A man is lucky to be alive after his car was hit by a van as he changed a tyre in the middle of the Eastern Freeway on Friday morning.

Camera operators at the VicRoads traffic management centre watched in disbelief as the man set about changing his tyre in one of the middle lanes on the freeway at Bulleen about 6am.

"He was in the outbound lane, second from the left," a VicRoads spokesman said.

Witnesses told radio station 3AW they saw the man underneath his vehicle near the Chandler Highway.

He managed to jump out of the way and run to safety when a van coming around a bend smashed into his car and rolled.