FDOT first identified a need to redo the span in 1992, when an analysis found numerous design, safety and capacity flaws. But the federal highway administration halted FDOT’s study for a replacement in 1996 because the agency’s approach — to replace the roadway with a similar functional design — did nothing to remedy the social and urban-design issues associated with the original.

Advocates and the Diaz administration first pushed for a tunnel or a new 395 sunk below street level to re-connect downtown with Overtown and the Omni districts. When that proved unfeasible for financial and engineering reasons, they agreed to FDOT’s idea for a distinctive, super-elevated span.

That scheme would also allow some blocked avenues to the west of Biscayne Boulevard to be reopened while freeing up substantial amounts of land for creation of parks, pedestrian connections and even new development.

The existing I-395 would be demolished entirely and a new highway, higher off the ground than the present version and with fewer support elements to obstruct through streets at ground level, would be built just to its north.

Both the Wishbone Arch and the segmental box versions would include those improvements, Pego said. The principal difference would be the type of bridge at the eastern end of the highway over Biscayne Boulevard flanking the Arsht. The roadbed of the new Boulevard bridge would be 25 feet high at its tallest point, some 10 feet higher than the existing span.

FDOT created an advisory group, which included business leaders, Overtown residents, city planners and Arsht Center representatives, to help select a design and a plan for adequate traffic circulation on surrounding streets. The agency held more than 75 community meetings to hammer out a broad consensus. Its engineering-design consultants, internationally known T.Y. Lin, developed 15 “signature” bridge designs, which the committee narrowed down to three.

On Jan. 23, the group picked the Wishbone Arch design. When the consultants, who said they were acting on FDOT’s instructions, then also presented two segmental box options, one topped with a “Lotus Flower” decorative sculptural element, the committee unanimously rejected both.

What’s unclear is what comes next. FDOT in the past has said 395 would not be replaced until 2020 at the earliest. Typically, once FDOT has settled on a design, it puts a project on a 10-year list in line for funding.

But substantial new development in the area, plus still undefined plans by a Malaysian casino operator for a large resort on the site of The Miami Herald’s building, have generated pressure to speed up the roadway’s replacement.

Work is now underway on 395 to improve safety and traffic flow in preparation for the opening of the new PortMiami tunnel in 2014. FDOT has already started acquiring properties flanking the existing roadway.

Pego acknowledges the agency has no money to build anything right now, but argues that presenting a lower-cost alternative could help speed up replacement.

But if FDOT has no money for either version of the bridge, Diaz questioned why the agency would be pushing the segmental box bridge now.

“This is something for the next hundred years,’’ said Diaz, a member of the Arsht Center’s Town Square Development offshoot, which advocates for compatible development around the performing arts center . “And I think we deserve what we agreed to, what the community supported after innumerable public hearings. When you look at the spectacular potential of this district in the city, it’s just incredible.

“This is the picture that everyone will see of Miami. It should be something special.’’