To the northeast of Baltimore, where Interstate 95 meets the Beltway amid a forest of construction cranes, something truly mind-boggling is taking shape.
Here, the Maryland Transportation Authority is building a highway interchange to replace the 1960s-vintage connection between the two busy highways, where congestion has turned peak travel times into a commuter's nightmare.
This is no ordinary interchange. Designed to accommodate new express toll lanes in both directions on I-95, the junction will be an intricate "spaghetti bowl" of lanes, ramps and soaring flyovers.
Motorists can expect delays during construction, but when the interchange opens - in late 2011 if the project stays on schedule - it will be the largest structure of its kind in Maryland and perhaps the state's most significant highway engineering feat since the opening of the Fort McHenry Tunnel in 1985.
The interchange, with an estimated cost of $450 million to $500 million, will include 16 ramps carrying high volumes of high-speed travel on four levels to connect I-95's separate express toll and general-purpose lanes with the Baltimore Beltway.
Project manager Dave Greenwood said that in effect, the authority is building two new interchanges atop an existing one, while keeping the current lanes open to traffic.
Tom Warne, a former president of the American Association of State Highway and Transportation Officials, said after viewing a rendering of the project that it rivals the complexity of some of the large interchanges in Southern California, including one in Orange County known as "Orange Crush."
"This is going to put [Maryland] way at the top of complicated interchanges," said Warne, a former Utah transportation chief who runs a consulting firm.
Travelers in the I-95 corridor can see the project beginning to take shape in the form of tall T-shaped piers of steel-reinforced concrete rising to the sky. The piers, which will support 11 flyover ramps, soar as high as 80 feet and catch the eye of rubbernecking motorists.
"Certainly, the construction is impacting the driving habits," Greenwood said. "You can't help but watch what's going on."
But nothing drivers are seeing now can convey a sense of what is to come nearly as well as the renderings being displayed by transportation authority officials at public meetings and a recent media briefing. The drawings show a tangle of loops and whorls connecting the two highways, both of which are to be widened to relieve the corridor's persistent congestion.
