Wednesday, 16 June 2010

Bus Lane Trial Should End Now

Boris' scheme to put motorbikes into bus lanes was always ill-conceived. Today's data from the first trial period shows its downright dangerous for many road users. He should swallow his pride and scrap the extension of the trial now before more people get hurt unnecessarily.

Remember this? At the time Boris's rather grumpy remarks were ascribed to the fact that he'd been held up by protesters in Trafalgar Square. With hindsight might there have been an additional cause for his displeasure? Namely that bikers behaviour in bus lanes had come perilously close to scuppering one of the few manifesto promises he's managed to keep. As it is TfL have had to 'fess up today that putting powered two-wheelers into bus lanes has increased accidents by a considerable margin. You'd think that ought to be enough to have the trial scrapped. Not a bit of it. No-one outdoes the current Mayor on stubbornness and he's not about to change his ways now. Through TfL Boris announced an extension of the trial claiming:
...the initial trial has shown some positive results

From the data presented, I fail to see what these could possibly be. There are two main areas for concern. TfL commissioned detailed research from the Transport Research Laboratory (TRL) to determine if safety, amongst other things, had been affected by the change. This report compared sites where motorbikes were allowed in bus lanes with areas where they were not. The results for motorbike safety are pretty clear. For cyclists the conclusions leave something to be desired in my view.

Firstly, collisions of motorcycles with other road users have increased. The report produced concludes clearly that there is statistically significant increase in collisions involving motorbikes where they have been allowed access to bus lanes compared to where they have not been.

Secondly, collisions involving cyclists have also increased (again by a statistically significant margin) in those bus lanes where motorbikes have been allowed. Unfortunately, however here the report gets a bit hazy. It suggests that an analysis of the particular mode of collisions indicates that the presence of motorbikes is not the cause of the increase, and that an increase in cycle flow will "partially" explain the increase. There are a number of problems with this analysis as far as I can see. The report itself identifies that this analysis depends on a subjective assessment by a traffic officer of the cause of a particular collision. You have therefore introduced opinion into your (up-to-now) strictly factual analysis of collision data. It also relies on the the traffic officer giving the cyclist a fair-go. I would not impune the professionalism of our police in London, but I am not sure they always understand the difficulties that cyclists have navigating the city.
Perhaps more substantially the report presents no firm conclusion as to why the accident rate did increase beyond a partial explanation. To my mind that should indicate that you know there's an increase but you don't know why. Consider this for example, the reports suggests most collisions involving cyclist were as a results of poor observation (i.e. I didn't see the bike, car etc.). Is it possible that a general increase in traffic in bus lanes with bikes zipping past you at 30MPH has made situational awareness a more difficult task for cyclists. Intuitively, as a cyclist myself I think it has. Has it made it more likely I will have an accident with something other than a motorbike? I have no way of knowing and importantly neither do the authors of the report. The assertion therefore that the increase is not connected with the presence of motorbikes is flawed in my view. There's either a real impact on cyclists from motorbikes by a mechanism that has not been considered, or alternatively there's a significant confounding variable that makes comparisons between the test and control sites unreliable generally.

Either of these changes in road safety should have meant the trial wasn't extended. Why? Well imagine if Boris' had introduced the initial trial run as follows:

I am going to allow motorbikes into bus lanes. I am aware that this will impact their safety and will produce more road accidents and injuries. In addition there will be more collisions involving cyclists, some of whom will also be injured. I will pretend I understand why, by some mechanism not fully explained, collisions with cyclists increase and insist it is nothing to do with the motorbikes. In reality I will be clueless.

Gentlemen, please start your engines!

Sadly that is exactly what he effectively said to us today. It would have been nice for him to be interviewed perhaps on why he thinks the extension is a good idea. Sadly he doesn't seem to be around:

@mayoroflondon: By the spectator zone at the Cape Town Waterfront

Nice life isn't it?

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