Inside a plain block building on the back half of Orlando Executive Airport, you'll find a group of people constantly taking the pulse of city traffic with the roadway equivalent of heart monitors, X-ray machines and pacemakers.

All are designed to keep circulation healthy on Orlando's main traffic arteries, which form the heart of the nation's ninth-worst congested metropolitan area.

Unfortunately, some of those routes have chronic blockages.

And despite the computers, traffic cameras and timing of signal lights, the flow is not likely to clear quickly. This fast-growing city faces a new problem: another tangle that the Orlando Traffic Management Center must try to solve.

"The new condos downtown," said Tom Allen, Orlando's traffic-operations engineer.

Allen applauds the downtown revival that includes residences and retail shops, but he also sees a new community that will want to get out for work in the morning while an army of other commuters tries to get in or through.

"They are going to want to leave while everyone else is coming in," Allen said, "and then we have to balance and have to compromise the signal times and find a middle ground."

Search for middle ground
It's just the latest in a long series of traffic issues for Allen, who has been trying to keep Orlando traffic moving for more than 20 years and has seen drivers grow more aggressive over the decades.

These days, when he tries to find "middle ground" for commuters in all directions, it usually means uneasy compromise.

More than 165,000 commuters enter Orange County each workday; an additional 375,000 Orange residents have to get to work inside their home county, and, at the end of the day, nobody is really happy about the allotted green-signal time.

"All we can do is tweak it to make it better for one guy on one day," Allen said, "but then we get twice as many phone calls complaining about the other directions."

Inside the traffic-management center, 12 giant video screens line a wall and show live scenes of traffic from about 120 cameras -- all trained on the ebb and flow of vehicles across Central Florida.

Observers stay alert to troubles on the roadways by scanning the various locations. They have their fingers on computer keys that can modify the timing of about 400 signal lights that can mitigate small problems. But they can't make the big ones go away with a keystroke.

Across the nation, studies by the Institute of Transportation Engineers and the Federal Highway Administration estimate that well-timed signals can reduce delays and travel time 10 percent to 25 percent.

If traffic managers see an accident on Interstate 4, they can predict what exits will become jammed with detouring traffic. In response, they gradually can add more green-light time to certain signals to help commuters looking for alternate routes.

Yet despite all the computer programs and commuter studies, traffic managers can't trump one basic equation for the Orlando rush hour:

Too many vehicles. Too little pavement.

An imperfect system
"We've heard that the perfect system is everybody gets a green [light], and nobody gets a red," said signal-systems engineer Chris Kibler, who helps oversee the center. "But since people are going in opposite directions, that's hard to do."

Impossible, actually. Unless you envision a futuristic system that sends vehicles through intersections in a crisscrossing, perfectly timed pattern. Of course, that requires a computerized system that can control the speed of the cars.

Though that's the dream of futurists, Orlando's center is considered modern by current standards. Orange County plans to open a similar center later this year. Florida's Turnpike Enterprise and the Florida Department of Transportation have their own centers in Orange County.

The systems are not perfectly connected, but they can share a lot of information and camera views.

Balancing interests
Of course, big-screen video of traffic jams doesn't mean much to the driver looking to get home. Only one thing does: forward motion.

Many local motorists think traffic signals should be better synchronized. It is one of the most frequent complaints to the Orlando Sentinel's traffic and commuting column.

It's a recurring theme -- part plea, part demand. Or as Millie Grabowski of Orlando put it: "Sync now or sink later."

Allen said he tries to explain the complexities of the traffic-signal system to neighborhood groups. He talks about compromises with neighborhoods that don't want their lights to change more quickly at night because they fear late-night speeders.

Then there's the problem of coordinating busy streets where each traffic signal with turning arrows has several phases, not counting delays for pedestrians crossing late or cars blocking the intersection during rush-hour jams.

On top of that, major roadways such as I-4 and the East-West Expressway must be allowed to dump their traffic onto city roads without risking dangerous backups on exit ramps.

But when that doesn't seem to hit home with the groups, Allen likes to say road congestion is like a sewer line. The pipe can hold only so much. If it reaches its limit, then housing developers must stop connecting new homes to the pipe or risk some very smelly backups.

"But when a road reaches its limit," Allen said, "they just build another parking garage and dump more traffic on the roads at peak hours. Then when it backs up, they turn to us and ask, 'Why won't it work?"