An innovative reversible-lane elevated toll road is beginning to take shape in Hillsborough County, Fla. The three-lane, precast concrete elevated portion is being built on piers within the median of the Lee Roy Selmon Crosstown Expressway. When completed in 2005, it will provide added capacity to the direction most traveled by morning and evening commuter traffic and double as a research project for intelligent highway systems.

"Most [expressway] traffic is commuter traffic," says Patrick McCue, executive director of the Tampa-Hillsborough County Expressway Authority. "So there is a need for more capacity at certain times of the day." The $350-million project will help alleviate congestion for 75,000 daily commuters on the nine-mile stretch between downtown Tampa and Interstate 75 near Brandon, Fla.

REVERSIBLE New elevated road will test highway technologies. (Photo courtesy of Figg Engineering Group)

PCL Civil Constructors Inc., a division of Edmonton-based PCL Enterprises, has a $145-million contract to construct most of the elevated six-mile portion leading to downtown as well as a section passing over I-75. Orlando-based Hubbard Construction will construct the at-grade three-mile portion and several feeder roads. David Dempsey, vice president of Hubbard Construction's Tampa division, says its work is 15% complete, including 35,000 ft of barrier wall.

"This will be the most technologically sound stretch in the world," McCue says, noting that up to $20 million is spent for information technology. Hollow cores of the precast segments allow for placement of sensors for intelligent highway systems.

"The importance of having such automation lies in driver safety and the increased [road] capacity–finding the right mix between what can be put in the roadway and what can be put in the vehicle," he says. McCue says other cities are evaluating the project.

"This is the answer for the future of urban transportation," says Linda Figg, president of Tallahassee-based Figg Engineering Group, the designer. No rights-of-way had to be obtained and existing traffic is not interrupted, she adds. The piers use just 6 ft of the expressway's 40-ft median, "so there's room to expand the expressway in the future."

The viaduct's precast segments weigh 90 tons each. Segments will be precast at the Port of Tampa and delivered to the site. PCL now is drilling shafts to 70-ft depths and has poured some of the supporting piers.