DADE CITY — The state Department of Transportation is taking a new route to building the next highway interchange in Pasco County — all in.
By doing so, it could avoid a repeat of the traffic snarls at the State Road 56 interchange at Interstate 75.
The SR 56 interchange, conceived in the 1980s, opened to traffic in 2002. It helped transform former pastures into an exploding corridor of malls, restaurants, offices, a hospital, ice skating complex, apartments and neighborhoods filled with high-end homes.
It’s not the growth that the state wants to skirt. What road planners hope to dodge is the remedial work required to help SR 56 and I-75 handle the heavy volumes of traffic.
Ten years after the interchange opened, the state spent $31 million to extend the northbound exit ramp more than 2 miles. Then it spent $3 million to lengthen the entrance ramp and add another left-hand turn lane. Now the state is retrofitting the interchange into a divergent diamond design — one that carries a $33 million construction price tag — intended to unclog the bottleneck where Wesley Chapel, Lutz and Land O’ Lakes come together.
The remediation wasn’t unexpected, it just came sooner than planned. Interchanges usually have a 20-year lifespan before improvements are needed, the state has said.
So, as it plans its newest I-75 interchange at Overpass Road, the state is going full speed ahead from the outset.
“We’re trying to get the ultimate interchange built so we don’t ever have to come back through there,’’ said Richard Moss, the Department of Transportation regional director of transportation development.
In this instance, “ultimate’’ means a flyover to make it easier for southbound traffic to enter the interstate. It will be similar to the I-75 interchange at Bruce B. Downs Boulevard in New Tampa and be the first flyover in Pasco County. Overpass Road sits nearly midway on the 6.6-mile stretch separating the existing interchanges at State Roads 54 and 52.
Initially, the state planned to build the Overpass Road flyover as a second phase at a future date, but “once you open up that interchange, it’s going to be real busy, and you don’t want to do a (second phase) construction project with that,’’ said Moss.
His comments came during an Aug. 8 briefing before the Pasco Metropolitan Planning Organization made up of elected county and municipal officials sitting as transportation planners. The plan drew praise from board members and later from the business community.
"We applaud the state for being proactive as to the future needs of this interchange. This will certainly be beneficial to commuters and locals alike,'' said Hope Allen, president and CEO of the North Tampa Chamber.
The state advertised on Aug. 12 for design-and-build teams to make their pitches for the work. The contract is scheduled to be awarded in April 2020, and construction could take an estimated 800 days. That means, if all goes according to plan, traffic could be using the interchange by fall 2022.
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The Federal Highway Administration approved the Overpass Road interchange in 2014. The estimated construction and right-of-way costs are listed at $63 million.
Pasco County is using Penny for Pasco sales tax dollars, transportation fees from developers and property taxes for its $33 million share. The state allocated an additional $15 million in its 2018-19 budget.
The project will include demolition of the existing bridge carrying Overpass Road over I-75 and widening about a mile of the road, from two to four lanes, between Old Pasco and Boyette roads.
The state also looked at a divergent diamond design for the interchange at Overpass Road, but decided against it. The divergent diamond includes shifting traffic patterns from the right-hand side of the road to the left, to eliminate wait times for commuters turning left onto the interstate’s entrance ramps.
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“That would help,’’ Moss said, “but in the ultimate, that flyover would process a lot more traffic going southbound. It’s a much better design.’’
The new interchange is a key element to handing an influx of traffic from both the connected city corridor and Pasadena Hills planning districts. Metro Development already is developing its Epperson and Mirada developments in the connected city that is projected to contain 96,000 people in 37,000 homes over the next 50 years. Pasadena Hills to the east is planned to have more than 40,000 homes.