A 68-year-old man was killed while on foot on the M61 after shortly after visiting a nearby service station.
Police are appealing for information about what happened to Stephen Hayes prior to his death in the early hours of Friday, April 11.
Mr Hayes, who was from Blackpool, was hit by a vehicle on the M61 northbound, just north of Rivington Services between junctions six and eight around 1.30am.
It is thought that he was on foot on the motorway after previously visiting Rivington Services, and he has then been struck by a lorry.
An investigation into the circumstances of the incident is under way and officers are appealing for anyone with any information to come forward.
Roads policing officer Sgt Finn Quainton said: “We are still trying to piece together exactly what has happened and why Mr Hayes has come to be on foot on the motorway.
“I would urge anyone who was in the area at the time, who may have any information to come forward.
“We have informed Mr Hayes’ next of kin and specially trained officers have been with the family and continue to offer their support through this very sad and difficult time.”
The M61was closed between junctions six and eightnorthbound overnight.
The lorry driver was not arrested after the incident.
Anyone with information can contact police on 101 quoting motorway log 66 of April 11.