Motorists will be confronted with an interchange unlike any other in Pennsylvania as the state Department of Transportation prepares to drastically alter Interstate 70 at the Murtland Avenue exit.
PennDOT is utilizing the bold and revolutionary “diverging diamond interchange” design at the crossroads of I-70/79, as it invests millions in an attempt to improve the outdated and dangerous ramps leading from Route 19 in South Strabane Township.
Construction on the diverging diamond, which was introduced in this country five years ago in Missouri and will be the first of its kind in Pennsylvania, is scheduled to begin in September and continue through 2017.
Barry Lyons, PennDOT’s District 12 senior project manager, said engineers considered many conventional designs to fix the often-congested ramps, but settled on the diverging diamond after learning of the new construction style.
Although it appears somewhat confusing when viewed from a map, he said it will make the interchange safer and cost less money to build than other potential designs.
“I think it’s a neat thing. We’re kind of proud of that,” Lyons said. “It took a leap of faith on our part to run with it because it’s something that’s different that we’re not used to, and that required risk.”
The design requires traffic to cross over and switch lanes, with traffic signals directing the flow to allow motorists passage through the area or onto the interstate going in either direction. That might be confusing to some at first, but motorists will figure it out quickly as they’re guided through their lanes, said Gilbert Chlewicki, a civil engineer living in Baltimore who pioneered the design a decade ago.
“It’s definitely going to be a great benefit for Washington,” Chlewicki said. “When you’re looking at it on a piece of paper, it looks very confusing. But when you’re driving through it, it’s very natural. It’s very easy to follow through from one side to the other and virtually impossible to make a mistake driving through.”
Chlewicki traveled across the country touting the design as a new way to relieve congestion and make interchanges safer. He spent Tuesday meeting with PennDOT engineers at their District 12 headquarters in Uniontown to discuss that and other traffic plans.
But while PennDOT and traffic experts are pleased with the design, it raised eyebrows among motorists and local police agencies. An open house will be held from 5 to 7 p.m. Thursday to display the project plans at South Strabane Fire Station No. 2, 172 Oak Spring Road. PennDOT officials hope such discussions will help alleviate concerns.
South Strabane police Chief Donald Zofchak said he’s withholding judgment on the interchange until after construction of the $57 million project is completed in three years.
“I’m like everyone else. None of us has ever seen something like this,” Zofchak said. “They say the concept works, and there are quite a few around the country. I have some concerns on that crossover and how it will take some time to get used to.”
However, he acknowledged that the current interchange at Murtland Avenue is dangerous and needed to be changed.
“The interchange the way it is right now is a safety hazard, so I can see PennDOT’s reasoning for doing something progressive,” Zofchak said.
His biggest concern is that a power outage in the area could cause traffic signals to malfunction at the crossover areas. He’s requested there be battery backups to make sure the intersections remain safe.
Others have concerns the additions of two more traffic lights on Route 19 will add to congestion or create more backups near the intersections with Trinity Point and Strabane Square.
Chlewicki dismissed those congestion concerns and thinks the timed lights will improve traffic flow in that area.
“You’ll probably see that it will be so efficient, it will probably work traffic through even easier,” Chlewicki said.
There are currently 34 diverging diamond interchanges in the country since the first was constructed in Missouri. Each was met with skepticism, Lyons said, only to later be embraced by motorists.
He said PennDOT has done its homework on the design and is excited about eventually showcasing the newfangled Murtland Avenue exit around the state.
“It wasn’t something where a light bulb just went off,” Lyons said about the decision to use the design here. “It’s something that evolved after a lot of research.”
Route 19 will remain open to traffic during construction as that stretch is reconfigured and the cloverleaf ramps are replaced.