One of the survivors of the crash recalled seeing a big dust of smoke as a truck crossed the centre barrier and ploughed into the van he was travelling in, killing three of the Samoan seasonal workers inside.
This is a companion discussion topic for the original entry at https://www.stuff.co.nz/nz-news/360944614/fatal-sh1-crash-survivor-saw-dust-smoke-heard-men-yelling-truck-crossed-centre-barrier