Four truck drivers face multiple criminal charges in connection with four transport truck collisions over the summer that led to the deaths of 10 people, and injured dozens.

Ontario Provincial Police said Thursday morning during a news conference they have completed their investigations into four separate crashes that were all caused by "driver inattention" — when the operator isn't paying full attention to the road because he or she is fatigued or distracted.

OPP commissioner J.V.N. "Vince" Hawkes told reporters these collisions share a number of common elements, which all "resulted from an inattentive truck driver slamming into the line of either slowed or stopped traffic" on a highway due to road construction or a collision ahead.

"This is driver inattention at its worst," said Hawkes.

Smoke rises above the scene of a fatal collision on Highway 401 in Port Hope, Ont., on Aug. 3. (Pascal Marchand/CBC)

The most recent incident occurred on Aug. 3 along eastbound Highway 401 near County Road 28 in Port Hope, Ont.

A transport truck "failed to slow down" as it approached the construction zone, Hawkes explained.

"His truck came crashing into the end of the traffic queue, resulting in the cab of the truck, two passenger vehicles becoming totally engulfed in flames," he said.

Both a 26-year-old man and a 35-year-old man, who were inside the vehicles, were killed. Two others were seriously injured.

The driver of the transport truck, a man, 56, of Brampton, is charged with two counts of dangerous driving causing death and two counts of criminal negligence causing death.

Driver charged in 6-vehicle crash near Chatham

Another truck driver is facing several charges for a six-vehicle crash that killed a mother and her son near Chatham, Ont., this summer.

The collision happened on the afternoon of July 30 along Highway 401 near Dillon Road. Traffic was stopped due to a separate crash in the eastbound lanes.

Lacie Brundritt, 42, and her son Kyle, 14, were killed in a six-vehicle crash on Highway 401 on July 30. (Families First)

Lacie Brundritt, 42, and her son Kyle, 14, were in a pickup truck with two other people when a tractor trailer heading west collided with several vehicles around 4:40 p.m., according to OPP.

The pickup truck, which was hauling a camper trailer, was "crushed upon impact," Hawkes said.

"The transport truck then mounted the pickup truck and the two vehicles continued to collide with five other vehicles before finally colliding with another transport truck in the line of that traffic," he added.

Brundritt's husband, 39, and other son, 12, were also in the pickup truck when it was struck from behind. They were seriously injured.

The family was on their way home from a camping trip.

The transport truck driver, a 52-year-old man of Brampton, is charged with two counts of dangerous operation of a motor vehicle causing death and three counts of dangerous operation of a motor vehicle causing bodily harm.

3rd crash occurred in construction zone

Five vehicles, including three gravel-hauling transport trucks, were involved in the fatal crash on July 27 in Georgina, Ont. (Martin Trainor/CBC)

The third collision happened on July 27 in Georgina, Ont. when a double dump truck hauling gravel collided with five-vehicles.

The driver "reportedly failed to slow down on its approach into the construction zone and crashed into the back of an SUV," said Hawkes.

The noon-hour crash on Highway 48, near Old Homestead Road involved three gravel-hauling trucks, a commercial vehicle and a passenger vehicle, OPP said.

Two people died and a child was among two critically injured in a multi-vehicle crash in Georgina, Ont. (Martin Trainor/CBC)

Both the passenger of the commercial vehicle, a 34-year-old man, and the driver of the SUV, a 44-year-old man, were trapped in the collision. They died at the scene.

An adult and 10-year-old child in the vehicles were airlifted via Ornge air ambulance to trauma centres with critical injuries.

The driver of the dump truck, a 37-year-old man of Toronto, is charged with two counts of dangerous operation of a motor vehicle causing death, two counts of dangerous operation of a motor vehicle causing bodily harm and one count of dangerous driving.

Driver charged in Kingston crash that killed 4

The fourth fatal collision involving a transport truck occurred on May 11.

Four people died and two others were seriously injured in a seven-vehicle pileup on Highway 401 east of Kingston, Ont.

The crash happened around 1:30 a.m. and involved four tractor-trailers, a commercial truck and two cars.

"The driver of the transport truck approached the construction zone and failed to stop, crashing into the vehicle at the end of the traffic queue," said Hawkes.

"The impact was such that the vehicle was crushed and became engulfed in flames."

The four people who died in Highway 401 crash near Kingston, Ont., were in one car that became engulfed in flames after a collision. (CBC)

All four people in the car that burst into flames — a man, 40, his partner, a 44-year-old woman, her 25-year-old son, and a 21-year-old family friend — were pronounced dead at the scene.

The transport truck driver, Dunhill Tabanao, 37, of Vaudreuil-Dorion, Que., was charged with four counts of dangerous operation of a motor vehicle causing death and two counts of dangerous operation of a motor vehicle causing bodily harm.

'Can't do it safely, you shouldn't be doing it'

Hawkes called all these recent collisions a tragic reminder of "the tremendous toll on the lives of innocent citizens when commercial transport truck drivers are not paying full attention to the road."

Lynn Bevand's sister Karron Mitchell-Derbyshire was killed in 2014 when a transport truck slammed into the back of her car on Highway 400 near Barrie. Bevand told reporters her life changed forever after that day.

"My world instantly collapsed," she said.

Between 2015 and 2016, the OPP responded to 13,668 collisions that involved transport trucks, in which 155 people were killed.

As of Oct. 15 this year, there have been more than 5,000 transport truck-related collisions, Hawkes noted. A total of 67 people have died in 56 collisions involving transport trucks, he said.

"In the words of my sister, if you can't do it safely you shouldn't be doing it," said Bevand.

Lynn Bevand remembers her sister, Karron, who died at the hands of a negligent driver in a collision on March 5, 2014 <a href="https://twitter.com/hashtag/NeverForgotten?src=hash&ref_src=twsrc%5Etfw">#NeverForgotten</a> <a href="https://t.co/oKk7vB1Qsp">pic.twitter.com/oKk7vB1Qsp</a> —@OPP_News

The OPP are cracking down on driver inattention-related deaths as a result.

Police are doing this through a mitigation strategy that aims to reduce the number of commercial motor vehicle collisions, said Hawkes.

This includes a better analytical understanding of where, when and how these crashes occur to develop new resources to combat driver inattention, he explained.

One such tactic is to use of the OPP helicopter more frequently, said Hawkes.

He also called for the province's Ministry of Transportation and the Ontario Trucking Association to commit to this strategy.

"There's zero room for error, carelessness, negligence and poor driving behaviour of any kind," said Hawkes.

'These accidents hurt us'

But these efforts aren't enough to bring victims back, family members say.

Nicolle McGee's boyfriend Todd Gardiner was killed in the crash near Port Hope, Ont., in August. He was travelling with his cousin, Mike Glazier, to play in a golf tournament for his dad's birthday when they were struck from behind by a transport truck that failed to slow down.

'The impact needs to start being about who the victims were, not how they died,' said Nicolle McGee whose would-be fiancé, Todd Gardiner, was killed in August. (CBC)

McGee, wearing a shirt monogrammed with a photo of the cousins, also gripped a photo of Gardiner as she described what they had planned for their future.

"I think it needs to be stated that these accidents hurt us; they hurt the families; they hurt everyone," she said.

"The impact needs to start being about who the victims were, not how they died."

Debbie Glazier's son, Mike, left, and Pauline Gardiner's son, Todd, right, were killed by a transport truck in August. They were cousins. (Martin Trainor/CBC)

Glazier's mom, Debbie, added that these fatal collisions are preventable.

"These things should not be happening," she told CBC Toronto.

"This has got to be stopped somehow, these truck drivers. They're destroying lives every day."