The highway was called the "psychological and physical barrier" between the river and neighborhoods - a chief obstacle for more than 60,000 people who live within a short walk of the water.

Yet no one believed the road could be moved or even covered, given the multibillion-dollar tab.

So it's something of a pleasant whiplash moment to see that - just 18 months later - planners, civic leaders, and others are asking if the old pachyderm, I-95, can be tackled.

Inquirer architecture critic Inga Saffron detailed recently how the Big Dig road project in Boston - as well as San Francisco's Embarcadero boulevard - reconnected each city and its respective waterfront by transforming a major highway that sliced through town.

That's the aim of the plan developed in 2007 by the PennPraxis design group at the University of Pennsylvania, which drew on wide-ranging town-hall-style talks. It calls for new trails, promenades, businesses, homes, and, where possible, extending city streets to the river.

With I-95 as is, PennPraxis' vision can't be fully realized up and down the seven-mile stretch of the central Delaware.

So it's promising that city planning chief Alan Greenberger says he wants planners hired to draw up a new master plan for the central Delaware to confront the I-95 problem. That could be the fresh eyes needed to get past a long-held pessimism.

One thing's sure: Taming I-95 could be a game-changer in much the same way as the 1970s linking of the region's commuter rail lines in Center City or even the 1950s removal of the "Chinese Wall" rail viaduct that pierced the heart of downtown.

Until now, the only solution considered for I-95 was to cover its waterfront stretch. That still appears to be the best option, even though the staggering cost has put the project out of reach for decades. But President Obama's focus on infrastructure spending could well change the dynamic for financing such a project.

The new wild card in the I-95 debate is the idea that the downtown portions could be turned into a boulevard with crosswalks and traffic lights. Since most commuters exit for Center City, the slower portion of I-95 would be able to handle the volume. Or so the thinking goes. The plan requires far more study since it also might cripple through-traffic.

Mayor Nutter has embraced the idea of curing the I-95 headache, but that will happen only if he leads the fight by rallying residents, lawmakers, and businesses around a plan. Given the huge benefits for the city for decades to come, the mayor would have no greater legacy if successful.