West Australian drivers must leave a minimum safe passing gap for cyclists or risk fines and the loss of demerit points in a trial of new laws.
The new rules, which came into effect on Thursday, require drivers passing a cyclist travelling in the same direction to keep a minimum distance of one metre when the speed limit is 60km/h or less and 1.5 metres when it is higher than 60km/h.
The penalty for breaking the law is a $400 fine and four demerit points.
Drivers are also permitted to cross centre lane markings on roads, including double white lines, to ensure the appropriate passing distance.
The two-year trial will be monitored by the Road Safety Commission, which will evaluate its success in a report to be delivered to Road Safety Minister Michelle Roberts.
She said it was hoped the law will lead to a greater mutual respect between motorists and cyclists.
"Cyclists are among our most vulnerable road users, and tragically we have lost seven West Australians in cycling crashes already this year," she said.
The law brings WA in line with minimum passing rules in Queensland, ACT, NSW, South Australia and Tasmania.