HIGHWAY patrol police say queuing up along a breakdown lane to turn left during heavy traffic is a "commonsense approach" to the problem.
Known intersections are the corner of Old Windsor Road and Celebration Drive in Bella Vista and the corner of Showground Road and Rowallan Avenue in Castle Hill.
Acting Senior Sergeant David Prevett, the senior highway patrol supervisor for the Hawkesbury Highway Patrol cluster (The Hills, Quakers Hill and Hawkesbury), said the alternative would be for cars to occupy the marked left lane, taking it out of action for most of the morning peak period.
"In essence it is an offence for vehicles to travel to the left of a continuous white edge line," he said.
"Whilst most of these vehicles would be doing this in breach of Rule 150 of the Road Rules, it is a commonsense approach."
Similar congestion occurs on the intersections of Windsor and Acres roads in Kellyville and Old Windsor and Sunnyholt roads, Glenwood, with drivers travelling at speed in the breakdown lane.
The greatest safety danger, Acting Senior Sergeant Prevett said, was when drivers crossed the edge line and passed stationary vehicles by driving down the breakdown lane at speed.
"It is these drivers that pose the greatest danger of impacting with another vehicle or cyclist," he said.
"Their actions are irresponsible and negligent and it is these drivers that are targeted by highway patrol officersas opposed to the drivers that are patiently waiting in a queue for a left turn."
The Roads and Maritime Services is investigating the roads in the area to determine future possible upgrades of Norwest Boulevard to reduce congestion and increase capacity.
It is also considering improving the roundabout intersection at Norwest Boulevard/Lexington and Elizabeth Macarthur Drive.