Boston's Expensive Traffic Snafu

Some serious new problems have piled up in Boston for the Big Dig, which is now on track to cost nearly $2 billion a mile, making it the most expensive highway project this country has ever seen.

The Big Dig has long been the butt of jokes about incompetence and cost overruns. But those jokes aren't funny anymore, not after the death on Monday of a woman who was crushed when 15 tons of concrete fell from a tunnel ceiling onto her car.

Since then, at what is now a crime scene, investigators have found 362 potential defects.

"The history of this project is just one that makes you shake your head," said Gov. Mitt Romney.

Seven years after the project began, in 1991, costs jumped from $2.6 billion to $10.8 billion. Then in 2004, a leak flooded one of the tunnels, causing massive traffic jams.

The problems continued last year when investigators found 169 defective areas along the Big Dig. In May, six men were charged with trying to hide the inferior quality of some of the concrete used on the highway.

Despite all those setbacks, the death of 38-year-old Milena del Valle shocked even those who'd become fed up long ago.

One woman told ABC News, "It's scary. You never know what you're going to get into."

Federal and state investigators are now trying to decide where to place blame for del Valle's death. After 15 years and $14.6 billion spent, much of the Big Dig is closed, and no one knows when will it be safe to open it again.