Mike Hellgren BALTIMORE COUNTY, Md. (WJZ)

The NTSB has revealed what caused the fatal Bay Bridge crash in 2008 that sent a tractor trailer plunging into the water below, killing the driver. Mike Hellgren has some revealing information from that report.

The NTSB says corrosion was a factor in that accident. However, it's the testing they recommend that's at the heart of this--they want testing that can see through the concrete and that visual inspections don't work.

The devastating accident on the Bay Bridge two years ago raised major concerns about the structural integrity of the barrier wall and sparked an NTSB investigation that was just released.

"We're very gratified to see that the NTSB put intense scrutiny into this issue," said Keith Franz.

Franz represents the family of John Short, who died in the tractor trailer crash.

Police say a Chevy Camaro crossed the center line and a big rig swerved to avoid it, broke through the barrier wall and plunged 30 feet into the water.

Inspections revealed the bolts connecting the barrier to the bridge were corroded, damage that couldn't be seen by visual inspection alone. Maryland used technology--ultrasonic and infrared scans and radar--that found 10% of the bolts were broken.

The new NTSB report recommended all states should use those high-tech inspection methods, that it's essential to determine whether bridges are safe.

"It's clear that they want all 50 states to now do effective testing of steel contained in the bridges, often which is not visible," Franz said.

The state spent millions to improve the barrier walls in the wake of the accident.

"The state has really gone out of its way to ensure the safety of the bridge and we believe they've done an effective job," Franz said.

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