Overtaking lanes in the South West would be blocked off during peak holiday periods including the Easter long weekend under a proposal to improve road safety and cut the road toll.

Main Roads is considering a trial, to begin as soon as this year, to test whether closing overtaking lanes on the busiest days of the year — when thousands of Perth families head south for holidays and long weekends — will improve traffic flow and reduce crashes.

WA Police South West Superintendent Mick Sutherland said the idea was well worth investigating because it could reduce “bottlenecking”, where a line of motorists exceed the speed limit to overtake a slower car and then brake heavily when the overtaking lane comes to an end, creating a double-whammy hazard.

The police boss said 100,000 extra cars were expected in the South West over the Easter long weekend including more than 30,000 on Forrest Highway north of Bunbury and a similar number on Bussell Highway between Bunbury and Margaret River.

He said overtaking zones on single-lane sections of the region’s highways became dangerous in heavy traffic and closing them during the busiest days of the year should be considered.

A Main Roads spokeswoman confirmed the department was “currently reviewing data and looking at options to improve traffic flow on Bussell Highway between Capel and Busselton”, including a trial of shutting down overtaking lanes.

“Closing off overtaking lanes is one of the options being considered for trial and this may occur later in the year,” she said.

It is understood one lane would be blocked with signs and road markers, similar to when road works are ongoing.

Supt Sutherland said he frequently saw near misses in South West overtaking lanes.

“You get to an overtaking lane and people go roaring past at 120km/h or 130km/h with their foot flat to the floor. They forget about the speed limit because they want to get past that car or caravan,” he said.

“It results in a lot of people speeding and it also results in bottlenecking at the end of the overtaking lanes. It creates risk behaviour.

“If you closed down the overtaking lanes people can keep moving at the same speed and you’d keep the traffic flowing at a steady pace.”

Supt Sutherland said he expected the idea to cause debate among motorists but said it was “better to be patient and arrive at your destination than not arrive at all”.

He said the scheme should only apply on the very busiest days as the South West’s highways were clogged with continuous traffic, when “overtaking lanes actually don’t improve traffic flow”.

RAC general manager of corporate affairs Will Golsby said overtaking lanes became dangerous when motorists exceeded the speed limit. But he said generally they made roads safer and he did not support the trial to cordon them off.

Road Safety Commissioner Kim Papalia would not say if he supported the trial but he urged drivers to “only overtake when you know it is safe to do so”.

Police Minister Michelle Roberts also declined to comment.

A WA Police spokesman said the force did not support overtaking lanes being closed.

- The Sunday Times