The Pennsylvania Department of Transportation (PennDOT) has announced the completion of the state's first-ever diverging diamond interchange (DDI), located on Interstate 70, according to Equipment World.
The DDI design eliminates left turns across oncoming traffic, improving vehicle flow and decreasing the chance of accidents.
The agency also chose the DDI configuration because it could use the former interchange's cloverleaf footprint, reducing the impact of construction on the area. PennDOT said it modified the traditional DDI design slightly.
Design is one way transportation agencies are combating gridlock resulting from increased traffic. Other tools in DOT arsenals are the expansion of the highways themselves and variable tolling policies to decrease congestion in high-travel areas.
Earlier this month, Virginia officials broke ground on a $500 million extension of Interstate 395 express lanes along an 8-mile stretch from Alexandria, VA, to the Washington, DC, border. The project is part of a $1.4 billion state program to improve travel between DC and Fredericksburg, VA. Elsewhere in the region, Interstate 270 in Maryland is gearing up for a $230 million overhaul in an effort to ease congestion on the corridor that connects with the Capital Beltway.
Using tolling or other fee-based systems as a strategy to thin rush hour traffic volume has also again become part of the discussion in New York City, as well as other metros where congestion causes lengthy commutes.
Gov. Andrew Cuomo has suggested using congestion pricing to reduce traffic flow through New York City, in this case by charging a premium to drive in and out of Manhattan during peak travel times. He's expected to announce specifics in January as part of his annual State of the State address. Previous plans for congestion pricing in New York City have failed, but Cuomo said the extra money could be used for city infrastructure upgrades, particularly throughout its aging subway system. New York City Mayor Bill de Blasio has said he opposes the idea.
Lee County, FL, has had success with one aspect of congestion pricing, and that is discounts for tolls at slower times as way to reduce traffic during peak periods. In the late 1990s, Lee County began offering 50% toll discounts to drivers who traveled during set periods before and after rush hour. The strategy has reduced traffic during peak travel times by up to 20%, according to the FHA.