It’s a green light for better traffic flow in Miami

Alice Bravo, Miami-Dade transportation director, at the new traffic signal command center.
Alice Bravo, Miami-Dade transportation director, at the new traffic signal command center.

It used to be that when a traffic light malfunctioned or needed to be reset somewhere in Miami-Dade County, officials had to send someone to the site to fix or reboot it.

Now, it’s all done remotely thanks to a newly renovated $1.3 million county traffic signal command center that formally opened this month near Miami International Airport.

The new command center is part of a streamlining strategy by the director of the county’s department of transportation and public works. Other improvements include the first air-conditioned bus shelter in Florida and a new transit-tracking application that lets riders know how soon the bus will arrive.

“The traffic signals center opened in 1975 and back then there were about 1,200 signals and that system only had the capacity to monitor up to 2,000 signals,” said Alice Bravo, the department director. Now, “the computer servers were replaced so that now we’re up to 3,000 signals.”

Bravo said that in collaboration with the Florida Department of Transportation, the county also has been installing cameras and detectors along major corridors to better monitor traffic.

“We’re installing cameras along our major corridors so we can observe traffic conditions,” she said. “We’re also installing different types of detectors that are going to give us information about how far back cars are queuing, and the travel speeds of vehicles so we can tell if an unusual traffic condition is developing due to an accident or other situation.”

Bravo said that between the county and FDOT, workers have installed 400 cameras. Another 500 cameras are being planned, she said.

The new command center looks like something out of NASA mission control, with giant screens all around. Transportation leaders have divided the county into zones, with one traffic engineer assigned to each zone.

At each work station, engineers have access to not only traffic signal information but also high-resolution images of roads and intersections where vehicles can be clearly seen. The engineer also has access to WAZE, a mobile phone application that provides real-time information on traffic conditions in Miami and other cities in the area.

When an accident happens and traffic engineers see traffic backing up on a particular road, Bravo said, they can change a signal’s timing to better deal with that unexpected flow and keep vehicles from backing up.

The idea is to give drivers as many green lights as possible on busy corridors, she said.

“We’re trying to maximize the efficiency of an individual signal, but we’re also trying to maximize the progression through the corridor so you can hit as many green lights as possible,” she said.

“The idea now is to bring eyes and ears with information to the engineers so they can actually change signal timing and help improve the flow of traffic real time,” she said. “We also look at the weather to see if there are places where a lane is blocked because of ponding and we can report that to a municipality. And if we see an accident, we report that to the fire department emergency dispatch and they will inform the police of the appropriate jurisdiction for further handling.”

Another element of the traffic signal upgrade is the installation of a so-called “controller,” the computer located at each signal, aimed at making the signals “intelligent.”

“We just installed our first adaptive signal controller at the signal right outside of this building,” she said, referring to the command center.

Over the next two months, she added, technicians will install more adaptive controllers along Northwest 36th Street from the traffic signal at the command center in the 7100 block east to 97th Avenue.

Over the next year, Bravo said, staff workers will install the new adaptive controllers along 12 corridors and then the rest of the county.

The adaptive controllers will be able to eventually control the signals and change their timing based on information that now flows to the traffic engineer in charge of a zone at the command center.

“A controller will be able to change operations at a signal and will be able to talk to the other signals along the corridor to maintain synchronization,” she said.