The Route 301 bypass opened on Thursday.
The new route will run from the Maryland line to an interchange with Route 1.
The $636 million superhighway was divided into seven construction contracts that were issued at the same time.
The contracts were issued separately since few firms would have been able to handle the project and bids might have been scarce and high, DelDOT indicated.
The toll road addresses a traffic choke point that has grown worse over the years.
While Maryland made 301 into a four-lane highway decades ago, a variety of factors including squabbles over the route, led to Delaware to keep two lanes.
The Marylandside of Route 301 has its own challenges, with at-grade intersections, rather than cloverleaf exits. The intersections pose dangers to motorists. The speed limit has remained at 55 miles an hour.
The growth of Middletown made things worse as a growing number of large trucks and overall traffic in the car-centered town began choking traffic in the area.
The 14 mile-long US 301 bypasses 29 at-grade intersections, 18 of which are signalized, and numerous driveways with direct access to existing US 301. The existing US 301 will be converted to a local roadway, with truck restrictions in place except for local services.
“Opening the new US 301 to traffic is an important milestone in what has been a decades-long effort to address the safety and congestion issues created by the existing roadway,” said Gov. John Carney.“This new road will only enhance our economic development efforts for businesses that are looking to grow and move their goods around Delaware and beyond as efficiently possible.”
“I would like to thank our contractors and subcontractors who worked through one of the wettest construction seasons on record to move this project forward, and it is impressive that less than three years after groundbreaking we are now putting traffic on the new US 301,” said Secretary of Transportation Jennifer Cohan. “Work will continue to complete the entire project in 2019, and we look forward to having a formal opening event to celebrate this project.”
Ground was broken for the US 301 project in February 2016. The project is partially funded by a $211 million U.S. Department of Transportation loan that will be paid back through toll collections on the highway.