Love it or hate it, this much is certain: Tampa Bay Express will radically change a regional system connecting about 3.8 million people.

Here's a heads-up about when it's coming, where it's going, and how much it's going to cost.

A heavy toll: Here's how Tampa Bay's $6B highway expansion will burden minorities

What exactly is it?

Tampa Bay Express, otherwise known as TBX, is a $6 billion interstate expansion that has three main features, according to the Florida Department of Transportation's 172-page draft of the project.

The state wants to replace the three-mile span of the northbound Howard Frankland Bridge that opened in 1960. Bridges typically last about 50 years.

Also, transportation officials plan to rebuild the exchange between Interstate 275 and Interstate 4 near downtown Tampa. A state study shows "malfunction junction" was built to handle about 176,000 vehicles per day, but traffic is about 8.5 percent higher than that now and 53.4 percent higher by 2040, according to projections.

The third element is the most controversial: 90 miles of tolled "express lanes."

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How much do these toll lanes cost to use?

Unlike other tolls in the area, the express lanes will have a "variable" rate. This means the price goes up or down depending on traffic. The more traffic, the higher the toll.

FDOT wouldn't give the Times an estimate but the master plan says it could range from 15 cents to $2 per mile. Different road segments could cost different amounts, but at peak times it could cost $30 to cross the Howard Frankland and get to downtown Tampa.

High tolls are meant to discourage drivers from using the lanes and slowing down traffic. Toll rates will keep rising, experts say, because the state wants to provide a minimum speed of 45 mph in the pay lanes. To do that, the express lanes can't get clogged by too many drivers.

Who's paying for it?

Money for a majority of the construction comes out of the state's Strategic Intermodal System — a fund consisting of state and federal gas tax dollars that pay for a network of high-priority projects. The remaining 14 percent is covered by FDOT's district dollars and the Florida Turnpike Enterprise. The operation and maintenance of the project — once built — will be paid for by drivers who use it, said Debbie Hunt, an FDOT district 7 director of transportation development.

Where can I get on and off these lanes?

There are 33 exits along the 50-mile stretch of I-275 and I-4 where the first phase of TBX will go.

The express lanes will have only 10 access points in this same span.

Express lanes limit the number of entrances and exits to keep traffic flowing smoothly. When vehicles merge on the interstate, traffic naturally slows down.

Why does it matter where motorists can access TBX?

The project is picking winners and losers.

State planners acknowledge picking access points based on important hubs, like Tampa International Airport, the Gateway area of Pinellas, the Westshore business district and the University of South Florida. TBX funnels traffic to these destinations.

But the express lanes bypass other locales.

For instance, the lanes are difficult to access for at least 20,000 people who live in Central Tampa and other neighborhoods near the downtown interchange. Along a three-mile stretch that runs through their communities, there is a single exit compared to five currently for the regular lanes.

When will construction begin?

Construction will start next year in Pinellas Park and the Gateway, followed by the Howard Frankland in 2019. The final part, near Westshore and TIA, is slated to start in 2023. Construction for the initial phase is expected to finish by 2026.

The other segments of the master plan, which include Interstate 75 and connections to Polk and Pasco counties, are not currently funded and won't start until after the first phase is completed.

What about more buses or rail?

The plan preserves space for express bus or rail along I-275 from Westshore to downtown Tampa to Plant City and beyond. But that transit corridor only runs east-west. It does not continue north along I-275 up to the University of South Florida. As of now, Hunt said, the plan only indicates two stops: one at a transit hub at Westshore and another in downtown Tampa.

While cars will pay to use the toll lanes, public school buses and express buses will be allowed to travel in them without paying the toll, providing another option for commuters. This concept is still in early planning stages. Routes have not be been designed yet. It's unclear what money would pay for this or how buses can use the lanes without slowing traffic.

Do local officials have to approve the project?

Unlike recent attempts to fund transit, the public doesn't get to vote on TBX. But a group of elected officials called the Hillsborough Metropolitan Planning Organization will decide on June 22 whether to include the project in its yearly Transportation Improvement Plan.

If a majority of MPO members vote yes, FDOT will start construction next year.

But if the MPO decides to remove TBX from its priorities, that state money is likely to go somewhere else in Florida, FDOT officials said, such as to Orlando or Jacksonville for projects similar to TBX.

Times senior news researcher John Martin contributed to this report. Contact Caitlin Johnston at cjohnston@tampabay.com and Anthony Cormier at acormier@tampabay.com.