New York (CNN) -- Sen. Charles Schumer is proposing to audit all New York bus drivers' licenses following last week's bus crash that killed 15.
Speaking in Chinatown Sunday, Schumer, a New York Democrat, asked New York state's Department of Motor Vehicles to re-examine all drivers of low-cost tour buses for previous safety violations and suspended licenses. He believes if an audit had previously been in place, the March 13 crash would not have occurred.
"The audit would have shown that the man behind the wheel shouldn't have been behind the wheel, and he wouldn't have been driving," Schumer said.
On Friday, 14 of 14 buses that were inspected by state Department of Transportation officials in Manhattan yielded violations -- either vehicle violations, which took the buses out of service, or driver violations or both, said agency spokeswoman Deborah Sturm Rausch.
The nine driver violations could include anything from a driver with an out-of-date license to one who had logged too many hours on the road, Rausch said.
On Thursday, random roadside inspections of 36 commercial buses by troopers resulted in 10 drivers being removed from their bus by the company and eight traffic tickets issued. None of the vehicles inspected were found inoperable, according to the New York State Department of Transportation.
"What's been uncovered thus far may very well be just the tip of the iceberg," Schumer said Sunday.
New York Governor Andrew Cuomo ordered an investigation last week into how the driver in the crash, Ophadell Williams, got a commercial license despite having a poor driving record and previous convictions of grand larceny and manslaughter.
Records on the Federal Motor Carrier Safety Administration website show that the bus line involved -- World Wide Travel -- was involved in a crash in New York in 2009 that resulted in one injury and a crash in New Jersey in 2010 resulting in another.
The company has been cited five times for "fatigued driving" between December 2009 and October 2010 -- twice in New Jersey, twice in Pennsylvania and once in Connecticut, records show.
Police said Williams told investigators that the incident occurred the morning of March 12 after he swerved to avoid a tractor-trailer that might have clipped the bus. The bus then flipped on its side and smashed into poles, which cut through two-thirds of the vehicle. Williams has not been charged.