Motorists in Washington County will soon find themselves surrounded by innovation, ranging from a soon-to-be-completed network of traffic cameras and message signs to cutting-edge intersection and interchange designs.
A three-year, $10 million "intelligent transportation system" project that features 21 traffic cameras and eight variable message signs is 95 percent complete and is expected to debut later this year, said Robb Dean, traffic manager for District 12 of the Pennsylvania Department of Transportation.
Plans are moving ahead for a creative "double roundabout" at the misaligned intersection of Route 519, Thomas-Eighty Four Road and Brownlee Road in North Strabane, with construction expected to begin next year.
Several other roundabouts are being planned for interchanges along Interstate 70, which is being rebuilt in phases from the West Virginia line to New Stanton. The Bentleyville interchange, scheduled for reconstruction starting in 2015, will have one; as many as three are planned for the New Stanton interchange, also slated for reconstruction starting in 2015.
A roundabout is the modern version of the traffic circle. There are no signals, and traffic entering the roundabout must yield to vehicles already in it. Roundabouts have been shown to improve both traffic flow and safety.
Rachel Duda, assistant district executive for design, said roundabouts have reduced crashes by 37 percent, crashes with injuries by 75 percent and fatalities by 95 percent.
PennDOT also is planning the state's first "diverging diamond" intersection, where Route 19 meets I-70 in South Strabane. In a diverging diamond, both directions of traffic on a main road (in this case, Route 19) are crossed over to the left side on the approach to the highway. That allows left turns onto highway entrance ramps without crossing oncoming traffic. Right turns to entrance ramps are made before the crossover.
The first diverging diamond interchange in the U.S. debuted in Springfield, Mo., in June 2009 and has met with overwhelming public support as it reduced crashes and improved traffic flow. Con- struction also is cheaper: Penn- DOT expects to save $4 million to $5 million over a conventional interchange reconstruction, Ms. Duda said.
Although shifting traffic to the left seems radical, the plans have been "really widely accepted" when shown in public, she said. Construction, which includes widening and rebuilding I-70 from Route 136-Beau Street to the north junction of I-79, is scheduled to start in 2015.
The traffic camera and signage network will be connected to the already extensive system that is operational in District 11, which includes Allegheny County, Mr. Dean said. The idea is to alert motorists of incidents before they get stuck in traffic.
Sixty-five miles of fiber optic cable has been lain and wireless antennae, some towering to 80 feet, have been erected. Sixteen of the 21 cameras will be along I-70 in Washington and Westmoreland counties, with eight in the congested stretch that includes the north and south I-79 exits.
In other matters addressed at a public briefing last week:
• Work on the $35 million reconfiguration of the south junction of I-79 and I-70 is "going really smoothly," said Scott Faieta, assistant construction engineer. Piers and beams have been erected for the new flyover ramp from northbound I-79 to westbound I-70.
The project, which eliminates the notorious loop with the rumble strips and high concrete wall that has weathered countless crashes, is expected to be completed in fall 2014.
• All ramps are open at the expanded I-79 Meadow Lands interchange. Work on a box culvert on Manifold Road may be completed by June, wrapping up a project that was delayed nearly a year by problems with utility line relocation. It added a southbound exit ramp from I-79 to Manifold Road, Locust Avenue and Pike Street and an on-ramp from those roads to the northbound side of the highway, completing the half-built interchange.
• The new $26 million Charleroi-Monessen Bridge over the Monongahela River is expected to open June 29, said Bill Kovach, assistant district executive for construction. The old bridge was closed in February 2009 after an inspection showed serious deterioration.
• A long-delayed project to reconfigure the Route 19-Valley Brook Road intersection in Peters will start in May. The $4.9 million project will realign and lengthen the ramp from Valley Brook Road to northbound Route 19. Valley Brook will have detours during the work, which is expected to span two construction seasons.
• Work will begin next month on repairs to southbound I-79 from Canonsburg to Houston, one of the roughest stretches of interstate in Western Pennsylvania. Completion is expected in August.
• Eight more I-70 projects, costing an estimated $430 million, are scheduled for construction starts in 2014-16. "This interstate was built over 60 years ago," district executive Joseph Szczur said. "It's seen its useful life."