A plan to add variable tolls to part of Florida’s Turnpike — already a toll road — was put into a higher gear on Thursday.

With a 12-1 vote, Miami-Dade commissioners, mayors and other elected county officials who belong to the Miami-Dade Metropolitan Planning Organization endorsed a plan to add variable toll express lanes to segments of the Homestead Extension of Florida’s Turnpike. The move clears the way for the Florida Department of Transportation to go forward with the plan.

Turnpike officials said that it will take at least five years before the first express lane is operational between Caribbean Boulevard and State Road 874, the Don Shula Expressway.

According to the plan, two more express lanes would eventually run northbound and southbound on the turnpike between Kendall Drive and State Road 836, perhaps by 2020; the lanes would be added at the same time that the expressway is widened, a project that may begin next year.

“What we are trying to do is to create good mobility for people who are looking for through trips and time reliability,” said Diane Gutierrez-Scaccetti, executive director and chief executive officer of Florida’s Turnpike Enterprise.

“There are commuters who are looking to make a direct trip that doesn’t involve a lot of the on-and-off traffic, that doesn’t involve the weaving and merging,” Gutierrez-Scaccetti said. “They just need to get on and they want that time-reliable trip. The express lanes are all about providing travelers a choice.”

But Miami-Dade Commissioner Bruno Barreiro, who was the only one to vote against the project, said the plan was unfair to commuters.

“They are taking away a regular lane from the commuters,” Barreiro said. “It’s a toll within a toll and I don’t like that concept. It takes from the regular commuters who are already paying a toll. It’s like double taxation.”

Turnpike officials responded that they would not be taking regular lanes, but instead adding express lanes to a widened road.

“There will be what we refer to now as new general toll lane capacity, but we will convert one lane to an express lane,” Gutierrez-Scaccetti, referring to the single express lane from Caribbean Boulevard to 874. “There will be a break for about two miles, so that folks can access our service area, and then just north of the service area it will pick up again at Kendall Drive and it will go to 836, but that will be two express lanes.”

Turnpike officials at the meeting also noted that drivers’ speeds generally increase and driving conditions generally improve on all lanes as a result of express lanes, which have become widely used on Interstate 95 in Miami-Dade since 2008. They are now being extended into Broward County. They are also being planned for Interstate 75 and the Palmetto Expressway.

Drivers who use these lanes agree to pay a toll that increases as more vehicles enter the express lanes. In Miami-Dade, prices start at 25 cents and have gone up as high as $7.10, which rarely happens. Drivers on regular I-95 lanes do not pay a toll.

But the concept of adding express lanes on the turnpike is different because tolls are already charged on that highway. This means drivers who use turnpike express lanes will agree to pay a higher toll depending on congestion on the express lanes, while tolls on the regular lanes will remain fixed regardless of traffic conditions.

The Caribbean Boulevard-874 segment may go into operation in 2017 while the Kendall Drive-836 leg may open three years after that, said Gutierrez-Scaccetti.

The Homestead extension recently went cashless, with tolls being collected by SunPass or by bills mailed to drivers who do not have transponders in their vehicles, a system known as Toll-by-Plate. Express lanes will be SunPass only, like the I-95 express lanes.

Fixed tolls on the Homestead extension are now $1 with SunPass and $1.25 with Toll-by-Plate at the four mainline tolling locations: Homestead, Bird Road, Okeechobee Road and Miramar.

Officials said they still do not have specifics on the price range for variable tolls on future express lanes, but Gutierrez-Scaccetti indicated that the starting rate may be 25 cents above the SunPass rate.