Monday 19 August 2013

Blind-spot crashes

Cycling is promoted in the built-up area because of the positive effect it has on the environment, traffic flow and personal health. However, cyclists account for about a quarter of all the road fatalities and more than half of all the serious injuries. Over the last ten years, statistics show that the reduction in fatalities amongst cyclists remains behind that of other road user groups. Their safety therefore requires serious attention and action.

Sound familiar? But this is how the Dutch Institute for Road Safety Research (SWOV) regard the situation in the Netherlands today. My reason for mentioning it is to make plain that improving the safety of the cycling environment in the UK is going to need a long-term commitment, a very long-term commitment indeed.

In 2009, in the Netherlands, 185 cyclists were killed in traffic, ten by right-turning trucks. Typically, these blind-spot crashes occur at junctions in towns and cities, when a lorry wants to turn right (moving from stationary), and a cyclist riding to the right of the vehicle—or positioned diagonally in front of it—wants to go straight ahead. This frequently happens at junctions with traffic lights where cyclists get the green light simultaneously with other traffic (Figure A).

In principle cyclists have the right of way in this situation, but it sometimes happens that they are not seen by the driver. For their part, cyclists are often unaware that the lorry driver is unable to see them, or that the driver wants to make a right-turn. Thus, cyclists tend to assume the right of way without first ensuring they have actually been given it.

In a study carried out between 2006-7, it was shown that 98% of the incidents which took place between right-turning lorries and cyclists involved vehicles with a high windscreen (higher than 1.5 metres). These vehicles accounted for about 70% of the heavy road traffic, incidentally.

To briefly summarise, the three main causes of blind-spot crashes are as follows:
• The visual field of lorries is insufficient;
• Truck drivers do not make the best possible use of the different mirrors that are available to them, and / or these mirrors are not adjusted correctly; and
• Cyclists insufficiently take account of the fact that trucks have a limited field of view.
As much as possible, the aim must be to keep cyclists apart from heavy traffic. According to an oft-quoted report, "In SWOV’s opinion, the ultimate solution for the blind-spot problem is a structural separation of trucks and cyclists. How this must be organised, and what the economic consequences will be, requires further study. For the time being, the solution can be found in separating cyclists and trucks at intersections, both in time and position. Furthermore, it is important to make both the truck driver and the cyclist more aware of the hazards."

The "ultimate solution" SWOV have in mind actually goes much further than one might initially suppose. As you would expect, the Dutch already have a very good idea how to organise cycleways, and the economic consequences of installing them are also presumably well established, so it is hardly the case that these would require much in the way of further study. No, what is being suggested here is that heavy lorries should be denied access to cities, towns and villages. This would make it necessary to construct distribution centres outside of urban areas, of course.

Such a measure may seem far-reaching, but in fact it fits in with the Strategic Road Safety Plan (Ministry of Transport, 2009), so it is clearly not far-fetched. Even so, it goes without saying that such an idea cannot easily be implemented. Research is required to make clear the pros and cons of all the different possible solutions.

For example, other ways to separate the different types of traffic would be to shift the times in which freight traffic is allowed access to urban areas (Mesken & Schoon, 2011), and to restrict the number of routes available to freight traffic (Schoon, Doumen & De Bruin, 2008).

Short-term solutions

SWOV say: "Because blind-spot crashes appear to be avoidable, and because the consequences for the casualties are often very severe, this type of crash attracts considerable media attention." But what can be done about it?

In the short term, dangerous junctions could be adapted. This can be done by installing advanced stop lines. Where necessary, cyclists can be given a separate green light, or else research from Denmark suggests that the 'bike box' should be at least five metres deep (so that lorry drivers have a direct view of any cyclists who may be waiting ahead of them).

ASLs theoretically allow cyclists to play to their strengths by normalising their practice of filtering to the head of queuing traffic during the red phase at traffic lights. Cyclists turning to the offside are able to take up a proper turning position, and straight-on cyclists can adopt and maintain a prominent position for transiting the junction safely within the main traffic stream. An ASL also helps to reduce the exposure of cyclists at junctions with nearside filter lanes by providing a place for cyclists to wait while traffic passes on the inside.

At a red light, cyclists are more visible to motorists by being in front of them. At a green light, the presence of an ASL reminds motorists to watch out for cyclists.

That's the theory, at least. Advice produced by RoSPA regarding cyclists and lorries cautions cyclists that even when a junction has an ASL, it may be better to hang back if there is a lorry present.

The bottom-line, according to a publication entitled Promotion of Cycling, is that it is vital that cyclists are visible to motorists at junctions, and also that cyclists are aware of cars.

Stressing that I am talking here about short-term solutions, another measure—which is linked to a different aspect of good cycle provision—is to make alternative cycle routes more numerous, more comfortable, easier to follow, and more convenient (by removing annoyances for cyclists, for example).

Various pictures of Cambridge by Jme (Keep Pushing Those Pedals)

As Jim from (Drawing) Rings Around The World pointed out in a recent blog entitled 'The road not taken': "I recently changed the route of my cycle commute into central London, trading a longer journey (about five minutes more) for a cleaner, safer and less stressful one. [...] Cyclists make these kinds of calculation all the time. They take quiet back streets to avoid dangerous main roads, they dismount and cross at pedestrian signals rather than try to turn right across moving traffic, and so on. There are a number of daredevils who take the most direct route to where they're going regardless of the conditions, but in my experience almost everyone who cycles accepts some kind of delay or diversion in exchange for extra safety, comfort or peace of mind."

Another measure is to increase the lorry driver’s awareness of his immediate surroundings. In the last five or six years, EU laws on mirrors have been most important in this regard. More recently still, several ‘intelligent’ blind-spot detection and warning systems have been developed. However, the practical difficulties of applying such systems are yet to be resolved (Connekt, 2010).

A system that warns the lorry driver of a cyclist in the blind-spot is possible. However, the challenge for such a system is in the timing: too soon and the driver is confronted with false alarms which he will eventually ignore; too late and there is insufficient time to react (Hoedemaeker et al., 2010).

A system that warns the cyclist, rather than the driver, is not desirable, as the cyclist has the right of way, and the driver cannot predict what the cyclist will do with the information. Moreover, the situation remains unclear for as long as such a system is not installed in all lorries. No signal could either mean that the lorry continues to go straight on, or that the lorry is not equipped with such a system.

The fact that cyclists are often unaware that a lorry intends to turn right (Schoon, Doumen & De Bruin, 2008) could be due to the fact that the indicators are often placed too far to the rear, and are therefore not visible to cyclists. Several indicators placed along the side of the cab would help to ameliorate this, though it must be emphasised that the arguments against made in the previous paragraph would still hold true.

A non-solution

Following the death of Phillipine de Gerin-Ricard, the Mayor of London, Boris Johnson, told the BBC: "The thing that makes cycling safe in London is when people have the confidence to do it in numbers. The more you can get on the roads, the safer it is going to be for everybody."

Fred Wegman, the Managing Director of SWOV, has written about Safety in Numbers. Herefollows an extract:

"The risk to a single cyclist is greater than the risk to a cyclist who is part of a group. The American researcher Jacobsen compared the casualties amongst cyclists in different countries, and tried to establish a relation with the amount of bicycle traffic. He concluded: “Policies that increase the numbers of people bicycling appear to be an effective route to improving the safety of people bicycling”. In other words: add more cyclists to traffic and cyclist safety will increase.

"This is a popular idea among those who put effort into stimulating cycling and is therefore quoted frequently in these circles. However, I believe that this conclusion is not correct. I will try to explain why.

"If there is much cycling in a country, the risk for cyclists is indeed lower. Comparison of statistics of different countries offers conclusive evidence. The risks in countries that have a lot of cycling, like the Netherlands and Denmark, are (much) lower than in countries where cycling is a less important mode of transport. The explanation may be twofold. Firstly, there are the expectations of the other road user. If a driver does indeed expect a cyclist on the road, as is the case in the Netherlands and Denmark, the risk is lower. But a second explanation is conceivable: if there are more cyclists, safer cycling facilities will be constructed (which in turn makes cycling more pleasant).

"We have sufficient evidence that cycling facilities (like bicycle tracks) reduce the risks of cycling. Not only do the Netherlands and Denmark have a lot of cyclists, they also have a lot of cycling facilities. I do not expect that a greater number of cyclists would, on its own, result in a reduction of the risks faced by cyclists. On the other hand, I do expect that the development of more cycling facilities would lead to lower risks. Policy that focuses only on an increase in cycling—and at the same time ignores the construction of more cycling facilities—will not have a positive effect on road safety."

The 'only' solution

Mike Cavenett at the London Cycling Campaign recently wrote an article published on The Guardian blog which was entitled 'It's time for cyclists to make a stand over safety'. He said: "We believe that high-quality Dutch-style segregated tracks, along with cyclist-specific traffic lights to remove conflicts, are the only way to truly protect cyclists on the busiest streets."

Mike doesn't reference this point, but that's fair enough, because everyone is entitled to their own opinions. However, people are not entitled to their own facts, and the case is that these high-engineered solutions are not the only way to protect cyclists on the busiest streets, and nor are they even the best way to truly protect cyclists on the busiest streets.

I deplore this way of thinking, because there are reasonable solutions which the authorities should have taken years ago, and which they certainly should be taking now, but which they are held back from doing—let's be generous—because of ideological considerations.

I am looking for something much better than this from an organisation which purports to be the voice of cyclists in London. I am looking for them to:
• recognise the problems;
• find workable means to solve these problems; 
• understand the importance of prioritisation and order of precedence; 
• gather together all relevant information;
• interpret the data, appraise the evidence and evaluate the arguments; 
• use language with accuracy, clarity, and discernment; and
• draw warranted conclusions and generalisations.
Critical thinking, in other words. Instead of which, they present us with an idea which obviously has its merits—though it is assuredly difficult to deliver—but at the same time, they stand in opposition to a solution which is regarded as "a prudent course to follow", simply because one part of it is, by necessity, far from perfect.

According to Wikipedia, "It is common for arguments which commit this fallacy to omit any specifics about exactly how, or how badly, a proposed solution is claimed to fall short of acceptability, expressing the rejection in vague terms only."

Thus, we hear from the LCC that a comprehensive, city-wide cycle network introduced to a minimum level of functioning would do NOTHING to improve the safety of cyclists. But that's about the extent of their criticism. It wouldn't make any difference, they claim: need they say more?

The Cycle Network and Route Planning Guide published by the Land Transport Safety Authority of New Zealand says on page 31 that cycling through a junction on the roadway is generally safer than from a path. Unfortunately, they don't reference this point either, and as far as I have been able to establish from Google, this is an argument which is almost exclusively propounded by vehicular cyclists.

I have taken on board the arguments laid down in a wiki article published by the Cycling Embassy, which counters claims that cycle paths are dangerous where they cross junctions. (In the case of Figures B and C above, it is sometimes the case that drivers fail to appreciate that the cycleways are two-way, and are therefore not looking out for cyclists approaching the junction from the other direction.) Even so, the fact remains, to quote Cycling: the way ahead: "Reproducing apparently effective action taken elsewhere could have negative consequences if the concerted and coherent programme on which such actions were based is not taken into account."

Understanding the importance of prioritisation and order of precedence

If the LCC's primary concern is to improve the safety of existing cyclists—as much as possible, I mean, and as quickly as possible—if it isn't, then why not?—they shouldn't solely be focusing on a strategy which is unlikely to deliver any significant benefits until the medium-term at the absolute earliest.

I am specifically not saying that developing parts of the network shouldn't be done to the highest standards. Furthermore, it is absolutely right that people should continue to speak out for best practice, and offer constructive criticism where necessary. But a demand for good quality infrastructure is one thing, and one thing only, and ought not to be allowed to hinder the "introduction" of the whole of the network.

As Danny Williams from Cyclists in the City has recently made clear: "You need to invest and you need to sustain investment, not just do a bit here and there when it pleases you." I very much hope it goes without saying that this programme of sustained investment would be most effective within the framework provided by a functioning cycle network.

If the LCC's primary concern is to increase the number of people who cycle—if it is, then why?—there is a significant number of potential cyclists—perhaps around 7% of the population—who are very likely to respond well to a 'network first' approach.

With a few notable exceptions, the cycling population of most UK towns and cities is about 2-3%. Something approaching 1% of these belong to a group identified as The Strong and Fearless (they cycle regardless of the road conditions). In London, the Mayor has set a target to deliver a 5% mode share for cycling by 2026. Reaching this target should be as easy as winking, and this done, and with a functioning cycle network in place, we would then be in a much stronger position to kick on around the final bend, so to speak, and make our way confidently down the home stretch. This is not what the LCC have in mind, however. They expect us to be able to turn up on the day of the race, as it were, fat and wheezing from years and years of inactivity, and then, like some modern-day Hippomenes, deceive their one true love into embracing them by throwing three golden apples into her path.

So much of good cycle advocacy, it must be said, is about the pursuit of authenticity, immediacy and honesty. It has very little, if anything, to do with easy answers to difficult questions.

The real reason for cycleways

In a timely article written on the Green Lane Project blog, Michael Andersen asks: "What if bike designers, instead of arguing about safety—an argument that, to be clear, I think protected bike lanes would win—decided that the most important measure of a good bikeway is whether people tend to like it?"

He continues: "I'm not arguing that safety is unimportant. [...] But when professionals make safety their only absolute value, they presume that physical safety is the most important value in people's lives. And that assumption is demonstrably false. Of course people want safety. But they want other things, too."

The Mayor's Vision for Cycling in London says that only one cycle journey in every 328,000 ended in serious injury in 2011, and the odds of being killed were 11 million to one. "On a strict average, you would have to cycle in London every day for 900 years to come to serious harm."

Even so, as Rachel Aldred points out: "Disproportionate injury risks are a social justice issue: London cyclists face a 30 times higher KSI (killed & seriously injured) risk per km than car travellers (the Dutch ratio is 4:1)."

To be fair, the Mayor's Vision acknowledges that fear of injury is the number one reason why Londoners do not cycle. It is clearly not enough, the Vision also recognises, that cycling is statistically safe; it must also be perceived to be subjectively safe.

Anyway, engendering a feeling of subjective safety is the reason why, at the Green Lane Project, they use the phrase 'low-stress' to describe the bike networks they value most. They don't talk about building 'safer bike lanes', though ultimately, of course, a good network would make cycling safer. They simply talk about building 'better bike lanes'.

"People aren't robots," Michael points out, "and they don't change their behaviour based on mathematics. They change their behaviour based on feelings."


"Collisions between right-turning lorries and cyclists continue to happen, despite various measures to enlarge the lorry driver’s field of vision, and despite efforts to increase the awareness of cyclists by means of public information campaigns. The number of crashes of this kind could be reduced by creating a separate infrastructure for lorriesHowever, this far-reaching measure still requires research.

"In the meantime it will be necessary to reduce the number of crashes by other means, such as infrastructural measures at junctions and a permanent public information campaign about a code of behaviour for cyclists. Other possible new developments for reducing the number of blind-spot crashes include technical facilities to aid the lorry driver."

The information in this article is largely based on two SWOV factsheets: The Way to Safer Cycling and Blind-spot crashes.

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