PALM SPRINGS, Calif. — Felony manslaughter charges have been filed against a semi-truck driver who authorities say caused a deadly bus crash near Palm Springs killing 13 people and injuring 31 others after falling asleep at the wheel.

On Oct. 23, 2016, 13 people died after their tour bus collided with a big rig on Interstate 10 near Palm Springs. The National Transportation Safety Board on Oct. 31 will announce results of its year-long investigation into the collision.

Bruce Guilford, 51, of Covington, Ga., stopped for traffic in the far-right lane of Interstate 10 on Oct. 23, 2016, and dozed off, authorities say. While Guilford was sleeping, traffic began moving again, but his vehicle continued to block the westbound lane, according to a declaration in support of an arrest warrant filed Wednesday in Riverside County Superior Court.

The tour bus, which was returning to Los Angeles from the Red Earth Casino near Salton City, hit the rear of Guilford's trailer at a speed of 76 mph, according to court documents.

Guilford faces 13 counts of felony vehicular manslaughter with gross negligence, authorities stated. It was unclear Thursday if he was in custody.

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In addition, according to court documents, he is being charged with 11 counts of felony reckless driving with injury and 18 counts of misdemeanor reckless driving with injury.

Charging documents indicated he has continued to work as a bus driver since the crash.

In the days before the fatal accident, Guilford violated federal regulations for truck drivers and falsified his drivers log, investigators said.

"In the 24 hours preceding the collision, Mr Guilford had only 7 hours of sleep opportunity, but it is unlikely that he actually slept during those opportunities," the arrest declaration states.

On Oct. 23, 2016, 13 people died after their tour bus collided with a big rig on Interstate 10 near Palm Springs. The National Transportation Safety Board on Oct. 31 will announce results of its year-long investigation into the collision.

Investigators also say Guilford violated federal regulations while working as a cross-country truck driver in the weeks leading up to the crash, including falsifying his work logs. He also failed to take the mandated 34-hour rest period before making another cross-country trip on Oct. 19, according to the arrest declaration.

It adds, however, Guilford is not the person most at fault for the crash, an indication that investigators believe the driver of the tour bus was also at fault.

A "very traumatic" collision

Crash victim Gustavo Garcia's photo is attached to a makeshift memorial that has been visible along Interstate 10 for months, and behind it are the names of his relatives who signed it in his memory.

Just a few steps away is a memorial for Teodulo Elias Vides, who drove the USA Holiday tour bus occupied by Garcia and 42 other people when it slammed into a big rig on westbound I-10.

Each victim was from Los Angeles and the makeshift memorials are the only local reminders that 13 people died and 31 others were injured on Oct. 23, 2016.

The National Transportation Safety Board oversaw the investigation that's expected to come to a head Oct. 31, spokesman Eric Weiss said. During a board meeting, NTSB staff will discuss their findings and make recommendations for long-term safety measures.

"It definitely will get into details," Weiss said. "The investigation was wide-ranging and in depth."

Similar meetings usually last several hours and they're occasionally attended by crash victims or their families. Weiss said he didn't know if anyone from the bus crash would be in attendance Oct. 31, but discussions may be beneficial to travelers across the country.

Roadside memorials are visible along Interstate 10, where a tour bus crashed into a big rig Oct. 23, 2016. The collision left 13 people dead and 31 others injured.

"It could help prevent accidents like this from happening in the future," Weiss said.

In the past year, at least 10 lawsuits have been filed by surviving victims or family members of the deceased and they're in the process of being consolidated, according to the law firm representing one of the survivors, Gloria Campos of Los Angeles.

The collision woke her up and she suddenly found herself across the aisle, attorney Marilyn Nelson said. Campos had injuries to multiple parts of her body and suffered dizziness following the collision and she still has limited range of motion in her neck.

"It was a very traumatic event," Nelson said.

This photo shows the USA Holiday tour bus that was destroyed after colliding with a big rig on Oct. 23, 2016. Thirteen people died in the collision and 30 others were injured.

Firefighters swarmed the scene and spent several hours removing victims from the wreckage that sat in the middle of an empty westbound freeway. One by one, bodies were laid on the ground and covered in tarps and blankets.

A tow truck was used to lift the big rig and provide easier access to the bus. Hours passed before the vehicles were separated and removed from the scene.

A preliminary NTSB report showed the big rig and other traffic moved slowly on I-10 because of utility work, which involved Southern California Edison crews moving electrical wires that crossed the road from a wooden pole structure to a steel pole.

Families of the victims have named USA Holiday, Caltrans, Southern California Edison, Riverside County, Palm Springs and Desert Hot Springs and the bus' manufacturer in their civil suits.

Their complaints mostly blame the defendants for not providing adequate lighting or signage for the roadwork. The accusations are all denied, according to court records.

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