PHOTO: I-95 Express Lanes

Traffic in the express lanes on I-95 in South Florida does not always move faster. (Carey Wagner)

Think you'll go faster on I-95 by paying $10.50 at rush hour to use the express lanes?

Think again. Sometimes, you will actually go slower than those in the free lanes.

Tolls are set based on how much traffic is in the express lanes – not the free lanes. The idea is to thin traffic in the toll lanes to keep traffic there moving at 45 mph or higher during rush hour.

To hit that goal, the state on March 1 increased tolls so they now range from 50 cents to $10.50 to drive seven miles between downtown Miami and the Golden Glades interchange.

Commuter Ed Halvorssen, of Aventura, said he was upset when twice this month he saw the results of paying the maximum firsthand.

"On both occasions I had to take the express lane, the normal lanes on I-95 were traveling at the same -- sometimes even faster -- speed than the express," he said. "Paying $10.50 to be able to drive on a 7-mile stretch of road, I expect to be able to zip by in next to no time."

The problem of slower express lanes so far is unique to I-95, which carries about 80,000 to 100,000 more vehicles a day than I-595, where reversible express lanes opened March 26.

In the spring of 2015, the I-95 express lanes will extend north to Broward Boulevard, with lanes coming to Delray Beach after 2019.

Officials concede they don't know how to get drivers to understand that higher tolls don't guarantee you will always be faster, especially at rush hour. They insist they have made it clear from the beginning that rates are based on traffic in the express lanes.

The rates are set based on overhead sensors, which detect the number of vehicles, how fast they are going and how close together they are. By raising the rate based on use, officials are trying to discourage those who don't need to drive at rush hour .

Steve Sternberg, of Boynton Beach, said that is an unrealistic goal.

"People driving to work, the majority at rush hour, generally have no choice to change times," he said.

Drivers paid the top toll rate of $10.50 on 16 days between March 1 and June 9. The average tolls paid during rush hour were $3.12 northbound and $2.46 southbound.

The higher toll rates appear to be helping the state achieve its 45 mph target -- but barely. In the northbound express lanes, speeds reached that rate 90 percent of the time in March vs. 83 percent the previous March.

Traffic volumes in the express lanes dropped about seven percent northbound and five percent southbound.

"The reliable trip is one of our biggest goals," said Alicia Torrez, spokeswoman for the Florida Department of Transportation.

mturnbell@tribune.com, 954-356-4155, Twitter @MikeTurnpike, Facebook at SunSentinel.com/concreteideas