A new study on the impact of motorcycles on central London bus lanes has revealed evidence of a rise in accidents and conflicts at sites with a highly trafficked side road.

The Transport Research Laboratory (TRL) study examined data on motorcycle riders permitted to use eight bus lanes in the City of Westminster, comparing one year before and after the schemes were introduced.

It found the percentage of conflicts in bus lanes increased in line with the percentage of motorcycles using the bus lane, but the number of conflicts decreased on roads operating at less than half capacity.

The number of accidents increased on Baker Street, a site with a highly trafficked side road.

Accidents decreased on the whole of Haymarket, where motorcycle use had increased significantly, but the number of conflicts increased near a bus stop, and nearly all conflicts occurred in the bus lane.

TRL concluded that ‘caution should be used in allowing motorcycles into the bus lane under such circumstances’.

TRL stressed that the overall accident analysis was inconclusive, but raised some issues of concern, including worries over cyclist and pedestrian safety.

Bus journey times were found to have increased slightly in the after-survey. On Bayswater Road buses took an extra four seconds to travel between the two timing points after motorcycles were permitted in the bus lane.

This was attributed to the increases in the number of motorcycles using the bus lane, from 17 to 40%. The study concluded that there ‘were limited advantages in motorcyclists using some of the bus lanes under the observed conditions’.

The Mayor of London, Boris Johnson, has asked Transport for London to bring forward plans to allow motorcyclists in bus lanes. His predecessor, Ken Livingstone, has previously opted not to change the rules after a TfL study showed ‘no clear evidence of safety benefits to motorcyclists and potential disbenefits to pedestrians and cyclists’.