Traffic that crosses over Interstate 70 on Route 51 will switch to a new pattern beginning Tuesday morning, as PennDOT partially opens the new diverging diamond interchange under construction there in Rostraver.
Route 51 traffic will continue to flow in a single lane each northbound and southbound, but those lanes now will be farther apart.
Most recently, both lanes were at the eastern edge of twin side-by-side bridges over the interstate. On Tuesday, one of the lanes will be at the eastern edge of the bridges and the opposite lane will be at the western edge, said PennDOT District 12 assistant construction engineer Dominec Caruso, who is overseeing the project.
Caruso said the traffic shift will allow crews to work on new median areas and islands that eventually will separate two lanes of Route 51 traffic in each direction, along with turning lanes.
The goal is to have all lanes of the diverging diamond open to traffic this year.
“We’ll get there as fast as we can,” Caruso said, noting progress will depend on weather conditions.
In the diverging diamond format, the northbound and southbound lanes cross over and swap positions at each end of the bridge. 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.
Those who are exiting I-70 likewise will be able to turn left from the exit ramp onto Route 51 without watching for opposing traffic.
Caruso said traffic flaggers and Rostraver police will be on hand Tuesday to help direct motorists during the transition in lane patterns.
The new diverging diamond interchange replaces a previous version that had a cloverleaf design. The construction is part of a $120.6 million project along the I-70 corridor.
Work is expected to continue into 2026 on improvements — including widening of the median and shoulders — on a section of the interstate adjacent to the revamped interchange.
Visit i-70projects.com/projects/I-70-at-sr-51-interchange for more information about the Rostraver project and navigating through the diverging diamond.
