His partner's son had a small cut across his neck from the seatbelt on his booster seat.
"It's just a graze really but it's a good thing we bought that bloody car seat.
"That car booster seat saved his life."
The man had been heading towards Featherston for a doctor's appointment.
Wairarapa road policing manager Sergeant Chris Megaw said the first car was turning into Fleet St when the van ran into the back, then the black car behind the van smashed into the back of the van.
No one was hurt, he said.
"It's just one of those things that happens on a busy main street in Masterton."