Upper House Member for Western Victoria Gayle Tierney said work had begun on a business case to look into ways to give drivers on the route more chances to overtake safely.

The business case is being prepared as part of the process to set the state government’s budget for 2018-2019.

Ms Tierney said traffic modelling and safety assessments would be done as part of the business case.

The business case would identify where along the highway overtaking lanes should be built along with more safety barriers to get the greatest safety benefit.

During the past five years, there have been four lives lost from 13 head-on collisions, two lives lost from 46 run-off road crashes and three serious crashes from drivers trying to overtake vehicles on the Princes Highway.

Ms Tierney said that as Victoria’s economy grew, adding extra overtaking lanes would get timber, train, dairy and agriculture products to the Port of Portland and the Port of Geelong more efficiently.

The move to develop a business case for more passing lanes follows a long campaign from several quarters for the initiative.

Those pushing for the upgrade have included south-west councils through the Great South Coast group, Member for Western Victoria James Purcell and the RACV. Mr Purcell last year called for 50 passing lanes between Colac and the border.

The Great South Coast group of municipalities has lobbied for the two-plus-one road design which has a continuous three-land cross section with alternating passing lanes. 

Some European studies show the design has reduced crash fatalities by up to 90 per cent where wire rope medians separate oncoming traffic.

RACV roads and traffic manager David Jones said the two-plus-one delivered significant safety benefits for low traffic volumes.