Stretch limousines are often converted cars or 4WDs. Lengthening the vehicles and adding new seating configurations can undercut the federally mandated safety features designed by the original manufacturer, according to crash-worthiness experts.
"Once you start modifying the vehicle, you pretty much undo all of that," said Raul Arbelaez, vice-president of the Insurance Institute for Highway Safety's vehicle research center in Virginia.
"When a vehicle is stretched, the main thing that's taken into account is to make sure that it is structurally stable and roadworthy in order to carry the occupants and handle the load and be durable, not necessarily to withstand any crash forces."
The addition of several thousand kgs of additional frame and sheet metal from the longer body and the added weight of carrying more than a dozen passengers also puts far greater strain on a stretch limo's brakes and tyres than they were designed for, he said.
"There's a bit of a Frankenstein approach, where a vehicle is chopped up and put back together with parts that were not originally designed for that vehicle," said Deborah Hersman, president of the National Safety Council advocacy group and a former NTSB chair. "It's clear that they don't have the same safety design standards as those same vehicles had before they're stretched or modified."
There's a bit of a Frankenstein approach, where a vehicle is chopped up and put back together with parts that were not originally designed for that vehicle
The fatal crash highlights a number of shortcomings in such vehicles, including crash worthiness, seat belt use and the patchwork of state and federal regulations that provide inadequate oversight, Hersman said.
"This is an area where we clearly have a gap that needs to be addressed and it's incumbent upon state policy makers and the feds to work together and address this," she said.
The crash occurred at the Apple Barrel Country Store off a T-junction where two highways meet. A manager of the store said the limo was coming down the hill at "probably" 60 mph (95 km/h), the New York Times reported.
One issue the NTSB agency will be looking at is New York's lack of a requirement that limo passengers wear seat belts, Sumwalt said. Investigators still hadn't determined whether passengers were restrained as of Monday morning.
Three years ago, after four women died and two others were seriously injured in a limo accident on Long Island, New York Senator Chuck Schumer, D, called for an investigation into federal safety standards.
"It's clear that stretching a limo can put the wheels in motion for a terrible tragedy," Schumer said then in a press release. "All too often, stretched limousines lack basic safety protections, including not enough side impact air bags, rollover bars, appropriate exits and more."
A similar safety issue arose in the 2014 crash that injured comic Tracy Morgan and killed his friend, comedian James McNair: The luxury limo van had been modified to block exit doors, which made it difficult to reach the victims.
Morgan was returning from a show on June 7, 2014, when a truck struck the limo from behind. It took emergency workers more than 30 minutes to remove the injured passengers, according to the NTSB.
There was only one side door in that limo's passenger compartment, the NTSB found, and there were no regulations to prevent such modifications. The NTSB in 2015 called on the National Highway Transportation Safety Administration to adopt new regulations requiring at least two exits on such limos.
NHTSA is still evaluating the recommendation, according to correspondence on the issue on NTSB's website.
- Bloomberg