Three Perth cyclists saw their lives flash before their eyes last week when a road train came within centimetres of their bikes.

Virginia Sergas was training with her two friends on Canning Road in Kalamunda on Thursday when a road train overtook them.

“We were riding in a line and a big truck came really close to us,” Ms Sergas, 31, said.

“When you are on a bike you really get blown around and sucked by the air - you really feel it.”

Ms Sergas, a personal trainer, did all she could to keep her bike still.

“If I fell it could have been really bad,” she said.

WA’s one metre rule, which stipulates vehicles need to give cyclists at least one metre space in a 60km/h zone and 1.5m at above 60km/h, came into effect in WA on November 30.

The penalty for breaching the rule is a $400 fine and four demerit points, which means this driver could potentially lose eight demerit points.

At least one driver has been fined under the new rule since it was introduced, for a close pass in Carramar earlier this month.

Ms Sergas, who is pictured in the footage from her friend’s rear camera, said close passes happened quite often.

“Most drivers leave enough space but some don’t - I go out three to four times a week and close passes happen about half of those times,” she said.

“People in cars need to understand that we are on a bike so is anything happens we are the ones who are going to end up bad.”

She said she would ride on Canning Road again but close passes would always be in the back of her mind.

“Whenever I go out I am always very careful but I always keep it in mind that some people don’t pay attention or think about cyclists,” she said.

The cyclists have not yet taken the footage to police.