One of the first people on the scene of a fatal crash between a milk tanker and a car in Shannon this week said she could hardly comprehend what she was seeing.

Erin Willson said she was on the way to pick up her kids when she came across the horror crash shortly after it happened on Wednesday afternoon.

“I was headed north. From my view, the tanker was jack-knifed across the road with the tail away from me. The cab of the tanker was in the southbound lane with the car crashed into it. From my view, the car was very crumpled in the northbound lane facing the wrong direction with the license plate to me,” she said.

The car quickly caught on fire, she said.

Two people, the occupants of the car, died as a result of the crash, while the Fonterra truck driver was moderately injured. The crash happened on State Highway 57, near the small town of Shannon, south of Palmerston North.

Erin Willson's car was written off after a crash on State Highway 57.

Willson said she was “in shock” at the scene before her.

“I could see the accident from very far away since it is a straight [road] on a rise. My eyes couldn’t comprehend it until the truck in front of me put on his emergency blinkers. It didn’t look real,” she said.

People were already rushing to help as Willson came through.

• Serious crash near Shannon, road expected to be closed for several hours
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She said that stretch of road has always been “shocking”. Willson was in a car crash in that area 18 months ago with all her children in the car. Nobody was injured, but her car was written off.

“My theory is since it is a straight road people check their phones [or] don’t pay attention. When we got hit, she said ‘I didn’t even see you’. I was like ‘how?’”

“They did put up a barrier on that straight approximately five to six years ago which now means tractors can’t 100 per cent get off the road, and makes this hazardous.

“In my accident, a milk tanker pulled off a farm along there in an attempt to get off the road - so between the barrier and the actual lane - but there just wasn’t enough space hence us all slamming on brakes, but the car behind me not noticing.

“Previously when we first moved here there was enough space on that straight for vehicles to get out of the lane.

“I think it was safer before the barriers. I don’t know road safety stats - do those barriers prevent more lethal accidents? I have no idea. But I do know farm vehicles don’t have the space to get off now and it is a dangerous stretch of road.”

A friend of hers was also involved in a near-fatal crash on that stretch of road two years ago, and she recalled another crash in the area about three months ago.

Meanwhile about five weeks ago a truck was blown over by the wind on that road as well, she said.

Police closed the road after Wednesday’s crash, with the Serious Crash Unit investigating overnight.

A resident, who lives about 1km from the crash site, said he heard a loud bang and saw a car burst into flames.

“I can see a Fonterra milk tanker down there,” he said on the day of the crash.

“There was quite a loud bang when we were sitting at the table [at home] so we stood up and saw the smoke coming from the front of the tanker.”

The man continued, “There was smoke coming from the car too. Then it burst into flames. The flames were as high as the tanker.”

A farmer, who works east of Shannon, also told the Herald he saw a plume of black smoke.

The tanker driver was moderately injured, he said, and Fonterra was supporting him.

A Fonterra tanker was involved in the crash, a spokesman for the company confirmed to the Herald.

Melissa Nightingale is a Wellington-based reporter who covers crime, justice and news in the capital. She joined the Herald in 2016 and has worked as a journalist for 10 years.