Painted bike lanes are not the best solution for keeping riders safe because motorists tend to pass closer to them, research has revealed.

Cycle lanes that are not physically separated from other traffic significantly reduce the distance motorists provide because drivers do not feel the need to give cyclists space when they have their own lane, the authors believe.

The research, published in the journal Accident Analysis and Prevention, found that drivers on roads with a bike lane and no parked cars passed 27 cm closer to the cyclist on average.

On roads with a cycle lane and parked cars they passed 40 cm closer, on average.

The data was collected on 60 cyclists in Melbourne who made over 400 trips with a custom device containing GPS and ultrasonic sensors to detect the distance that drivers provided when passing.

The median passing distance was 1.73 metres and six per cent were closer than a metre.

Overall, one in 17 passing vehicles came within one metre of the cyclist and there were nearly two passes closer than a metre for every 10km travelled.

In Britain, drivers can be fined £100 and given three points on their licence if they fail to give cyclists at least 1.5 metres of space when passing.