Trucks carting millions of cubic metres of spoil out of the inner city as the Melbourne Metro rail tunnel is dug will be fitted with protective sideguards designed to reduce the risk of cyclists, motorcyclists and pedestrians getting killed.

The protective bars, called side underrun protection rails, stop a person from being dragged beneath a truck's wheels in a collision, instead knocking them out of the truck's path.

Trucks working on the Metro tunnel project will have side-guards to prevent cyclists being run over. Credit:Glenn Hunt

It is the first time heavy vehicle sideguards have been mandated on a major project in Victoria and follows the example of London's enormous Crossrail project.

The task of removing about two million cubic metres of spoil - soil, dirt and rubble resulting from an excavation - from the rail tunnel work sites is expected to require more than 340,000 truck trips around the inner city, many of them near popular bike routes.