PennDOT on Tuesday completed work to fully open a new “diverging diamond” interchange at the junction of Interstate 70 and Route 51 in Rostraver.

The newly formatted interchange and nearby improvements on the two roadways have been under construction for three years.

The I-70/51 diamond configuration has replaced a previous cloverleaf interchange.

The northbound and southbound lanes of Route 51 now cross over and swap positions at each end of a bridge that carries Route 51 above the interstate.

That allows motorists who are turning left from Route 51 onto I-70 to do so without having to complete the move in front of oncoming traffic.

PennDOT officials reported shortly after 5 p.m. Tuesday, when the sun was setting, that two lanes of traffic were open on Route 51 in each direction through the interchange.

Commenting on the timing of that traffic change, PennDOT District 12 spokesman Andrew Stacy noted drivers already have been navigating through the diamond pattern. One lane opened in each direction in July.

Stacy said opening an additional lane in each direction should increase the interchange’s capacity and efficiency. With the busy Thanksgiving travel period coming up, he said, “It seems like a great time to open it.”

The interchange work is part of a $120.6 million improvement project on an adjacent segment of the interstate in Rostraver.

PennDOT completed Pennsylvania’s first diverging diamond interchange in August 2017 — farther west along I-70, where the interstate crosses over Route 19 in South Strabane, Washington County.

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