OLD WESTBURY, N.Y. (CBSNewYork) — Two people were killed and several others were hurt in a crash that shut down the Long Island Expressway for hours overnight Monday into Tuesday in Old Westbury.

For more than six hours, the expressway was closed while investigators worked to collect evidence and clear the wreckage left behind by the accident.

As CBS2’s Dave Carlin reported, the trouble began when a BMW carrying four young people traveling westbound hit the right guardrail and then careened over to the HOV lane between exit 40 and 39 around 11 p.m. Monday, according to police. It was raining at the time.

“This vehicle hit the guardrail on the north side of the LIE striking the guardrail then shot across going southbound if you will across all the lanes of traffic and then it the median divider, the jersey wall, the concrete divider,” Nassau County police Detective Sgt. James Skopek said. “This car then laid at rest right there. What we think and we’re trying to build the facts right now is that the lights were no longer a part of this vehicle.”

All four occupants got out of the car to check for damage, police said. That’s when the 20-year-old male driver and an 18-year-old female passenger were struck by a GMC Yukon.

The impact sent the two standing outside the stalled car flying over the barrier and onto the eastbound lanes, police said.

“He strikes two of those people. One person did actually travel from the westbound portion of the expressway to the eastbound, far, far side of the eastbound lane,” Skopek said.

The man was pronounced dead at the scene. The woman was taken to the hospital, where she also died.

Two other passengers, an 18-year-old woman and 19-year-old man, were hurt and taken to the hospital for treatment.

The driver of the GMC – an off-duty NYPD officer – also suffered minor injuries. The officer was tested for alcohol, the results came back negative.

In April, a driver was struck and killed in a similar crash on the LIE. AAA experts explained what a driver should do if their car is damaged on the highway.

“Get off the highway, pull over to the shoulder, even better look for the next exit and get off there,” said Robert Sinclair with AAA New York. “You don’t want to be standing in the middle of the highway trying to match yourself against cars. Something can happen and very often it does.”

Experts say if you can’t make it to the shoulder, think of your car as your best chance of protection — stay inside with your flashers on and call 911 for help, CBS2’s Magdalena Doris reported.

“When police arrive and they’ve got lights and sirens and all of that when they can safely slow and stop traffic then leave the vehicle,” Sinclair said.

The names of the victims in Monday’s crash have not yet been released.

The investigation is ongoing. Both vehicles have been impounded for brake and safety tests. Police said there is no apparent criminality. They are asking witnesses to come forward to provide any information about the moments leading up to the crash.