Suburban Melbourne roads will be upgraded in a $2.2 billion package as part of the state budget.
The overhaul of 13 arterial roads within five years will not require any land acquisitions and will not be tolled.
"It's about more road and better roads to get people home sooner and safer and to also move our freight task around the suburbs more efficiently," Premier Daniel Andrews told reporters on Sunday.
"These are all singled out by the RACV as real priorities, they've been affected by congestion for far too long."
Motorists will experience delays during the construction of 550km of extra road, Mr Andrews warned.
"But if we don't have some congestion due to construction now, we will have nothing but congestion in the future," he said.
The northern and southeastern suburbs are being targeted by the package.
In the north, more than $1 billion of the funds will go to widening and improved safety measures for Sunbury Road, Craigieburn Road, Epping Road and Childs Road.
Healesville-Koo Wee Rup Road in Packenham, Lathams Road in Carrum Downs, Narre Warren-Cranbourne Road in Cranbourne and Pound Road West in Dandenong South will all get upgrades in the southeast.