Three people were killed and three others were seriously injured.
At about 1:30 a.m., on June 28, 1983, a 100-foot span of Interstate 95 in Greenwich collapsed into the Mianus River in one of the most infamous American bridge disasters of the 20th century.
A car and two tractor-trailers careened over the edge of I-95.
The death toll could have been significantly higher if the collapse occurred during rush hour, officials said.
Subsequent investigations found the immediate cause of the Mianus River Bridge collapse involved two corroded support pins.
However, years of deferred maintenance and systematic neglect were the true culprit, according to the Connecticut State Historian's office.
People were shocked to discover that the bridge was only 25 years old and had apparently passed a routine DOT inspection only nine months before. In the days leading up to the collapse, local residents who lived near the bridge complained about an ominous increase in strange noises and vibrations coming from the bridge, but no action was taken.
For months, tens of thousands of motorists who traveled I-95 daily had to be diverted onto Route 1 in Greenwich, clogging up local roads throughout the region as crews worked to get the bridge repaired.
In July 1983, the temporarily-repaired bridge was reopened to light vehicle traffic; buses and trucks would have to wait until full repairs were completed in September.
The Mianus River bridge collapse spurred drastic changes in how highway bridges were constructed; builders were thereafter required to incorporate multiple redundancies into their designs so that the failure of one single feature (a support pin) would not cause a collapse.
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