"I came out to have a look. It was damage everywhere," said the man.
Higgins workers were sitting on the side of the road "in shock".
Trustpower TECT Tauranga Rescue Helicopter pilot Todd Dunham, who flew the man to Tauranga Hospital, said the "horrific" crash scene was one of the worst and "most chaotic" he had seen in his nine years flying for the service.
Dunham said three road workers were hit by a "truck coming down the road and now they've lost their lives".
He said the truck that appeared to have hit the road workers also struck a Higgins truck, tipping it upside down into a ditch.
The other truck that had been "opened up like a can of sardines" was also in the ditch.
Ross Taylor, the chief executive of Higgins' parent company Fletcher Building, said at the time that two of those who died were employed by Higgins and one was a contractor working for the company, while the two injured people were contractors.
"This is an absolute tragedy, and we are moving to offer our support to those affected and to our people in the area."