Two people went to Te Kūiti Hospital with minor injuries after the Lawrence St crash, police said.
Segments of debris from the car were scattered over the tar-seal road and those at the scene told Stuff there were two occupants.
The driver “was not too bad” but the passenger had a “few bruises and cuts”.
“It was a wee Mazda hatchback, I’m surprised there wasn’t any fatalities,” they said.
“That steel bar would have taken off someone’s head, it’s gone straight through … it’s pretty vicious.”
After the crash, a bridge was cordoned off by people who appeared to be locals in high-vis gear, but police were yet to confirm this.
The witness said it was quite odd that the car had ended up on the wrong side of the road.
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They noticed water on the road which they thought may have contributed to the crash.
“The car must have been coming into Te Kūiti on the left-hand side and somehow veered across the road,” a witness said.
“The car has just rammed straight into a safety barrier, and it’s just gone right through and out the other side.”
Police said they “spoke to the people involved at the hospital and enquiries are ongoing”.
Police have been approached for further comment.