Each group must find spaces on its map for 1,102 yellow Legos and 436 red ones. Even with toys involved, the game's not easy to play, as a group of locals found when they staged a dry run this week at the Tampa Bay Regional Planning Council.

PINELLAS PARK - Fed up with pell-mell development and traffic jams creeping into your once idyllic neighborhood?

You may have an opportunity to have a say in growth - for the long term.

The region is only going to grow more. Way more. So Reality Check Tampa Bay, spearheaded by the Urban Land Institute and Tampa Bay Partnership, is seeking volunteers for a May 18 exercise to figure out where best to locate homes for the 3.4 million more people expected to be here by 2050 - and workplaces for nearly 1.7 million new jobs.

"We've had lots of interest from elected officials and businesspeople," said Betty Carlin, spokeswoman for the Tampa Bay Partnership, which works to lure jobs to the area. "We're kind of light on the nonprofit folks, the everyday citizen types."

Reality Check Tampa Bay's project manager, Amy Maguire, said there's a particular shortage of people focused on the environment and people "in their 20s and 30s, people who want to live here and raise their families here."

The plan is to invite 300 people to the Tampa Convention Center: 100 each from the public, private and the nonprofit, civic-oriented sectors. Divide them into groups of 10. Give them a map of the seven-county region - Hernando, Hillsborough, Manatee, Pasco, Pinellas, Polk and Sarasota - and leave out county borders to force groups to think regionally.

Then find the best spots to put all those new places to live and work.

For the purposes of Reality Check Tampa Bay - an exercise the Urban Land Institute has conducted in Los Angeles, Washington, north Texas and Maryland - that means each group must find spaces on its map for 1,102 yellow Legos and 436 red ones.

Even with toys involved, the game's not easy to play, as a group of locals found when they staged a dry run this week at the Tampa Bay Regional Planning Council. A little more than a half-hour into the exercise, developer Harry Lerner sounded an alarm as one colleague contemplated piling up Legos near a particularly green part of the map.

"He wants to put a city right next to the Green Swamp!" said Lerner, president of Maxcy Development Group and an executive committee member of Reality Check Tampa Bay.

The same group initially lined up tall stacks of red and yellow Legos up and down the coastline. Then Maguire gently reminded the stackers that they had listed "minimize impact to environment" as one of their guiding principles and suggested hurricane evacuation of all those new coastal residents and workers could be a problem.

By the end of the exercise, the group shortened the tall coastline stacks considerably. But those Legos had to go somewhere. The group ended up creating a new city in Manatee County where Interstate 275 meets Interstate 75, and a new highway the group threw in for good measure stretched from there to the east coast of Florida.

That's one thing Reality Check Tampa Bay will have that the other cities' volunteers didn't. They get ribbons to show their hopes for mass transit and new roads - as well as the Legos.

The traffic-conscious Tampa Bay groups placed those ribbons first for the dry run.

For those who want to participate in the real thing come May, Reality Check Tampa Bay will accept nominations through March 15. The group's executive committee and co-chairpeople will make the final cut. Those who don't make it for the Lego-building stage may get a call later, Maguire said.

"A lot of it is after May 18th: how to build more communication with these people," Maguire said. "That can be translated into some scenarios where we can go out to the people who expressed interest and say, 'Here are some scenarios that came out of this event.' May 18th is just the snowball. We want to go back to these individuals that provide input or interest to add snow so that it keeps gaining more momentum."

Reporter Karen Branch-Brioso can be reached at kbranch-brioso@tampatrib .com or (813) 259-7815.