How heat affects roads, trains and planes

Roads can soften, train tracks do expand and, when temperatures are high enough, the book on how to fly some planes literally hasn't been written.

Cars backed up on the Hume Freeway near Seymour.

This is how heat can affect the three modes of transport we depend on most.

They could "melt" or soften and become sticky.

Roads are made up of a gravel base, bitumen and then aggregate (crushed rock).

Professor Frank Bullen specialises in road pavement engineering and says: "The role of the bitumen is to hold the aggregate in place for the traffic to go over."

Read the ABC News story - “How heat affects roads, trains and planes.”