Posts Tagged safety

Most of your body is not protected by a bicycle helmet

This was a comment on, but they never published it and then closed comments.

First off, I’m really sorry to hear you had such a terrible accident, and I’m very glad to hear you’ve managed to recover from it. Please don’t misunderstand me on that, in what I’m about to write.

I have to say, it sounds like you suffered quite a number of very serious and potentially life-changing, even life-threatening, injuries across your body – the spinal injury in particular. The recovery time and process for several of these injuries would have made quite an impact on your life. The important thing to note is these are injuries for which a helmet gives no protection. To think that the major lesson to take away from your accident is “wear a helmet” is, I’m sorry, dangerous. The real lesson is:

Helmets are not magic and will not protect you from major injury, even death, generally. If you want to be safe, slow down!

Indeed, it is actually possible that the helmet contributed to your accident and hence your injuries, by making you over-confident and taking more risks on a fast downhill descent than you might have if not wearing helmet . A well-known effect, called “risk compensation” or “risk homœostasis“.

I often don’t wear a helmet. I’ve had other cyclists comment on this, and question why I dare to take such a risk. Then I see these same cyclists fly past on downhill descents, barrelling through corners and taking far more risk than I would. They are surely far more likely to have an accident because of this, and their skin, limbs, torso, major organs and face are no more protected than mine are! Further, there is clear evidence that helmets, while helping protect the cranium (but to a lesser extent than is often thought), increase other injuries. Particularly neck and facial injuries.

So, again, I am baffled that the life lesson you drew from your accident was that helmets are uber-important. The real lesson surely should be “Slow down! Take less risk!“. In the unfortunate event of a crash, the lower the speed, the better the outcome!

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Letter to Biffa about close pass

Sent over a month ago, on the 19th of  February. No reply from Biffa to date.

Yesterday morning, at about 0910, I was cycling along Archerhill Road, in the West End of Glasgow. As I came to a constriction in the road (parked cars on my side, road works on the other side), one of your Biffa garbage disposal trucks decided to pass me. Given the constriction, they had to pass very close to me – far too close. I don’t believe there was any maliciousness on the part of the driver. I just don’t think they realised what they were doing.

I’d be very grateful if you could issue a reminder to your drivers about rule 163 of the Highway Code, and that cyclists need to be given as much clearance when passing as they are tall. This is needed in case something happens that makes them fall to their side (such as unexpected potholes, parked cars opening doors, mechanical failures, etc), to ensure they are not seriously injured by passing vehicles.

I’m sure you’re as anxious as I am that your drivers are mindful of the safety of more vulnerable road users. I look forward your reply.


Paul Jakma.

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McGill’s buses and yellow lights

Below sent to McGill’s buses a few weeks ago, via their website.

Dear McGill’s,

Please could you remind your drivers that a yellow light means “Stop, unless doing so would cause a collision”. It does NOT mean “Speed up and get through the lights!”.

I go through the junction at the north side of the Finnieston bridge, and I regularly see your bus drivers going through red there, because they didn’t heed yellow. On some occasions, as they turn right, they actually go through the pedestrian lights that have already gone green! There is simply no excuse for this, as they would have had a yellow for several seconds.

Please re-iterate to your drivers that yellow means “Stop, unless unsafe to do so”.


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The case against bicycle helmet advocacy: a quick guide

Bicycle helmets are tested with vertical drops from a maximum height of about 3m onto flat surfaces (BS/EN 1078:1997). In such testing, helmets definitely help. However, the scientific evidence on helmets & population wide injury rates is far from clear that helmets actually are beneficial.

While amongst cyclists who suffer injury, helmets of themselves do reduce head injuries significantly, they also increase neck and facial injuries, so that there appears to be negligible benefit overall (Accident Analysis & Prevention: … meta-analysis of bicycle helmet efficacy). Study of bicycle injury rates in Australia around the time of introduction of mandatory helmet laws suggests that, though there is a noticeable dip in injury rates around the introduction of the law itself (not necessarily attributable to the helmet itself in my opinion) that injury rates then started increasing again, to the point rates were nearly the same at the end of the study period as before the helmet law, and trending to surpass it! (My Blog: study-shows-australian-cyclist-helmet-law-leads-to-increasing-head-injury-rates). Helmet use also appears to induce risk-compensation behaviour in motor vehicle drivers – they make closer passes (Accident Analysis & Prevention: Drivers overtaking bicyclists…). No doubt the cyclists themselves also are subject to risk compensation. Thus, by wearing a helmet there may be an increased risk of getting into an accident.

There may be further population wide psychological effects caused by a culture of “Must be wearing a helmet to be safe!”. It is sending the message that cycling needs safety equipment, and hence must be dangerous, which surely will put off many – certainly where mandatory helmet use laws are introduced rates of cycling then significantly decrease. The reverse is of course true: the overall health benefits of cycling greatly outweigh the quite tiny risks – risks which are not greatly changed by helmet wearing, the studies appear to say. In other words, by advocating helmet use, one may be harming the rates of cycling by sending the wrong message on safety, and hence harming public health overall.

Further, as cyclist safety on the roads correlates strongly with rates of cycling – more cyclists leads to more awareness & safer roads, and similarly fewer cyclists means less safe roads – this means a culture of helmet use may well lead to increased injury rates amongst cyclists (in addition to the general adverse public health effects of fewer people cycling). This would be very hard to categorically prove or disprove in causal terms, however the Australian experience certainly suggests a correlation, as I think would a comparison of the UK and Netherlands.

Finally, in the Netherlands, one of the safest places for cycling in the world, cyclists almost universally do not wear helmets, including very young cyclists. Thus, we can be quite certain that helmet usage is not a pre-requisite for safe cycling. Indeed, it is in places like the UK and USA, with some of the worst cycling safety in the developed world, where the focus on safety equipment for the cyclist seems to be greatest.

In short, the focus needs to be on those things around the cyclist (e.g. default legal liability to influence motorists’ behaviour, safer road infrastructure, etc) – not what is on cyclists. Focusing on cyclist safety equipment to me seems futile at best, and perhaps even detrimental to the cause of mass, safe cycling, if that’s a cause you believe worthwhile.

NB: Helmet use should always be a personal choice. The issue is complex, the trade-offs may differ greatly in different scenarios – helmets may be very beneficial in some settings, e.g. some kinds of racing. The choice should be your own. However, general advocacy of cycling helmets seems inappropriate and probably harmful, to me.

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Reducing car/cyclist conflict: Dutch v Glasgow Style

Recently I sent a letter to GCC with some complaints about NCR75. To their credit, they appear to have acted on at least some of that letter (with thanks to Alison Thewliss for raising my letter with GCC LES) – they seem to clean the previously glass-strewn path a lot more often now, and they may have put up more signs to show which paths are meant to be shared-use.

However, regarding the Clydeport car-park entrance on the Broomielaw and how it interrupts and inconveniences the national cycle route that crosses its entrance with a dropped kerb, their response was:

At the Broomielaw, National Cycle Route 75 is located on the north side of the Casino, using a shared use pedestrian/ cycle track. Drivers exiting the Clydeport car park have poor sightlines, hence the kerbs nearest the wall on the cycle track have not been dropped, thus encouraging cyclists to stay away from this area, where they are harder to see.

Now, bear in mind this is an almost unused car-park – I’ve never seen a car going in or out there, even though I commute past there every morning and evening. The cycle-path there on the other hand is heavily used. Further, the kerb, though lower toward the outside, is still a raised kerb and an impediment to cycling! Never mind the road surface is also broken up to at least one side.

So the message is, when it comes down to the convenience of a large number of cyclists, versus that of a property holding company and its under-utilised, city centre car park for a couple of employees, well the cyclists can more or less go and get stuffed.

Update: Went past the Clydeport car-park later in the day today and it does seem full.

Entrance to the Clydeport car-park on the Broomielaw, with the National Cycle Route 75 crossing it. The cycle-path has a dropped kerb, very inconvenient for cyclists, particularly any carrying luggarge, and any on normal, non-offroad bikes. Note the cyclists having to stand up to negotiate the kerbs, even though they are out from entrance. Still looks like urban mountain-biking, sadly.

Another view of the car park entrance. Note that cars actually have plenty of visibility to this direction. It is only the wall on the other side that is impeding visibility. Note also the broken surface of the road, making the far kerb even harder to negotiate.

It is actually quite possible to engineer minor side-streets and entrances that must cross cycle-paths so that cyclists progress and safety is not  compromised. They manage it all the time in the Netherlands. The line-of-sight issue could be better resolved by modifying the wall, and/or installing a lowish, progressive projection/kerb around the entrance wall to ensure cyclists move further out (indeed, this would be a good idea either way). Further, it should be Clydeports’ responsibility to ensure that its property does not impose undue risks on the passing public. At least, I would hope there is legislation and/or by-laws in place, to that effect.

So how do the dutch do it?

Dutch cycle-lane, with a minor-side-street junction. The junction is engineered to safely allow cyclists on the busier street the right of way over the quieter joining entrances. Note the conspicuous signage to remind drivers of the cycle lane, and note the concrete segregation barriers immediately before the junction, to prevent car drivers from turning in fast and early.

Note how the road is further engineered to slow down any cars before they cross the cycle lane, and so reduce conflicts. The cycle lane is raised up slightly with a smooth gradient, while the roads have a steeper kerb to negotiate, to force them to slow down and further help make them aware of the cycle lane.

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Guest Blog: A Pilot’s View on Banner-Towing

Another guest blog from retired pilot Rudy Jakma. This on the topic of banner towing – where light-aircraft trail a banner behind them, to be read by people on the ground. Rudy has extensive experience of banner-towing, particularly from the earlier parts of his career, with around 4000 hours logged, and around 1000 banner pick-ups. His experience even pre-dates his flying career, as he worked as a 16-year old at a local aerodrome, helping to prepare banners to be picked up.

Last week, during the election campaign in the UK, a light aircraft crashed injuring the pilot and his passenger. It had been involved in a banner-towing flight on behalf of a political party, and the passenger, Nigel Farage, was an official of that party and standing as a candidate.

On Sky News, an “expert” proclaimed that towing a banner would have put the aircraft under abnormally high stress, increased by the weight of the passenger and that this would have meant that the flight (which sounded as if he meant the entire flight) was more hazardous due to the presence of the banner. Where do they get these experts from?

From the TV footage of the wreckage I identify the aircraft as a Polish-built Wilga. This is a purpose-built utility aircraft. Towing objects, be they banners or gliders, is well within its structural capability.

All aircraft used for towing must be approved according to manufacturers’s recommendation and are fitted with quick-release tow hooks. The aviation authorities will follow manufacturers’ guidelines and may impose further limitations before they approve a certain aircraft type for towing operations. This ensures that towing an object will never allow stresses to be imposed on the structure that could compromise the structure in any way, be it due to deformation, stress or metal fatigue. The limitations will be published in the aircraft operating manuals and, if deemed necessary, also posted on placards in the cockpit.

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Guest Blog: Pilot’s View on the Volcanic Air Travel Disruption

A topical guest blog entry from Rudy Jakma, a recently retired commercial pilot, with 22,000 hours of experience on a wide range of aircraft, many of them on jets.

For four days air ravel all across Europe has been severely disrupted by clouds of ash from a volcanic eruption in Iceland. A stable area of high pressure steered the ash clouds first towards the British Isles. Then it drifted slowly towards the north of continental Europe where is lingers. Continued volcanic activities are feeding the cloud which so far has showed but little sign of dispersing.

The problem is that very little is known about the effects of volcanic ash on aircraft. Only a few have resulted in recorded incidents, the best known the case where a British Airways Boeing 747, commanded by Capt. Eric Moody, without warning flew into the ash cloud of a volcanic eruption of the Krakatau and lost power of all 4 engines. It resulted in a celebrated triumph of excellent crew management and airmanship. Three engines were evenutally restarted. The aircraft landed safely but was severely damaged.  It is my guess that many aircraft, before and since, may well have flown through the residue of a volcanic eruption without ever being aware of it.

The problem facing Civil Aviation Authorities and airlines is that there are little or no statistical or scientific data available on the effect of volcanic ash on aircraft – other than the few cases that resulted in incidents. These incidents demonstrated beyond a shadow of doubt that volcanic ash can pose a severe potential hazard to aviation. These are the worst-case scenarios. The dividing line between acute danger and a minor risk is anybody’s guess. This is the reason why the authorities see no choice but to err on the side of safety.

The majority of aircraft  used by the airlines to-day are equipped with jet engines. They are at their best effciency at higher altitudes. In general above 30,000 feet. This is where, according to reports, the ash cloud lingers. They fly at speeds of around 500 mph which turns the minuscule ash particles into sand blasting. It can damage every part of the aircraft facing the airstream: Wings, engines and windscreens.

Jet engines suck in enormous quantities of air. Part of which goes through the combustion chambers and part is bypassed around the engine to give a large volume of gases leaving the exhaust at high speed to propel the aircraft. The compressor at the front of the engines has a number of blades that have a critical aerodynamic shape. The ash particles can damage the compressor blades, altering their shape and making the engine less efficient. The ash going through the combustion chambers may melt and form a deposit on the turbine blades. The result will at best be a heavy repair bill, at worst a write-off of the engines. Perhaps even of the entire aircraft.

Even though this will probably not result in a crash, safety regulations prescribe that an airliner MUST be able to go around if conditions prevent a landing. If engine power is compromised, a go-around may be impossible. Damaged turbine blades may even result in so-called  “compressor stall” if full power is selected. This in turn could lead to a “flame-out” of the engines. Losing all engine power at a critical moment is too great a risk to even contemplate.

Aviation has built an excellent safety record. A lot is based on the principle of redundancy and alternatives. Knowingly flying into an area where abrasion damage could degrade aircraft performance to an unknown extend is unacceptable. This consideration in itself can make departure of an airline flight with passengers illegal.

There are good reasons why authorities have decided to close a large – and expanding – portion of European airspace closed. However, the effect is already wreaking havoc with travellers. Passengers are stranded, many others are faced with cancellation of their plans. Many have booked and pre-paid holidays. Train and ferry services are filled to capacity and have long waiting lists, especially cross Channel services and ferries across the Irish Sea.

The loss of revenue, combined with the cost of accommodating stranded passengers could result in the bankruptcy of several airlines if this situation continues much longer. The survivors could well become the dominant players when – to use a very corny joke – the dust has settled. The landscape may well be very different after aviation resumes – whenever that may be.

Airlines already work on a wafer-thin margin. Regular airlines will have to look after thousands of stranded passengers, They also employ a large number of ground staff.  An event like this does not feature in the business model of any airline. Budget airlines in general do not look after their passengers in the same manner. They also have in comparison a lot less overhead.

It will be interesting to see who will come out the winners. I do not think it is coincidental that Ryanair were the first airline to cancel all flights for a longer period than most other airlines. They immediately reduced their exposure to being obliged to look after their passengers. Having a much leaner payroll, it is my guess that Michael O’Leary made a calculated gamble and battened down the hatches early. The Irish government may not have a choice but to seek EU approval for Ryanair to take over Aer Lingus. If there will be anything left to take over!

There will be more victims, and survivors.

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