The new Tampa-Hillsborough County (Fla.) Expressway will be more than a road; the highway also will serve as a field laboratory for testing innovations in highway and vehicle safety and other technological advances. For nine miles, reversible elevated express lanes will be built within the median of the existing toll highway, and 5.4 miles of that stretch will consist of a reversible-lane bridge. "The reversible lane improvement will maximize the utility of existing transportation assets, preserve options for future expressway improvements and minimize the impact on the surrounding environment," says Ben Muns, chief engineer for the Tampa-Hillsborough County Expressway Authority.

The reversible express lanes will be constructed on the Lee Roy Selmon Crosstown Expressway to improve commuter service between the suburbs in eastern Hillsborough County and the employment centers in downtown Tampa. They will operate inbound from Brandon to the central business district during the morning rush hour and in the opposite direction in the afternoon.

Designed for cars and buses only, the express lanes will incorporate a number of advanced features for driver information, traffic control and safety:

- dynamic message signing to instruct motorists of the status of the express lanes;

- special signals, controls and "gates" to ensure that motorists do not enter the system traveling in the wrong direction;

- electronic toll collection and video surveillance, allowing motorists to travel without interruption; and

- computer-synchronized traffic signals on the connecting roads in Brandon and Tampa that will prevent backups at each end of the expressway.

For most of their length, the lanes will be elevated on a concrete bridge above the existing four-lane expressway. Bridge segments will be pre-fabricated off-site, delivered to the expressway and erected in the median of the existing roadway. The bridge piers will be located between the existing expressway lanes.

Construction of the bridge is expected to begin by the end of 2000; it is scheduled for completion by 2005 at an estimated cost of $190 million for the reversible lanes and $60 million for the arterial feeder roads. The project will be financed by a $1 toll paid by motorists.

San Francisco-based URS, the general engineering consultant to the Expressway Authority, is responsible for completing traffic and revenue analysis, planning and feasibility studies, conceptual design, environmental impact assessment and preliminary construction plans. The company also will oversee the design of all connecting ramps, retaining walls, signage, lighting, and aesthetic and landscaping enhancements.