Adaptive signal technology cutting Miami drive time
Miami-Dade is close to completing its first rollout of adaptive signal technology on key county roadways, and new studies that again show reduced average travel times along every corridor upgraded could support a sizable subsequent investment now in the works.
Transportation spokesperson Karla Damian said 284 of 300 traffic signals on 10 of the county’s busiest corridors are now running adaptive technology.
Before-and-after studies of those corridors, conducted using data from the Regional Integrated Traffic Information System at University of Maryland, show:
■A 2.4% to 10.1% reduction in weekday travel time and about 5.9% better weekend travel times at night on Flagler Street between LeJeune and Milam Dairy roads, a three-mile stretch with 12 signals, but an average 3.2% increase in weekday morning travel times.
■A 4.6% to 10.7% reduction in peak weekday travel times on Miami Gardens Drive between Northwest 87th and 67th avenues – a two-mile, nine-signal segment – and an average 5% improvement of weekend travel times.
■A 16.1% to 19% weekday improvement in travel time on US 1 from Southwest 98th Street to 17th Avenue – a 7.6-mile stretch comprising 52 signals – and an average 8.7% improvement on weekends.
■A 9.8% to 12% drop in travel time on a one-mile, nine-signal length of LeJeune Road from Anastasia Avenue to Southwest 16th Street, and weekend improvements averaging 9.1%.
■An average 10.6% weekday travel time improvement on LeJeune Road from Tamiami Trail to Bird Road.
■A 0.4% to 10.4% weekday travel time reduction on SR 826 between Northwest Second and 19th avenues – a two-mile, 16-signal stretch – and weekend improvements averaging 3.7%.
■An 8.4% to 23.6% improvement in travel time on Southwest 27th Avenue from Bayshore Drive to Tamiami Trail – a 2.5-mile, five-signal segment – with about 4.7% reduced weekend travel times.
■A 9.7% to 17.4% drop in travel time on Biscayne Boulevard between Northeast 82nd Street and I-395, a 4.5-mile stretch with 33 signals.
■Southbound weekday morning improvements of up to 15.2% reduced travel times on State Road A1A in Miami Beach on a two-mile, 18-signal segment between 63rd and 88th streets, as well as northbound weekday improvements ranging from 12.2% in the morning to 33.3% at night and average weekend travel time drops of 7.35%.
■A7.1% to 14.5% travel time drop on Northwest 41st Street from the Ronald Reagan Turnpike to Galloway Road – a three-mile, nine-signal stretch – and an average 7.7% weekend travel time reduction.
Information for travel time comparisons of Kendall Drive between US 1 and Krome Avenue, due back this month, is still being gathered, according to a PowerPoint presentation Transportation Director Alice Bravo delivered to county commissioners in a transportation committee last week.
“When you start thinking of different distances that people travel around the county, the cumulative effect is that people might be saving a half-hour or more in each direction,” Ms. Bravo said. “That means an hour a day, five hours a week, and basically we’re helping people get some of their time back.”
More importantly, she said, Miami-Dade’s roadways are becoming more reliable.
“It’s not always time we spend in congestion but also the extra time we allocate to the unexpected conditions that we might find on the roadway,” she said. “That’s also a lost-time factor.”
Normal traffic signals work on pre-timed daily patterns based on engineering and historical data, with directional “green time” varying throughout the day, she said.
Smart signals, conversely, which are powered by computers placed at each intersection and outfitted with various detectors, including cameras, adjust to traffic flow and, when working optimally, maximize vehicular throughput speeds by synchronizing with other upgraded intersections downstream.
“The goal of the synchronization is that [when] you’re driving down the road, you hit more green lights,” she said.
And the tech won’t just help regular drivers. Asked by Commissioner Esteban Bovo Jr. whether the upgraded signals can prioritize police, fire and medical rescue vehicles, Ms. Bravo confirmed they could.
The signals will be able to communicate with those types of vehicles as they approach, she said, and take appropriate action.
“If there’s a red phase, it’ll shorten [it] so a light turns green and the traffic can flush out,” she said. “Or, vice versa, if it’s a green light and a vehicle’s approaching, that green can be stretched out to give the vehicle a chance to get through the light.”
Ms. Bravo said her department continues to fine-tune the signal system at its renovated Traffic Control Center, located on the west end of Miami International Airport, to further increase its efficiency.
In 2016, the center received a $1.2 million “facelift,” with technology added to allow county traffic operation engineers to manage the county’s arterial roadways by monitoring 140 closed-circuit TV cameras and adjusting any of the 2,890 signals throughout the county.
A year later, the county paid Econolite Control Products Inc. $11 million for equipment and services to upgrade the 300 signals. At the time, Econolite was the only state-cleared vendor of adaptive signal equipment.
Three competitors were since approved and will be considered for a pending procurement of additional adaptive technology, said Frank Aira, chief of the county’s traffic signals and signs division.
Ms. Bravo said that purchase “would address the rest of the county.”
And it “could [cost] approximately $160 million,” according to Ms. Damian, who said details are under wraps in accordance with the county’s “cone of silence” hush order.
Whatever the details are, Mr. Bovo said, those upgrades need to come sooner rather than later.
“[We’re dealing with] probably 30 to 40 years of poor planning that’s really come to roost,” he said. “Technology will help. More investment in transit will help. That needs to be the mindset moving forward.”