Airbags expanding

[The Spin Doctor]

If you T-bone the passenger compartment of a car it's highly likely that your head will impact. No fast or slow airjacket will help much, not even aided by a packet of paracetamol.

As demonstrated by a couple of the videos that are supposed to show the speed at which the jacket inflates. We've been here before... quite a few times.

[Horse]

If you T-bone the passenger compartment of a car

been here before... quite a few times.

[X] Poor obs. You ought to expect those types of situation to develop

[Hot_Air]

It wasn't a single paper, but a systematic review. It concluded that:

"Due to the poor quality of studies identified, we were unable to draw any conclusions about the effectiveness of rider training on crash, injury, or offence rates. The findings suggest that mandatory pre-licence training may be an impediment to completing a motorcycle licensing process, possibly indirectly reducing crashes through a reduction in exposure. It is not clear if training (or what type) reduces the risk of crashes, injuries or offences in motorcyclists, and a best rider training practice can therefore not be recommended. As some type of rider training is likely to be necessary to teach motorcyclists to ride a motorcycle safely, rigorous research is needed."

See: Motorcycle rider training for preventing road traffic crashes

From this review, I don't think it's possible to say one way or another if advanced training in the UK has safety benefits. Context matters, not just the quality of studies. As ever, better research is required!

Both the TRL and Brunel University have done some research into the impact of advanced driving. The TRL study showed a 25% accident reduction for those who had passed an advanced car test, but it's not a recent study, and the Brunel study found improved judgement of speed and distance, as well as better car control. However, I think there's a dearth of research into the subject.

[Horse]

From this review, I don't think it's possible to say one way or another if advanced training in the UK has safety benefits.

What do you call 'training'? Does 'observing' qualify?
Does the training have generic criteria (learning intention, success criteria, etc.) for all trainees?
Is specific training designed for an individual excluded?
What is the purpose of the training? If to pass a test that has a specific set of requirements - e.g. 'making progress' - are they all safety-related?
How does 'advanced' differ from 'L'/test training and testing? Quantify those differences.

However, I think there's a dearth of research into the subject.

Not really, there's been loads. Just that they don't allow direct comparison between them and all have their own quirks. I won't say flaws because I'm not a scientist. One of the biggest, perhaps, is the ethical issues involved which mean that many of them have either been limited to self-selected participants or short-term / small-scale - crashes are fairly rare events.


FWIW, I could find and list umpteen studies that have looked at driver and rider training,

But:

"There is no scientific evidence in the literature in the form of scientific controlled studies that conventional fleet driver training is effective in reducing crashes (Keigan et al 1999 in Elvik et al 2004), despite the strong belief in the effectiveness of driver training courses by those involved (Hawarth et al 2000 in Elvik et al 2004). However, formal defensive driver training for professional drivers, taught at the workplace, combined in larger companies with motivation and incentive systems for crash-free driving, has been found to reduce the crash rate by around 20%. Other types of instruction for professional drivers, including skid training, both amongst ambulance drivers and drivers of lorries and articulated lorries have been found to increase the crash rate (Elvik et al 2004). It should be emphasised that these studies should not be interpreted as criticism towards training overall, but rather suggest that simple skill-based training schemes do not suffice."

Note: skill-based

A fair question that I've been asked when making similar comments and posts is "Well, if you saying training doesn't work, why do you bother?" My answer is that I think good training works.

As Spin points out, recently the term 'insight' training has been developed. Here's something from 2014:
http://www.advanceddrivers.com/wp-conte ... 2013-1.pdf

So to give you an insight (hah) into how I did skills training: One exercise that Born Again rides used to endure was a 'figure of 8'.

A couple of twists (sic):
- Sometimes more than one rider at a time
- Riding around obstacles (flower beds & trees) and it included a junction https://goo.gl/maps/26DRyb7oNAxs6rC49 (anticlockwise at the left end)
- Chance of traffic

So it wasn't simply a skills exercise, there was also:
- How to stop mid-bend
- Situational awareness
- Encountering and planning for other vehicles (including display team style crossovers)
- Dealing with obscured views

[Horse]

https://www.oshresearch.co.uk/2529407A8 ... review.pdf

In the fleet safety field, properly designed experiments are extremely rare; indeed, only one appears to have been published in a peer-reviewed journal. This was the study of Televerket, a Swedish telephone company, by Gregersen et al.,26 which Murray et al.20 have described as being ‘probably the most quoted – and misquoted – fleet safety study undertaken anywhere to date’. In this experiment, four interventions (driver training, group discussions, campaigns and bonuses for accident-free driving) were compared with a control group, and accident rates and costs were compared for a two-year period before and after the interventions. The results for the driver training group showed a statistically significant reduction of 40 per cent in accident rate after training. This is convincing evidence, but it should be borne in mind that the training procedures used in the study were far removed from those conventionally used by fleet trainers. There were three components to the one-day training programme in the Swedish study: low speed manoeuvring, skid training and commentary driving. These are described in more detail in a later paper by Gregersen,27 who comments that:

...the large accident reduction was unexpected. The most probable explanation is the purpose and content of the training. Specifically, the aim was not primarily to increase the driver’s skills in manoeuvring the car, but to create insight about risks in traffic and about the driver’s own
limitations’.

[Hot_Air]

Who needs an airbag to protect your cervical spine* (most of ’em don’t protect this area anyway)? So, I’m going to stick my neck out and share this video from those lovely people selling the Leatt brace.

Does anyone know what science - if any - exists regarding neck protection for motorcyclists?

[Horse]

Who needs an airbag to protect your cervical spine* (most of ’em don’t protect this area anyway)? So, I’m going to stick my neck out and share this video from those lovely people selling the Leatt brace.

Does anyone know what science - if any - exists regarding neck protection for motorcyclists?

In your thread on TRC I posted about the UCL research on computer simulation of head injuries which IIRC suggested that neck movement acts as an impact absorber. The implication being that, if you prevent head movement, the energy is absorbed elsewhere - potentially by the brain moving within the skull. And that's not always a good thing.

[Horse]

https://www.therevcounter.co.uk/threads ... ost2998870

We simulated three brain injury cases. These had very different head kinematics. Distinct patterns of brain deformation were predicted. The American football case involved a helmet-to-helmet impact. This resulted in acceleration pulses with smaller magnitudes but longer duration due to the compliance properties of both players. In contrast, the fall case involved head impact onto a rigid surface, resulting in head accelerations with larger magnitudes over a much shorter time. In the motorcycle accident, the helmeted head impact onto a rigid surface resulted in head accelerations with magnitudes similar to the American football impact but durations shorter than the American football impact and longer than the fall. The strains produced by head impact were largest in the American football case, which is consistent with previous studies demonstrating that acceleration pulses with longer duration generate larger strains within the brain (Margulies and Thibault, 1992; Kleiven, 2006). In contrast, strain rates were larger in the road traffic accident case and intermediate in the American football case. This might be related to the differences between the magnitude and duration of the acceleration pulse in these cases leading to variable responses of the brain due to its viscoelastic nature (Donnelly and Medige, 1997). The viscoelastic characteristic of neurons makes them more brittle when the rate of deformation increases, leading to their lower damage threshold to strain at higher strain rates (Elkin and Morrison, 2007; Tang-Schomer et al., 2010). Hence, high strain rates might produce more injury, and so our model results would predict that the road traffic and American football cases would be more likely to produce pathology in the sulci. This comparison indicates that nature of the initial head impact can have a significant influence on the pattern of brain injury parameters, which is likely to influence the likelihood of the development of long-term brain damage.

DTI provided converging evidence about the presence of persisting sulcal damage following TBI. DTI provides an estimate of axonal injury after TBI (Mac Donald et al., 2007) of the type that can be produced by strain applied to individual nerves. For example, strains applied dynamically to the optic nerve caused accumulation of neurofilament proteins in axons 3 days post-injury leading to the formation of axonal swellings and retraction bulbs, which are hallmarks of axonal injury produced after TBI (Bain and Meaney, 2000). Significant changes in white-matter integrity were observed at the boundary of the grey–white matter within the sulci but not the gyri relative to controls. Hence, the locations were tau pathology accumulates are both exposed to large strain and strain rate and also show persisting evidence of structural damage. Further work is needed to explore the specificity and sensitivity of this imaging approach in predicting outcome following TBI, but our results suggest that diffusion imaging might be used to assess structural abnormalities at the grey–white matter interface in possible cases of CTE. Advances in the diffusion imaging, including improved spatial resolution, should make it easier to assess the impact of TBI on small white matter tracts and improve the assessment of abnormalities present at the grey-white matter boundary.

We compared computational modelling predictions from a single fall, road traffic accident or sporting injury with neuroimaging results from a mix of different injury mechanisms. This is an informative comparison because CTE-type pathology is seen after injuries of different mechanisms and this is likely to reflect the underlying biomechanical forces produced at the time of injury, rather than distinct features specific to distinct injury mechanisms. CTE has most commonly been described in relation to repeated mild TBI, and has often been seen in a sporting context (McKee et al., 2009). However, there is little consensus about the frequency or severity of injuries that are required to produce CTE-type pathology. Smith et al. (2013) highlight that CTE-type pathology can be found years after just a single moderate-to-severe TBI. For example, in one neuropathological study 39 long-term survivors of single TBI were investigated (Johnson et al., 2012). Neurofibrillary tangles were exceptionally rare in the controls of this study, but were abundant and widespread in the around a third of TBI patients being commonly found in the depths of the sulci. This demonstrates that tau pathology is common after single TBI and is not confined to repetitive TBI. In addition, we have recently shown persistent amyloid pathology after a single TBI, which would be in keeping with CTE-type pathology present after single injuries (Scott et al., 2016). Therefore, understanding how the biomechanics of all types of TBI relate to CTE-type pathology is an important goal for TBI research broadly and not only repeated mild TBI.

Future work will be necessary to clarify the links between distinct biomechanical patterns of injury, brain pathology and clinical features of post-traumatic dementia. We have demonstrated that various types of injury can produce high mechanical strains in brain regions that show tau pathology in cases of CTE defined at post-mortem. However, it is currently not possible to define CTE clinically with confidence. Hence, it is unclear whether cognitive impairment in our TBI group is due to post-traumatic neurodegeneration or other factors such as the direct effects of the initial injury. This uncertainty limits our ability to determine whether the type of injuries we have modelled are likely to lead to clinical problems as a result of the neurodegenerative pathology. Relatedly, although the neuropathological literature suggests that a significant proportion of survivors of single TBI will develop tau pathology (Johnson et al., 2012), it is unclear how pathology at these locations relates to clinical features or to the chance of developing overt dementia. Some of these issues are likely to be clarified in the near future by the use of molecular PET imaging of tau and amyloid pathology that will allow the presence and location of neurodegenerative pathology to be defined (Scott et al., 2016).

Our results hold the promise of guiding improvements in protection from head injury, such as the development of novel helmet designs. Currently most TBI mitigation strategies are designed to reduce head translational acceleration. However, it is not clear that this is the optimal strategy for reducing the mechanical forces that lead to neurodegeneration following TBI (King et al., 2003). By using high fidelity computational models of brain injury, we have shown it is possible to map out the brain tissue response to head loading and this information could be used to focus the design of mitigation strategies on reducing the level of maximal strain and strain rate within the brain with particular attention to areas where pathology is observed.

[Horse]

FWIW

https://nyhetsrum.folksam.se/en/2020/06 ... w.linkedin

In total, 27 different helmets were included in this year’s test series. The price of helmets varies from 140 SEK to 3200 SEK and the results clearly show that the price is not always decisive for how well a helmet protects. Of the usual conventional helmets, Biltema’s bicycle helmet with MIPS had the best result. It was also one of the cheapest helmets tested.

Best of all, the airbag head protection Hövding 3.0 came out. It received by far the best test result both with regard to shock absorption and oblique impact performance. Compared to the worst helmet, there is more than seven times less risk of sustaining a concussion in case of a head impact if Hövding is used.

– In general, Folksam’s tests show that there is a large variation of the results between the helmets in the various tests and that there is thus potential to make them safer. All the seven conventional helmets that received our label “Recommended” have some form of protection for rotational loadings. But the fact that a helmet is fitted with rotational protection is no guarantee that it is a safe helmet. One of the helmets that comes out worst in the test has rotational protection, says Helena Stigson.

[Hot_Air]

Biltema’s bicycle helmet with MIPS had the best result. It was also one of the cheapest helmets tested.

In cycling helmets, MIPS has been used – and tested – extensively. MIPS-equipped helmets won all the tests I’ve read, and I wonder if we’ll see more motorcycle helmets with MIPS (or Wavecel) now that stricter ECE testing is imminent. Bell already makes eight different motorcycle helmets with MIPS: five lids for dirt biking, and three for road and track.

Best of all, the airbag head protection Hövding 3.0 came out. It received by far the best test result both with regard to shock absorption and oblique impact performance. Compared to the worst helmet, there is more than seven times less risk of sustaining a concussion in case of a head impact if Hövding is used.

Seeing the test results, won by the Hövding airbag helmet, suggests that airbag protection for the neck could be valuable. I wonder if Dainese has the right idea with its D-Air? It allows enough flexion to allow the neck to act as a shock absorber, yet cushions the neck from extreme movement.

[Hot_Air]

I posted about the UCL research on computer simulation of head injuries which IIRC suggested that neck movement acts as an impact absorber. The implication being that, if you prevent head movement, the energy is absorbed elsewhere - potentially by the brain moving within the skull. And that's not always a good thing.

Have you seen this publication?

Neck protective devices for motorcyclists have been introduced fairly recently but there is no standard method to evaluate their performance. The goal of this study is to compare the response of riders’ necks to direct impacts on the helmet with and without such a device. We investigate three common types of cervical injury mechanisms i.e. hyperflexion, hyperextension and lateral bending using finite-element method. The rotational movement of the head with respect to the torso, the neck shearing and axial loads and the stress distribution throughout the cervical vertebrae show that using the investigated type of neck protective device, which is designed to restrain the head–neck motion, can in some cases increase the risk of neck injury. Hence, the design of such devices needs further study and their assessment requires the introduction of relevant standards of evaluation.

And this?

To prevent motorcyclists' cervical spine injuries, many passive safety devices, commonly named neck braces, are available. This work aimed to promote a methodology to investigate how injury mechanisms or injury severity involved with cervical spine safety devices could be modified or avoided. Multidirectional head impact conditions were simulated on the head–neck–thorax isolated segment by testing three different neck brace technologies and a reference simulation without any protection. The tested devices did not show signfincant changes regarding the whole neck kinematics. The interactions with thorax or helmet component were an important issue for safety system capability to control joint kinematics. Rigid or semi hard neck braces' efficiency was observed with the shift of upper cervical spine injuries to the mean cervical spine injuries location. On the other hand, the lower cervical spine injury risk was not significantly modified. The soft device tested did not show any efficiency by comparison to the reference simulations.

Frustratingly, more details of these studies are behind a paywall

Siamak Farajzadeh Khosroshahi, Mazdak Ghajari & Ugo Galvanetto (2019) Assessment of the protective performance of neck braces for motorcycle riders: a finite-element study, International Journal of Crashworthiness, 24:5, 487-498, DOI: 10.1080/13588265.2018.1478937

J. Sun, A. Rojas, R. Kraenzler & P. J. Arnoux (2012) Investigation of motorcyclist safety systems contributions to prevent cervical spine injuries using HUMOS model, International Journal of Crashworthiness, 17:6, 571-581, DOI: 10.1080/13588265.2012.700097

[Horse]

Nope, and nope.

Where's the 'sweet spot', protect the neck without increasing brain injury? That's probably a fairly important factor

[Hot_Air]

Where's the 'sweet spot', protect the neck without increasing brain injury?

This question – now we’re emerging into the airbag era – is central to how we chose the right airbag, and how manufacturers evolve airbag design. Will we see more independent research published? I hope so!

What happens to the learning from MotoGP? Dainese, Alpinestars and In&Motion have all been using MotoGP for airbag development. But they came up with different answers to neck protection for road riding: nil (Astars), some (Dainese) and lots of neck protection (In&Motion).

Out of the three brands, only In&Motion appears to have the same airbag for MotoGP and consumers. I imagine the algorithms differ, but the MotoGP airbag looks like it gives the same coverage as the consumer version (judging by its airbag race crash video).

[Horse]

How many manufacturers make suits for road use that have a stylish, irrelevant - and potentially dangerous - 'hump'. Then, as you have pointed out, apparent lack of interest in making gear that meets higher protection levels.

So, you want to trust to build the 'best' protection for riders?

[Horse]

Where's the 'sweet spot', protect the neck without increasing brain injury?

Will we see more independent research published? I hope so!

The UCL stuff - and that's AFAIK only looking at biking as an 'add on' - is the only one I know of, and even that's because I happened to attend a presentation about their main work.

Their work involved US sports stars, who are both the subject of multi-angle, high definition, video recording, but also receive exceptional medical care, so scans and records are available. This video allows generation of computer models of impacts, determining forces involved that act on the brain, then comparison with actual injuries. They have also designed a more realistic [better than standard crash test dummy] instrumented neck. That would allow, I guess, testing of various restraints.

But this sort of stuff needs to be funded. Safety first, within budget?

[Horse]

Plnking these links here, for want of the enthusiasm of finding a more appropriate thread

https://spiral.imperial.ac.uk/bitstream ... reenOA.pdf

Influence of the Body on the Response of the Helmeted Head during Impact

The most frequent type of injury that causes death or disability in motorcycle accidents is head injury. The only item of protective equipment that protects a motorcyclist’s head in real-world accidents is the safety helmet. The protective capability of a helmet is assessed, according to international standards, through impact of a headform fitted with the helmet onto an anvil. The purpose of the present work was to study the influence of the presence of the body on the impact response of the helmeted head. Full-body and detached-head impacts were simulated using the Finite Element (FE) method. As a consequence of the presence of the body, the crushing distance of the helmet liner was drastically increased. This evidence indicated that the effect of the body should be included in impact absorption tests in order to provide conditions that are more realistic and stringent. The solution to an analytical model of the helmeted headform impact revealed that increasing the headform mass has the same influence on impact outputs, particularly the liner crushing distance, as including the whole body in impact tests. The added mass was calculated by using a helmeted Hybrid III dummy for an impact configuration frequently occurred in real-world accidents.


https://spiral.imperial.ac.uk/bitstream ... reenOA.pdf

Effects of the presence of the body in helmet oblique impacts

The oblique impact methods of motorcycle helmet standards prescribe using an isolated headform. However, in accidents the presence of the body may influence impact responses of the head and helmet. In this study, the effects of the presence of the body, in helmet oblique impacts, are investigated. Using the Finite Element method, oblique impacts of a commercially available helmet, coupled with a model of the human body, are simulated. A comparison between full-body impacts and those performed with an isolated headform show that the presence of the body modifies the peak head rotational acceleration by up to 40%. In addition, it has a significant effect on head linear acceleration and the crushing distance of the helmet’s liner. To include the effect of the body on head rotational acceleration in headform impacts, modifying inertial properties of the headform is proposed. The modified inertial properties are determined for a severe and frequent impact configuration. The results of helmet impacts obtained by using the modified headform are in very good agreement with those of full-body impacts; this verifies the accuracy of the proposed method.


https://spiral.imperial.ac.uk/bitstream ... 9953-1.pdf

The traumatic brain injury mitigation effects of a new viscoelastic add-on liner


https://spiral.imperial.ac.uk/bitstream ... lectic.pdf

Optimization of the chin bar of a composite-shell helmet to mitigate the upper neck force


Follow some of the references, or Google the authors, there's more from the same team.

[Hot_Air]

For anyone missing their fix of airbag videos on YouTube, ADAC has just tested a new flock of airbags. Those pesky Germans have been doing it again: testing-airbags-to-see-if-they-work

Where's the 'sweet spot', protect the neck without increasing brain injury? That's probably a fairly important factor

I bumped into a surgeon who’s operated on a tonne of motorcyclists – small world, eh? – and he wasn’t into the idea of letting the neck move to reduce brain trauma. But he was totally into having airbag protection for the neck. His one criticism of airbag-neck-protection was that it shouldn’t deflate (current airbags deflate post-crash, which is a letdown ).

[Horse]

This one (Held) seems to remain inflated.

[Horse]

I bumped into a surgeon who’s operated on a tonne of motorcyclists – small world, eh? – and he wasn’t into the idea of letting the neck move to reduce brain trauma.

I won't be talking to mine for a couple of months (all being well), even then will be concentrating on my health rather than other riders

[Bike Breaker]

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