The concrete slab that fell from the ceiling inside a tunnel section of Boston's Big Dig, killing one person and injuring another on July 10, raised a hue and cry throughout Boston about the massive, $14 billion, multiyear construction project.
The accident closed a major artery and caused a ripple effect of traffic congestion that was still disrupting commuters the next day.
But, according to MIT Professor Joseph M. Sussman, a specialist in transportation systems and one of the original strategic planners of the U.S. Intelligent Transportation System, the late-night accident does not indicate the Big Dig itself has failed to deliver.
"The Big Dig is conceptually sound. It's a good system with dramatic potential. It has provided the Boston metro area with a more efficient traffic pattern. If it is coupled with the investments in public transportation that are on the agenda, we will have a better, more balanced transport system," said Sussman (Ph.D. 1968), the JR East Professor in the Department of Civil and Environmental Engineering and the Engineering Systems Division.
"This type of congestion is an opportunity for the public transportation system to shine. Who knows? Maybe people who never take the T will try it for the first time this week," he said.
A balanced system, Sussman noted, is one in which people can switch flexibly from one travel modality to another - from driving to taking the bus, for example - based on real-time information about traffic conditions.
Boston's current transport system is sometimes more a balancing act than a balanced system, Sussman admitted. When drivers seek alternate routes to travel around the area, congestion "propagates all over the system, an illustration of the relative fragility of the transportation network," he said.
Congestion thus occurred "quite far from the accident. People who usually take the Mass Pike switched to Route 2. Route 2 was congested, so some drivers switched to Trapelo Road and the city streets. The ripples go way beyond the highway system and even extend to the MBTA," he said.
Sussman sees progress, if not perfection, in this week's traffic jams: Unlike five or 10 years ago, drivers had access to accurate real-time information about traffic conditions from many sources, including the Internet.
Also, the tunnel accident, while awful, occurred late at night during the summer, resulting in less congestion than, say, during a winter rush hour.
Yet, as a specialist who has worked on transportation plans for some of the world's densest mega-cities, Sussman doesn't advocate either better luck or more roads to mitigate congestion.
"Efficient transportation systems and good environmental practice both require better public transit. If we're going to get people out of single-occupancy vehicles, we'll have to develop mass transit," he said.
Sussman has written two books on transportation, "Introduction to Transportation Systems," a graduate textbook, and "Perspectives on Intelligent Transportation Systems."