A study of bus lanes in Auckland(external link) investigated whether the introduction of bus lanes changed or created new types of hazards for cyclist and motorcyclists. Of particular interest was the effect of turning vehicles ‘let through’ by drivers queuing in the opposing lane.

Drivers of these turning vehicles have reduced visibility of the bus lane due to the opposing queued traffic and could pose a risk to cyclists and motorcyclists in the adjacent bus/cycle lane.

The study found that found that at three of the four sites bus lanes had no discernible increase in crashes after implementation but at the Dominion Road site an increase was recorded.

All of the sites experienced a reduction or ‘effective reduction’ (based on increased traffic/cyclist volumes) in crashes except for Dominion Road which had a 30% increase in crashes. It should be noted that these crashes include both cyclists and motorcyclists.

The study concluded that there was a link between bus lane width and crash rates, as Dominion Road was the narrowest bus lane (3.0m) the other three bus lanes were 3.25m, 3.25m and 4.5m wide.