NEW YORK (CBSNewYork) – A Connecticut woman testified Thursday in the manslaughter trial of a tour bus driver that Ophadell Williams’ driving made her and her husband nervous.

In day two of testimony, Sonia Barlow of Old Saybrook told the court she and her husband observed the World Wide Tours bus swerving and straddling lanes.

WCBS 880’s Irene Cornell reports

Williams pleaded not guilty to manslaughter and criminally negligent homicide in the March 12, 2011, crash after prosecutors said he was seriously sleep-deprived but drove anyway.

Barlow testified in Bronx Supreme Court that her husband honked his horn, nervous that Williams would swerve into their lane. Williams was driving erratically, first speeding by them then going so slowly they were forced to pass the bus, Barlow testified.

The wreck happened on Interstate 95 in the Bronx when the tour bus on its way to Chinatown from Mohegan Sun in Connecticut overturned and slammed into a pole. The impact of the crash peeled off the roof of the bus, killing 15 passengers and injuring 18 more.

In court Thursday, Barlow testified that she thought it was a party bus with a young driver under the influence behind the wheel.

Barlow told jurors she and her husband, who were driving to South Carolina, did not witness the crash but heard about it later on the news. It was not until the couple heard about the crash that Barlow said she called police.

Barlow told jurors she wanted to offer her account of what she saw after hearing that Williams claimed he was cut off by a tractor-trailer, causing the fatal crash.

The National Transportation Safety Board said in June that the accident was probably caused by driver fatigue and a bus company that provided too little safety oversight. It stopped short of saying Williams had fallen asleep.

Prosecutors say Williams had been driving recklessly and speeding nearly 30 miles over the limit.

Williams said that a tractor-trailer had cut him off and that’s why he swerved and hit the guard rail. But investigators could find no indication that had occurred.

The NTSB said Williams had almost no sleep in the days leading up the crash, saying he only took naps on the bus while passengers were gambling inside the Connecticut casino.

Investigators also found that the bus was traveling at speeds up to 78 mph in a 50 mph zone until seconds before it ran off the road.

The NTSB said the bus company, World Wide Tours, was also to blame for not providing sufficient safety oversight.

After a series of fatal bus crashes last year, federal officials began investigating the safety of curbside bus operators as a whole.

As a result, the U.S. Department of Transportation and the Federal Motor Carrier Safety Administration shut down 26 bus operations for multiple safety violations.

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