David Gwynn remembers the skepticism that greeted the highway interchange design known as a diverging diamond.“Everybody thought this was going to be a disaster,’’ said Gwynn, district secretary for the state Department of Transportation.The state rolled out the finished product in 2017 at Interstate 75 and University Parkway near Sarasota. Exit 213 requires motorists traveling east and west to cross over temporarily into the lanes on the left side of the road. Doing so substantially reduces traffic-signal wait times for drivers seeking to make left-hand turns, allowing more vehicles to access the highways during green lights.The public’s safety fears about driving on the other side of the road turned out to be unfounded. The Transportation Department reported no increase in crashes during the first year the new interchange operated.“Everybody figured it out pretty quickly,’’ said Gwynn. “It’s pretty intuitive.’’The need for intuition is about to come to Pasco County. Construction of the diverging diamond interchange at I-75 and State Road 56 is scheduled to begin this month, nearly six years earlier than originally projected.“I’m ready for it. I’m sure citizens are, too. We’re all ready for it,’’ said Pasco County Commissioner Mike Moore, who confronts the SR 56 traffic daily when he leaves his Wesley Chapel neighborhood.Relief, however, won’t be immediate. Construction is expected to take up to three years.“If you don’t like growth, stay away from (SR) 56 and I-75 for the next 30 months,’’ said Pasco Commission Chairman Ron Oakley.D.A.B. Constructors is handling the job that carries a $33 million price tag. The project is intended to ease traffic congestion in the rapidly growing quadrant of southern Pasco where Lutz, Land O’ Lakes and Wesley Chapel meet.Over the past four years, development near the interchange has included the Tampa Premium Outlets mall, the Cypress Creek Town Center retail project, the Florida Hospital Center Ice complex and two hotels.The state opened the interchange and a portion of SR 56, between Wesley Chapel and Bruce B. Downs boulevards, in 2002. It provides access to the nearby residential and commercial growth, and serves as the east-west highway for motorists driving between I-75 and the Veterans Expressway entrance at North Dale Mabry Highway. Likewise, it provides a link to the SR 54 interchange with the Suncoast Parkway in Lutz/Land O’ Lakes.State traffic counts for 2017 show 73,000 vehicles travel SR 54 east of Livingston Avenue each day. Motorists heading to and from I-75 share the route with local traffic in Land O’ Lakes. That makes it the busiest stretch of highway in Pasco County aside from the interstate.Traffic routinely backs up as commuters wait to enter I-75 and head south toward Tampa each morning, and again in late afternoons as traffic backs up on the SR 56 exit ramp.East-west highway improvements will aid developmentWhile crews begin rebuilding the interchange, others will be working nearby on SR 56 — extending the multi-lane highway nearly seven miles eastward from Meadow Pointe Boulevard to U.S. 301.Initially scheduled to conclude in late 2019, Gwynn said “there is a good chance it could be open as early as spring.’’When completed, the extension will provide Pasco with its first east-west multi-lane highway across the county, beginning as State Road 54 at U.S. 19 in west Pasco and traversing the county to U.S. 301 on the east side.The $59.1 million extension began two years ago. Originally. it was conceived as a two-lane route to be widened later. Then, Pasco County and the city of Zephyrhills tapped a state loan program to build all four lanes at once with the added costs to be repaid by surcharges on future development along the highway.“That’s going to open up so many opportunities,’’ said state Rep. Danny Burgess, R-Zephyrhills. “It’s going to be huge.’’The new highway extension will help stimulate already planned growth, including the Wyndfields development of nearly 2,000 homes and the massive Two Rivers project. Two Rivers is on 3,528 acres between Morris Bridge Road and U.S. 301, and proposes to include 6,400 homes and apartments, 2.7 million square feet of office space and industrial use, plus 630,000 square feet of retail stores.Zephyrhills officials lobbied for the four-lane extension, saying it was key to economic development in the county's southeastern corridor. The city's airport and industrial park are northeast of where the new road intersects U.S. 301."The access in and out of here is just dismal,'' Zephyrhills City Manager Steve Spina said when Burgess announced the state loan nearly four years ago. "Everything is two lanes or funnels into two lanes. Access here is vital, and (the SR 56 extension) will open up a lot of this area to economic development, to jobs, to a better tax base.''But SR 56 won’t be the only east-west highway improvement in Pasco.By June, the state expects to seek bids on $150 million worth of projects on State Road 52. They include widening it to four lanes between the Suncoast Parkway and the U.S. 41 intersection, and realigning the highway in east Pasco from Uradco Place east of I-75 to Fort King Road.The realignment will take the highway south of the towns of San Antonio and St. Leo, and travel through the Mirada development (formerly the Cannon Ranch) before connecting to the south side of Dade City where Clinton Avenue will become the new SR 52. The existing state highway, including the dog-leg in San Antonio, will become County Road 52 when construction is completed.That improved east-west network also is projected to be a boon to the vicinity. Just ask Dewey Mitchell whose company, Berkshire Hathaway Florida Properties Group, is marketing the space available at the Dade City Business Center.“It’s a game-changer for the Dade City area,’’ said Mitchell, “to have this kind of transportation.’’Contact C.T. Bowen at [email protected] or (813) 435-7306. Follow @CTBowen2.