Steve Maxwell had spent most of his recent Thursday lunchtimes downtown selling Indian specialties out of his Curried food truck in the roundabout in front of NBC Tower, but on a late July Thursday he pulled up at about 8:30 a.m. to find three other food trucks already parked in the designated food truck zone.

Technically, this Cityfront Plaza zone is only big enough for two trucks anyway, but three routinely park there. Four, however, was pushing it, and in the late morning an NBC Tower security guard told Maxwell he'd have to move.

"I've been coming here for six months every Thursday," he protested, gesturing to the other trucks — Slide Ride up front, followed by E.leaven and Tamale Spaceship — as if they were interlopers. "Today if I don't get this spot, I'm screwed. I have all this food, and I'll have to throw it all away."

The Curried truck stayed, but at 11:30 a.m. a fifth truck showed up, Windy City Patty Wagon, which, unlike the other four trucks there, cooks its food on board. With not enough room to pull in behind Curried, Patty Wagon was sticking out a bit while owner Danny Herrera tried to persuade at least one of the other truck drivers to move along.

The city ordinance passed in July 2012 calls for trucks to obey a two-hour limit for each of the designated food truck locations. Herrera reasoned that if the Curried truck had arrived at 8:30 a.m. and was fourth in line, all of those trucks had exceeded their allotted time, so Patty Wagon deserved a spot.

Uh, no, the other drivers informed him. That's not how it works. This is Chicago, city of dibs.

"That's how you have to do things in the food truck industry: Get there early, get your spot," E.leaven driver Gerardo Gutierrez said. "Otherwise you won't be able to sell."

The woman behind the Slide Ride window, 19-year-old Annalee Soskin, said she couldn't even drive her truck. She said she and the food had been dropped off at about 11 a.m., with the truck having been parked there much earlier.

"The truck was here to save the spot," she said.

A steamed Herrera pulled away in search of another location, discovering cars parked at the designated food truck spot at Chicago Avenue and Wells Street before he wound up at Chicago and Franklin Street (where cars also had been parked) and began lunch service at about 1 p.m., he said. Herrera called the 311 city service line to complain about the Cityfront Plaza situation.

"Sorry @theslideride @Eleaven @tamalespace101 and @GetCurriedAway we've been patient and friendly, but we had to file a complaint today because you're not abiding by the 2 hour rule in a food truck zone, especially at City Front," Herrera wrote on Twitter and Facebook. "Everyone should get a turn for lunch service there. We've been trying for 2 months to get in there. Not cool, guys."

Said Maxwell of the free-for-all: "It's chaos."

In case you were wondering, no, there's no such thing as a sign-up sheet or schedule for the city's 30 official food truck locations (which the city said it eventually intends to increase based on popularity), and there's no association of food trucks despite efforts to organize one. Certain trucks, though, have struck up alliances to share information and spots (i.e., one covers breakfast and gives way to another for lunch).

What there is is a fledgling, active industry experiencing some growing pains as the trucks try to reconcile their business needs and competitive instincts with the city's efforts to create a workable, user-friendly system. Thirty may sound like a large number of areas for about 120 licensed food trucks, but a vast disparity exists in how the truck owners view the locations' desirability.

No one is fighting on weekdays over the spot at, say, Southport Avenue near Addison Street. Instead, three areas have become truck magnets, luring more vehicles than often can be accommodated: Cityfront Plaza, in Streeterville; 600 W. Chicago Ave. (in front of the big office building that houses Groupon); and in Hyde Park between 57th and 59th streets on Ellis Avenue.

"Oh, my God, it's insane," said Sarah Weitz, who co-owns The Fat Shallot gourmet sandwich truck with husband/chef Sam Weitz. "Now, people are coming like at 6 in the morning, 7 in the morning, they're parking their trucks, they're turning them off, and they're having cars deliver their food. It's just really unfair. There's not enough (good) spots, so we're all going to the same three spots that work."

The Hyde Park location isn't even among the city-sanctioned spots yet appears to be the most popular of all, with 11 trucks lined up there on a recent Friday at lunchtime. That section of Ellis, at the heart of the University of Chicago campus, offers a long stretch of open curbside with few nearby restaurants to compete, and the trucks don't need to arrive in the wee hours to get a spot.

"The University of Chicago is so food truck friendly," said Delano Crawford, Porkchop truck partner. "That's why everyone loves coming out here."

On that same Friday, The Fat Shallot and Caponies Express Italian food truck were doing lunch business in the two designated spaces in front of the Groupon building, while Taquero Fusion was parked on the opposite side of Larrabee Street and Soups in the Loop and Cheesie's Pub & Grub were operating from a surface lot across the street that charges trucks $25 to park for three hours.

Aaron Ramirez, whose Taquero Fusion is one of the older food trucks, said more trucks used to have room to park around the corner on Kingsbury Street before the city created the two official spots on Larrabee. He complained that the city also eliminated other prime spaces when it passed its ordinance, which requires food trucks to park at least 200 feet from any brick-and-mortar restaurant.

"The biggest spot of all was Dearborn and Monroe, and they took that away to put up two bike lanes," he said. Also gone: spots at the intersection of Wacker Drive and Monroe Street and in front of the Aon Center on Columbus Drive at Randolph Street. "Those three areas kept us going through the first three years," Ramirez said.

Ramirez said his truck and two of the other older ones, Tamale Spaceship and 5411 Empanadas, have worked together to try to drum up business at alternate spots, such as one at the corner of Clark and Monroe streets. Yet for two straight weeks, he said, a movie production's boom lift sat in that spot, and police cars had been parked there the three previous weeks.

Weitz said another problem with the Clark and Monroe spot, as well as one at 30 E. Lake Street (at Wabash), is that they're located on the left side of one-way streets, meaning that when most food trucks park there, their service windows open into traffic rather than toward the sidewalk.