A motorcyclist has been killed on Melbourne's Monash Freeway, forcing its closure to city-bound traffic.
Assistant Commissioner Stephen Leane said the rider was running in between lanes when killed during Wednesday morning peak hour.
"We're not sure about whether speed was an issue, but obviously it's a high speed road," Mr Leane said.
"Sadly he collected one car on one side and then ended up underneath a B-double truck.
"He's now lost his life."
The incident has led to delays, with the freeway closed city-bound at Springvale Road.
Motorists are advised to exit at the earliest chance and use the Princes Highway instead.
Mr Leane said police are trying to reconstruct how the crash happened.
"Either way, he's taken a dangerous manoeuvre in high traffic, run the risk and he's lost his life today."