Humberside Police say they had no choice but to shoot a man who was brandishing a sword and ignoring repeated warnings from armed officers.
Simon Murden was the first person to be shot and killed by the force
Simon Murden, 26, from Beverley, was shot dead by police as he approached them with the weapon on the A63 near Hull early on Tuesday morning.
Baton rounds did not stop Mr Murden and officers opened fire said Humberside Assistant Chief Constable John Crosse.
Mr Murden's family said their son was brought up a committed Christian.
The family said Simon Murden had recently returned from a trip to Africa.
In a statement his parents David and Dorothy added: "The family is not aware of all the details surrounding Simon's death and so cannot and will not answer questions."
The force has confirmed it is the first time a person has died as a result of a Humberside Police armed operation.
The Independent Police Complaints Commission (IPCC) is to conduct an investigation.
Police had sent armed officers to the area after they were told a van was being driven in the wrong direction near Welton at 0620 GMT.
Mr Crosse told a news conference: "As is force procedure, the deployment of armed officers was authorised by a chief officer.
"It is reported that the man began to approach the police officers.
"Baton rounds were fired but they failed to stop the man in his approach. A conventional firearm was then used and the man was hit."
The van comes from a shop in Beverley
Police closed off the A63, which is a continuation of the M62 and the main route into Hull from the west, until early evening.
A major investigation at the scene is being carried out near a Little Chef restaurant and a petrol station at the side of the dual carriageway about 10 miles west of Hull.
Eyewitness Paul Hankinson told BBC News he had seen a police car pursuing the van down the A63.
"The next minute we heard this almighty bang and we thought 'what the hell was that?'.
"We thought that's someone behind us.
"The next minute we saw that van behind us coming up facing the wrong way towards the carriageway followed by a cop car."
The van came from a charity shop in nearby Beverley. A sign on the door of the shop said it was closed because of a bereavement.
The 'And Albert Foundation' shop in Beverley sells Fair Trade goods and has its own "Trading Roots" labelled products.
Humberside's Chief Constable David Westwood visited Mr Murden's family to explain the circumstances of the incident to them.