowing food truck vendors to expand their operations, and now, the owners of a mobile food operation are hoping to see a similar change in Evanston.

As WBBM Newsradio’s Regine Schlesinger reports, the owners of Beavers Coffee and Donuts, who sell gourmet pastries and coffee from their truck in Evanston, are challenging the law there.

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LISTEN: WBBM Newsradio’s Regine Schlesinger reports

Their attorney, Jacob Huebert, tells Newsradio the city code prevents entrepreneurs from operating food trucks unless they also have a brick and mortar restaurant there.

“They’ve been in Evanston with a temporary permit. They’ve been allowed to do that,” Huebert said. “But they inquired about getting permits to operate there generally, and they were told, ‘Well, you can’t do it, because you don’t own a restaurant.’”

Now, the owners – Jim Nuccio and Gabriel Wiesen – are sung the City of Evanston on the grounds that the law is unconstitutional.

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“That’s not a legitimate governmental purpose, to protect a private, special interest group and enrich them at the expense of everybody else,” Huebert said.

Huebert says the law serves no purpose other than to protect Evanston restaurants from competition.

The Chicago ordinance, approved late last month, still has some restrictions in place with respect to brick-and-mortar restaurants. The trucks must operate no fewer than 200 feet away from any restaurant, despite complaints by food truck owners that such a restriction limits them to remote spots that do not get much demand.

Food trucks in the city are also limited to designated “food stands,” with space for two trucks each, in high-density areas of the city where parking is already at a premium. The mayor’s office said the precise locations of the food stands will by chosen in each ward by the local aldermen, residents, and business community.

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The major accomplishment of the Chicago ordinance was to allow operators to cook onboard. Previously, food trucks that operated in the city could only sell food that had been prepared at commercial kitchens, and could only keep hot food warm on the trucks.