A Long Island mom guzzled vodka and smoked pot in a minivan packed with young kids before speeding the wrong way down the Taconic Parkway, sparking the head-on collision that killed eight, authorities revealed yesterday.

Diane Schuler had knocked back the equivalent of 10 shots of 80-proof booze and smoked marijuana as recently as 15 minutes before the horrific July 26 smash-up, officials said.

Cops later found a broken 1.75-liter bottle of Absolut vodka inside Schuler’s van, which burst into flames after the crash, said State Police Maj. William Carey.

The crash killed Schuler, her 2-year-old daughter and three young nieces, as well as three men in the car she hit. Her 5-year-old son miraculously survived the crash.

Schuler had a blood-alcohol content of .19 percent — more than twice the legal limit of .08 percent, authorities said. She also had 6 grams of undigested booze in her stomach, they said.

In addition, the West Babylon resident had “a high number” — 113 nanograms per milliliter — of THC, the active component of marijuana, in her bloodstream, said Betsy Spratt, chief toxicologist with the Westchester DA’s Office.

That indicated Schuler smoked pot 15 minutes to one hour before the crash, Spratt said.

With the alcohol alone, Schuler, 36, “would have had difficulty with perception, with her judgment, with her memory,” Spratt said. “Around that level of alcohol, you also start to get tunnel vision.”

When combined with marijuana, “those effects are intensified,” she said.

Schuler’s husband, Nassau County public-safety officer Daniel Schuler, has told police that his wife occasionally smoked pot and was a social drinker, WCBS-TV reported.

Schuler’s relatives were informed of the toxicology results after the funerals for the family late last week.

The relatives of her other victims were outraged when they learned about them yesterday.

“We were victims the first time, but now we feel like we’re being victims all over again because she made that choice,” said Roseann Guzzo, whose 49-year-old brother, Guy Bastardi, and father, Michael Bastardi, 81, were killed when their SUV was hit by Schuler’s van.

“It’s horrendous,” Guzzo said. “It’s making it worse for us now.

“How do you put five children in a car when you’re a mother who’s a drunk?” she asked. “It’s crazy.”

Outside the Floral Park, LI, house of Schuler’s brother, Warren Hance, whose three daughters died in the tragedy, a neighbor said, “She’s gonna burn in hell.”

Carey, of the State Police, said that before the toxicology results, “We simply had no evidence that drugs or alcohol [were] at play . . . We do not have much in the way of people that morning describing Diane Schuler, other than saying she was fine.”

While police do not expect to criminally charge anyone in the case — which has been classified as a homicide by the Westchester County Medical Examiner’s Office — they plan to further investigate the events that lead to the horrific cash.

“At this point, we’re getting limited information from the family,” Carey said. “Obviously, the family is going through a grieving process. We’ve conducted some interviews with family members. We have not conducted as many interviews as we would like.”

The disclosure that Schuler was heavily intoxicated cleared up some of the mystery that had surrounded the smashup, which occurred about four hours after she left an upstate campground with no apparent signs of intoxication.

The most perplexing question had been why Schuler, who was on her way home, would have entered the Taconic near Briarcliff Manor going the wrong way — southbound in the northbound lane — and continued on for nearly two miles before hitting the Bastardis’ SUV.

For days, there had been speculation that the Cablevision executive had become disoriented because of a previously unknown medical condition or that she was suicidal.

Schuler had spent the weekend with Daniel, their 2-year-old daughter, Erin, 5-year-old son, Bryan, and three nieces — the Hance girls Emma, 8, Alyson, 7, and 5-year-old Katie — at the Hunter Lake Campgrounds in upstate Parksville.

The Schulers had been regular visitors there for the past three years, according to campground owner Ann Scott, 76.

“They’re an ordinary family like you or I or apple pie,” Scott said. “I’ve never seen them have an argument, never seen them with a drink. All they did was relax on their site with their kids.

“I swear on my grandmother’s Bible, I’ve never seen them with a drink in their hand.”

The Schulers separately left the campgrounds at about 9:30 a.m. on July 26. Daniel was driving with the family dog in his Dodge pickup, while Diane was taking the children in her Ford Windstar minivan.

Daniel could not follow Diane onto any parkway because his truck has commercial plates.

“She was fine. She was the same old Diane she was every weekend,” said Scott. “The last words I said were, ‘Have a safe trip home.’ ”

But the trip soon went horribly wrong. Schuler stopped at a McDonald’s on Route 17 in Liberty and then headed onto Interstate 87, where numerous witnesses saw her driving recklessly.

She then turned east onto the highway and was seen driving across a grass divider at the Ramapo service area.

At 1 p.m., she crossed the Tappan Zee Bridge heading east. Two minutes later, Schuler pulled over and called her brother, Hance, who was at home, and said she was having trouble seeing and was disoriented. During that eight-minute call, Hance also spoke with his daughter Emma.

It was unclear if Hance knew his sister had been drinking, but he told her to stay put and he would come get her. Schuler instead drove off, and bizarrely dropped the phone off at a rest stop.

Hance then called police to alert them about his sister’s call, but they were unable to locate her in time.

Schuler was supposed to get on the Saw Mill River Parkway heading south but ended up getting on the Saw Mill north.

She then made her way to the Taconic — where she entered via an exit ramp and headed south in the northbound lanes, terrifying other drivers who swerved across three lanes to avoid her.

It was on the Taconic at 1:35 p.m. — after going 1.7 miles the wrong way — that the minivan smashed head-on into the SUV carrying the Bastardis and their friend and fellow Yonkers resident, 74-year-old Daniel Longo.

An upstate couple, Angela and Dean Tallarico, also were injured when their SUV was hit by the Bastardi’s vehicle after the initial crash.

When a reporter yesterday told Angela Tallarico of Schuler’s intoxication, she burst into tears.

“Oh, no!” she cried before calling out to a co-worker, “She was drunk!”

Daniel Schuler ducked reporters yesterday after visiting Bryan at Westchester Medical Center in Valhalla, where the boy was in stable condition, a source said.

Michael Bastardi Jr., another son of Michael Sr., said “I’m just kind of in disbelief” and “numb.”

“We want to figure out what happened.” Scott, the campground owner, said, “This is the most shocking news that I’ve heard in my lifetime.

“If this is true, she’ll be treated like a monster.

“Dear God, what’s her brother thinking at this point? What’s her husband thinking? You’ve lost [four] children, and there’s no reason for it. Everyone’s been turned upside down by this.

“When I learned it this morning, I dropped the phone. It’s absolutely terrible.”

Additional reporting by Kieran Crowley, Austin Fenner, Erin Calabrese, Andy Geller and Perry Chiaramonte

dan.mangan@nypost.com