More ‘diverging diamonds’ are coming to Palm Beach County, changing how drivers access highways

It’s a universal experience for most drivers, encountering multiple traffic lights before turning to merge onto whatever interstate awaits. But so-called “diverging diamond” interchanges offer a new approach.

Whether a driver is trying to go south on Interstate 95 toward Miami or north toward West Palm Beach, they only have one light before getting onto an on-ramp.

That’s one of the differences diverging diamond interchanges have in comparison with more conventional intersections. They may seem wacky at first — so much so that first-time users may feel as though they are about to drive on the wrong side of the road. But the Florida Department of Transportation is bringing more of these configurations to South Florida over the next several years.

The first one in Palm Beach County was completed a little more than a year ago at I-95 and Glades Road . Four more of them are planned in the county over the next several years, with the next one set to start construction at I-95 and Lantana Road. Broward and Miami-Dade counties also have DDI’s in the works.

FDOT says these interchanges are safer than traditional ones because they reduce speeds and cut out the need for the traditional left turns onto the interstate most drivers are used to.

As defined by the transportation department, a diamond interchange “allows the two directions of traffic on the crossroad to temporarily divide and cross to the opposite side to gain access to and from the freeway more easily.”

Among the diverging diamonds built so far across Florida are ones in Manatee County in 2017, Brevard County in 2019, Miami-Dade County in 2018 and 2019, and Nassau County in 2020, according to the transportation department.

DDI benefits include reduced time sitting in intersection traffic, lower driver speeds and fewer “conflict points” for cars and pedestrians.

Cesar Martinez, FDOT’s district planning and environmental administrator, said conflict points happen “when a vehicle is making a left turn or a right turn and at some point, it has the potential to conflict with another vehicle in a different direction.”

“On a normal interchange, what we call a conventional diamond, when you’re making a left turn out of a ramp, there’s a potential if someone runs the red light, then you can collide with them,” he said.

The off-ramps force drivers to follow a curve, which Martinez said slows drivers down as they approach the ramp’s traffic light. The thinking is that if someone does decide to blow the light, either while already driving on Glades Road or coming in from the I-95 ramp, their speed will likely be reduced, meaning that any possible crashes will have reduced severity.

DDI’s have “somewhat of a traffic-calming effect,” Martinez said, adding: “If someone is driving at 60 mph, we’ll have a totally different experience than someone crashing at 25 mph.”

Now, Martinez noted that if someone decides to drive recklessly through a DDI, FDOT has installed extra safety measures to curb potential harm.

If someone somehow misses the many “wrong way” and “do not enter” signs and begins driving the opposite direction, FDOT’s wrong-way detection system will sense the vehicle, alert the driver they are going the wrong direction through flashing lights, and notify law enforcement, the Traffic Management Center and Florida Highway Patrol. The agencies will then try to find the driver and stop them before they crash into anything.

A “formal evaluation” has not yet been conducted to determine if crashes have been reduced at the Glades Road DDI, but a DDI in Jacksonville along I-95, which opened in 2020, has seen a reduction from 5.4 annual crashes to 1.4.

For a lot of people, “this was the first time they had ever even seen something like this,” said Andrea Pacini, an FDOT spokesperson. “There was a learning curve, but then just like anything else, people drove it and they’re like, ‘Oh, this is faster, and it does work better.'”

Future diverging diamonds

Over the next several years, at least four new diverging diamond interchanges are scheduled for Palm Beach County. DDI’s typically have three phases: planning, development and environmental, design, and construction, each of which takes a couple of years to complete with the whole process possibly taking up to a decade.

Here are the projects on tap in the county:

— DDI at Lantana Road is in the design phase, and construction is expected to begin in 2027.

— DDI at 10th Avenue North in Lake Worth Beach is in the design phase, and construction is expected to begin in 2030.

— DDI at Hypoluxo Road is in the design phase and is expected to begin construction in 2031.

— DDI at Linton Boulevard is in the planning phase and is expected to begin construction in 2031.

Drivers can still use these interchanges during construction, though FDOT has had to shut down intersections for entire weekends in the past, Pacini said.

Martinez said the Federal Highway Administration has been promoting these types of interchanges, which is why they have begun to take off in Florida in the last couple of years. Nearly 50 DDI’s are at some phase of the process across the state.

“The overall feedback has been positive, and people are realizing that it is safer, and it is faster,” Pacini said.