Horrific and avoidable cause of 2022 Oklahoma crash that killed six teenage girls when their car was ripped apart by semi is revealed

The horror crash that killed six teenage girls in Oklahoma two years ago was likely caused by the driver being impaired by marijuana.

Madison Robertson, 16, was driving her five school friends on March 22, 2022, when she failed to stop for an oncoming truck and their car was ripped apart. 

She and her friends Gracie Machado, Brooklyn Triplett and Austin Holt, all 15, and Addison Gratz and Memory Wilson, both of 17, died in the crash.

A National Transportation Safety Board (NTSB) investigation into the incident found Robertson slowed down for an intersection and then accelerated past a stop sign because she was likely impaired by recent marijuana use.

Its chairwoman Jennifer Homendy is now urging parents to warn teenagers about the risks of driving after smoking weed.

The horror crash that killed six teenage girls in Oklahoma two years ago was likely caused by the driver being impaired by marijuana

Madison Robertson, 16, was driving her five school friends on March 22, 2022, when she failed to stop for an oncoming truck and their car was ripped apart

Robertson, from Tishomingo in Oklahoma, had five friends in her 2015 Chevy Spark when she failed to yield for a truck being driven by Valendon Burton, 51, at a notorious junction.

The car, designed to carry four people, saw its roof ripped off in the collision and the vehicle ended up 300 feet away. 

A toxicology report found cannabis in Robertson's system but she tested negative for alcohol.

Tests on blood found a THC concentration of 95.9 nanograms per milliliter. 

She also broke the law by driving on an intermediate driver's license without the supervision of an a fully-qualified driver aged 21 or older.

Burton was found to have neither drugs nor alcohol in his system, and did not face any charges. 

The NTSB report stated the teenager was likely impaired by marijuana and distracted by her five friends in the car. 

It found Robertson slowed down at the intersection to one mile per hour but then accelerated past the stop sign.

A gravel truck tried to avoid the girls but struck the driver's side door of their vehicle at 50 miles per hour and all six teens died of multiple blunt force injuries.

The Oklahoma Highway Patrol found vaping mouthpieces and cannabis buds in the car following the crash. 

Homendy said: 'There’s a perception that in states where it’s legal that it’s safe and legal to drive impaired on marijuana.'

Robertson friends: Addison Gratz, Austin Holt, Memory Wilson, Gracie Machado and Brooklyn Triplett all died in the crash. NTBS said Robertson had broken the law by driving without the supervision of a licensed driver 21 or older

NTSB and the Oklahoma Highway Patrol concluded that Robertson failed to yield at a stop sign on the Oklahoma 22 highway, causing the truck to slam into the car

In the crash report, the NTSB highlighted studies which show the drug slows reaction time, decreases motor coordination and impairs judgment of time and distance.

Oklahoma does not allow recreational use of weed but is legal for medical purposes.

But it is illegal to drive while under the influence of marijuana in every state across the country. 

A safety alert was issued by the NTSB which urged parents to talk to their children about how the drug can impact driving. 

'Unfortunately, I think state laws that are legalizing recreational and medicinal use of marijuana have really come before thoughts or action on what are they going to do about traffic safety,' chairwoman Homendy said. 

'They are far ahead on legalizing it, but very behind when it comes to traffic safety.' 

She added that police departments need to start enforcing laws against driving while impaired by cannabis to deter people. 

A gravel truck tried to avoid the girls but struck the driver's side door of their vehicle at 50 miles per hour and all six teens died of multiple blunt force injuries

A National Transportation Safety Board investigation into the incident found Robertson slowed down for an intersection and then accelerated past a stop sign because she was likely impaired by recent marijuana use

The NTSB said in Washington, where recreational marijuana has been legalized, more drivers involved in fatal crashes have tested positive for the drug since it became legal.

It has asked the Oklahoma State Department of Education to develop a drug and alcohol abuse program to warn children about the risks of smoking weed and driving.

Massachusetts and Rhode Island are the only states to have similar courses, according to the government agency.

'We have to start communicating well ahead of time, to kids, that driving, having ingested or smoked or inhaled marijuana is impairing, and it’s a risk to them and a risk to others,' Homendy said. 

The Governors Highway Safety Association said that cannabis-impaired driving is a growing concern.