A man has been arrested in connection with what police described as a road-rage incident.
The attack happened at about 1600 BST on Saturday on Shepherd Drive in Ipswich near the Baptist Church.
The 29-year-old man was stabbed in the stomach.
The victim was driving a white panel van. His injuries are not said to be life threatening.
A 20-year-old man from Ipswich is being questioned by police.