Review Begins Of Falling Concrete In Big Dig Tunnels

"The widespread trouble spots prompted the Turnpike Authority to order an inspection of the city's entire highway system -- even parts that are decades old and not part of the $14.6 billion Big Dig system, the nation's most expensive highway project.

In May, federal prosecutors brought the first criminal charges in the trouble-plagued Big Dig project against six men who worked for the project's largest concrete supplier, accusing them of falsifying records to hide the inferior quality of concrete.

...Commuters waited years for the Big Dig to bury the city's antiquated central artery and send traffic underneath downtown. But the accident has raised new questions about the project."