Two more signs will be removed from Melbourne roads as part of an audit to find out what caused one to come crashing down on a woman's car. 

The signs hang on gantries along the City Link and the West Gate Freeway and were to be removed on Sunday night because of their similarity to the one that crashed down on driver Nella Lettieri.

“Their removal forms part of further assessments and will assist in the findings of the investigation, together with three signs that were removed (on Saturday) night,” VicRoads said in a statement.

Those three signs passed engineering assessments and showed no signs of deterioration or stress, VicRoads said.

An audit of the other 17 gantries with similar sign support has been finished with no signs of stress or deterioration, said David Clements, Transurban’s program director of major projects Victoria.

Ms Lettieri was travelling along the Tullamarine Freeway when the overhead sign crashed onto her car last Tuesday.

Dashcam footage from a vehicle behind shows the force of the giant sign moving Ms Lettieri’s car even though she had slammed on her brakes.

She escaped serious injury but the weight of the sign crushed her car, shattering the windscreen and scattering glass across the highway. No other cars were hit.