topbanner_forum
  *

avatar image

Welcome, Guest. Please login or register.
Did you miss your activation email?

Login with username, password and session length
  • August 18, 2018, 06:54 AM
  • Proudly celebrating 13 years online.
  • Donate now to become a lifetime supporting member of the site and get a non-expiring license key for all of our programs.
  • donate

Last post Author Topic: bicycling suddenly a British speciality?!  (Read 12035 times)

IainB

  • Supporting Member
  • Joined in 2008
  • **
  • Posts: 7,139
  • Slartibartfarst
    • View Profile
    • Read more about this member.
    • Donate to Member
Re: bicycling suddenly a British speciality?!
« Reply #25 on: April 28, 2016, 11:11 AM »
@tomos: Looks like rather a nice bike - and pretty sturdy. Thanks for the link.

IainB

  • Supporting Member
  • Joined in 2008
  • **
  • Posts: 7,139
  • Slartibartfarst
    • View Profile
    • Read more about this member.
    • Donate to Member
Re: The Bike Shed - query re Bergamont Vitess 5.0
« Reply #26 on: July 21, 2017, 02:55 PM »
@tomos:
^ here's a link -- I got the 2015 model but, AFAICS, there were only cosmetic changes for the 2016 model.
Bergamont Vitess 5.0

The V6 model is lighter again, but they didnt have it in stock, and I was happy enough with this one weightwise (and pricewise). Beyond that I cant say much as I'm pretty ignorant of bikes and bike parts. It's at 300+km now and going nicely apart from the saddle which is bruising (!). The shop has offered to let me test saddles, just have to find the time.
__________________________
One of my cycling buddies is considering buying a second-hand Bergamont Vitess 5.0.
What is your view of the bike now? Did you also find a less "bruising" seat for it?
« Last Edit: July 24, 2017, 03:12 AM by IainB »

tomos

  • Charter Member
  • Joined in 2006
  • ***
  • Posts: 11,290
    • View Profile
    • Donate to Member
Re: bicycling suddenly a British speciality?!
« Reply #27 on: July 22, 2017, 02:33 AM »
One of my cycling buddies is considering buying a second-hand Bergamont Vitess 5.0.
What is your view of the bike now? Did you also find a less "bruising" seat for it?

I loved the bike -- was fast, light, solid -- used it mainly going into town - 14 km one way, but also a bit in the woods.

Now I did have problems with the bike -- but they were more to do with me not fitting the bike design, than with the actual bike. Some background:
From years of drawing on computers, my wrists are very, eh, 'sensitive', for want of a better word. I cannot put a lot of weight on them; have to be careful not to work with the hand/wrist in a bent position. I also have minor shoulder problem on one side, which possibly related to hips being slightly out of line.

The bergamot has lower handlebars than my previous bikes, and they are designed to lean on with the wrists bent. With that combination I ended up with wrist problems and neck problems and stopped using it. I was away for three weeks last year, and a friend of mine borrowed the bike -- she loves it and ended up buying it from me -- I got a new camera with the money...

So the bike is still in use and going well after a year -- very hard to say exactly, but has been doing maybe an average of 70km a week over the temperate months (about ten months use since it was bought).

I dont know how much value that info has, also considering I've only ever been a casual cyclist, so would possibly be judging differently to anyone who calls themselves a cyclist.
Tom

IainB

  • Supporting Member
  • Joined in 2008
  • **
  • Posts: 7,139
  • Slartibartfarst
    • View Profile
    • Read more about this member.
    • Donate to Member
Re: The Bike Shed - bicycle ergonomics
« Reply #28 on: July 23, 2017, 07:53 AM »
Thanks.
I know what you mean about the wrists bent position. It hurts because it puts unnatural strain on joints and ligaments - which are not really built for that load.
« Last Edit: July 24, 2017, 03:13 AM by IainB »

Shades

  • Member
  • Joined in 2006
  • **
  • Posts: 2,355
    • View Profile
    • Donate to Member
Re: bicycling suddenly a British speciality?!
« Reply #29 on: July 23, 2017, 12:09 PM »
City bikes are much more useful for casual cycling and have the advantage that you can do much more with it. Now a mountain bike is an excellent bike for the purpose it is designed for. But you are not inclined to take your bike out to get a few days worth of groceries on it, because it ain't that practical.

And for most people that is enough to not consider doing any bicycling., while a more practical model could. I grew up in the Netherlands, which has dedicated infrastructure for cycling and you can easily move 30 to 50 kilo of gear/groceries/children/whatever with a properly loaded standard bicycle. Sure, travel time is longer, but you hardly need any time for parking and often you can leave your bike much closer to the entrance of the place where you need to be.

To me, it is weird that so many people are afflicted by mountain bikes. Even here in the capital of Paraguay there are many cycle stores, but you cannot buy any other type of bicycle than mountain bikes. Friends I know here, are shipping a sea-container here from NL and I asked if there was space for a city model bicycle. Unfortunately, that is the most practical way to get a non-mountain bike here.

The activity of cycling is healthy, but I have my doubts about the posture the cyclist must assume on a mountain bike. Sitting straight up on a city bike model is less efficient aerodynamically. But if you cross your arms in front of your torso and bring your torso down towards the curved handlebar, so that your hands have good grip on the straight part of the curved handlebar, the aerodynamic efficiency is almost equal to that of a mountain bike, there is no strain on any injured elbow or wrist and you still have the advantages of the city bike model.

Speaking from personal experience, I always found that way of cycling very comfortable and makes you more stable as you lower your point of gravity during cycling, which comes in handy when wind batters you from either your right or left side (instead of head on).

*edit: better description of body positioning on city bike model
« Last Edit: July 23, 2017, 12:23 PM by Shades »

IainB

  • Supporting Member
  • Joined in 2008
  • **
  • Posts: 7,139
  • Slartibartfarst
    • View Profile
    • Read more about this member.
    • Donate to Member
Re: The Bike Shed - drag effect in cycling.
« Reply #30 on: July 23, 2017, 09:28 PM »
If cycling on roads, which can make for quite fast progress, there are two drag effects worth considering:
  • (a) Air drag (friction): on the forward-facing surfaces of of the cyclist's body. Many cyclists do not appreciate how much energy they have to expend pedalling to overcome air drag. The drag effect is more noticeable the faster one goes. That drag can be significantly reduced by fitting (say) the drop-handlebars of a road bike. The trouble with drop bars is that the handbrake levers are lower also. I tend to find that long periods in the crouched position for drop bars are tiring and restrictive and can hurt my wrists a bit. Thus, at lower speeds, I like to ride my road bike sitting up more straight and with my hands gripping the top (straight) part of the handlebar - which is risky as the brakes are too far away to get hold of in a hurry. So I have an ancillary pair of handbrakes fitted on the top part of the handlebar, angled down and just right ergonomically, positioned right within reach of my extended fingers when my hands are on the upper part of the handlebar - very comfortable.

  • (b) Rolling resistance (friction): on the tyres as they touch the road. Many cyclists do not appreciate how much energy they have to expend pedalling to overcome rolling resistance. This drag can be considerably reduced/minimised by fitting the smoother road tyres (i.e., not the knobbly multi-terrain type tyres) - which is what I usually do for my daughter's bike. Keeping them at max pressure also helps to minimise rolling resistance.


Reduced drag can equate variously to:
  • greater efficiency (less energy used),
  • better energy reserves, improving the potential ability to cover greater distances,
  • higher average speeds,
  • a more enjoyable ride,
  • a less tiring ride,
  • improved motivation to cycle because one's ability to cover greater distances in a more relaxed fashion is enhanced.

The last point (motivation) in the list could be significant - e.g., when taking on the challenge of longish bike-rides, the challenge is reduced. Motivation and enjoyability could also provide mutually reinforcing feedback.
« Last Edit: July 24, 2017, 03:11 AM by IainB »

IainB

  • Supporting Member
  • Joined in 2008
  • **
  • Posts: 7,139
  • Slartibartfarst
    • View Profile
    • Read more about this member.
    • Donate to Member
Re: The Bike Shed - efficiency, ergonomics and knee-joint health.
« Reply #31 on: July 24, 2017, 03:10 AM »
@Shades:
I think I understand most of the points you make above, but am confuzzled where you say:
But if you cross your arms in front of your torso and bring your torso down towards the curved handlebar, so that your hands have good grip on the straight part of the curved handlebar, the aerodynamic efficiency is almost equal to that of a mountain bike, there is no strain on any injured elbow or wrist and you still have the advantages of the city bike model.
- "cross your arms in front of your torso"? How does that work?    :tellme:

Also, "afflicted by mountain bikes"?  Did you intend to mean "think they need to use" or were you being sarcastic? Sounds like mountain bikes are the only option (no choice) in Paraguay.
The gearing (gear ratios) of bikes is generally optimised for the kind of terrain the bike is intended for use on. The gearing of mountain bikes is thus all wrong for road use anyway - less efficient and more energy-draining. I always shake my head in wonderment when I see people on mountain or off-road bikes pedalling furiously along a road/pavement but actually moving rather slowly and not realising the implications. Ergonomics is all-important. A badly-designed bike - or one with the wrong gear ratios or that is the wrong size for the individual using it - can be very inefficient in use, and may even cause injury - e.g., kneecap damage, leading to patellofemoral arthritis

A well-designed bike efficiently converts and optimises the energy of muscle power into forward motion. Trick bikes, for example, might be great for bike tricks, but have shallow depth frames where the length of the fully-extended leg is not usually accommodated, so a lot of potential energy is lost unless one stands up from the saddle - which is inefficient anyway. So they are not of much use for road-cycling, but I have seen them used for that.

Interestingly, riding a correctly-sized bike in a low gear a lot is recognised as a very good way to repair knee damage in patellofemoral arthritis. I know this to be the case from personal experience - because it was the recommended remedy/treatment to repair the patellofemoral damage I had unwittingly incurred between the ages of 16 to 20 from too much ski-ing, weight training with heavy squats, distance road-running, and intensive soccer-playing. The arthritis surfaced painfully in my 30's whilst I was walking/climbing over some NZ mountain ranges and since then has been one good reason I try to keep regularly cycling. The arthritis thus rarely bothers me as the rough bits (criss-crossed grain of repaired cartilage) on the joints at the back of the patellas are kept smooth/polished and healed by virtue of the gentle repetitive cycling motion (in low gear), which also stimulates blood flow to the joints to help repair/maintain the damaged areas.
« Last Edit: July 24, 2017, 09:41 AM by IainB, Reason: Minor corrections. »

wraith808

  • Supporting Member
  • Joined in 2006
  • **
  • default avatar
  • Posts: 9,635
    • View Profile
    • Donate to Member
Re: bicycling suddenly a British speciality?!
« Reply #32 on: July 24, 2017, 09:31 AM »
I think I understand most of the points you make above, but am confuzzled where you say:
Quote from: Shades on July 23, 2017, 02:09:57 PM
But if you cross your arms in front of your torso and bring your torso down towards the curved handlebar, so that your hands have good grip on the straight part of the curved handlebar, the aerodynamic efficiency is almost equal to that of a mountain bike, there is no strain on any injured elbow or wrist and you still have the advantages of the city bike model.
- "cross your arms in front of your torso"? How does that work?   

cycling.jpg

Hard to put into words in a post, even for a native English speaker.

cycling.jpg

IainB

  • Supporting Member
  • Joined in 2008
  • **
  • Posts: 7,139
  • Slartibartfarst
    • View Profile
    • Read more about this member.
    • Donate to Member
Apropos of this:
Then today I read about this lady Belgian cycling cheat. It was disturbing enough for me to read a couple of years ago of the revelations about Lance Armstrong's enhancement drug-taking - which retrospectively cancelled all his prior TdeF wins (and quite rightly so) - but I had not realised that one could now cheat with "mechanical doping" - fitting concealed electric motors on the bike. Amazing what some people will do to "win".

Just saw this video today. Pretty impressive and well-concealed technology.
Exclusive: we tested the rigged race bike (Is in French, but self-explanatory.)

Shades

  • Member
  • Joined in 2006
  • **
  • Posts: 2,355
    • View Profile
    • Donate to Member
Re: bicycling suddenly a British speciality?!
« Reply #34 on: January 10, 2018, 09:31 AM »
That video is old news. Several cyclists have cut their sporting career short when they applied this concept to their bike(s). And rightfully so. Still, the idea and execution is excellent, but not for sports. The consumer market would benefit greatly from this concept. And likely much more money to be made. As I am Dutch and grew up using bicycles a lot, I would even consider using such a bike here in Paraguay. Traffic can be very problematic here and a commute that lasts 20 minutes without traffic can easily take a1 to 1.5 hour with traffic.

With such a bike traffic wouldn't be any problem anymore, I would get (more) exercise than I do now and I won't be sweaty all over after using the bike. With the amount of sun hours here in this country, I think iit is possible to charge it using solar energy alone, during work hours. The model of bike that is used in the video above, I wouldn't use. A city bike would make much more sense, as you can easily pick up your daily groceries too. Without wasting time finding a spot for your vehicle and hoping no-one else dents your car. I see only advantages with this concept. Bicycles that have a way to assist their user have a few things in common. They are all very ugly to look at and it is easy to steal the parts providing the assistance. Hence you pay a lot for insurance of such a bike. All of that is gone with this concept.

tomos

  • Charter Member
  • Joined in 2006
  • ***
  • Posts: 11,290
    • View Profile
    • Donate to Member
Re: bicycling suddenly a British speciality?!
« Reply #35 on: January 10, 2018, 10:01 AM »
I would even consider using such a bike here in Paraguay. Traffic can be very problematic here and a commute that lasts 20 minutes without traffic can easily take a1 to 1.5 hour with traffic.

With such a bike traffic wouldn't be any problem anymore, I would get (more) exercise than I do now

I commuted (by bike) for ~10 years largely in and around Dublin city centre. Traffic was particularly bad at the time -- and exhaust fumes too, so I got the best mask/filters I could get at the time. Filters though cannot filter diesel exhaust fumes (dont know if true but I've heard that the molecules are too small). I grew to hate diesel exhaust fumes with a passion, and still do to this day.
Tom

IainB

  • Supporting Member
  • Joined in 2008
  • **
  • Posts: 7,139
  • Slartibartfarst
    • View Profile
    • Read more about this member.
    • Donate to Member
I originally saw the "Angles mortes" video in an earlier version, some years ago. "Angles mortes", which translates (literally) to "Deadly angles", is referred to by the term "Blind spots" in English.
I thought I had already posted about this video on the DC Forum, but, on searching, I could not seem to find it.
So, here it is. It is an excellent video, taken over a year, with bike cameras mounted fore and aft. It demonstrates quite clearly the dangers of cycling in Paris, where road/driving laws and rules to protect cyclists are apparently ineffective as they seem to be routinely ignored by motorised road vehicle users. Maybe they are infeasible/unenforceable laws/rules - I don't know.

"Blind spots"


In Auckland (NZ) where I live, they are extending "bike lanes" throughout the city and alongside (but separate to) some stretches of motorway. They are implementing it with what seems to be a pretty costly set of changes to the existing roading system, which, as a ratepayer, I can't see being cost-justified. However, if it helps to reduce bike accidents/deaths, then I would think it will have been worth it.
One of the stated intentions is apparently to try to encourage the use of bicycles and correspondingly reduce car use, but only time will tell whether that eventuates.

What reminded me to post a comment about this in the first place was that I was reading today an interesting article about "a type of road junction that causes cyclists to be killed". Specifically, it is Ipley Cross - a crossroads junction in Hampshire, UK.
The post is: Collision Course: Why This Type Of Road Junction Will Keep Killing Cyclists, and I have copied it in the spoiler below (it's quite a long article).
(Copied below sans embedded hyperlinks/images.)
Spoiler
Collision Course: Why This Type Of Road Junction Will Keep Killing Cyclists
by Bez
January 7, 2018

Ipley Cross is a largely unremarkable place, an open plain where two roads cross: Beaulieu Road running north-to-south and Dibden Bottom running roughly east-to-west.

Yet it is a place of notoriety. For good reason.

Two Deaths And A Lucky Escape
In August 2011 a 15 year old boy was cycling along Beaulieu Road when he was struck from his left by a driver who failed to see him and failed to give way at the junction. The boy was sent flying, but somehow escaped with only a broken collarbone.

In May 2012 a second, almost identical incident occurred. Mark Brummell was cycling along Beaulieu Road when he was struck from his left by Stephen Chard, who failed to see Brummell and failed to give way at the junction. Brummell was killed.

In December 2016 a third, almost identical incident occurred. Kieran Dix was cycling along Beaulieu Road when he was struck from his left by Viral Parekh, who failed to see Dix and failed to give way at the junction. Dix, too, was fatally injured.

Chard was charged with causing death by careless driving and pleaded guilty; Parekh was charged with causing death by dangerous driving and pleaded guilty to causing death by careless driving, but was found not guilty of the more serious offence by a jury despite having driven through the junction’s “give way” line at 37mph without slowing.

Two questions present themselves.

Firstly, why it that the same collision keeps occurring at this junction? And secondly, why is such a standard of driving considered only to be “careless” rather than “dangerous”?

As we shall see, the answers to both are closely related.

By understanding one of the most likely causes for “failure to see” collisions at this junction, not only can we answer those questions but we can offer surprisingly straightforward solutions.

The Existing Layout
Ipley crossroads has a very simple layout: two straight sections of road cross at an angle of 69 degrees, with the north-south road (Beaulieu Road) having priority.


The innocuous, yet dangerous Ipley crossroads
Sight lines are good, although the rightward view from the easterly approach is affected somewhat by a gentle slope which rises to the northeast of the junction.

So, if it’s so easy to see, why is it apparently so easy to fail to see?

Hidden In Plain View
Far and away the most plausible answer is a phenomenon known as “constant bearing, decreasing range”, or CBDR. Originally noted by sailors, it is the phenomenon whereby two vessels, or vehicles, moving at steady speeds in straight lines towards a collision will maintain the same bearing.

If you’re a dab hand with basic trigonometry, you can probably figure the principles out for yourself, but if not then of course Wikipedia has an explanation.

CBDR is required knowledge in maritime and aviation, where ships and aircraft travel significant distances with constant speed and bearing, but it is rarely taught in the context of highways, where motion is generally less constant. But it is nonetheless important where two straight routes cross: not just two roads, but also where roads and railways cross at unsignalled level crossings (a design which is rarely if ever found in the UK but which is not uncommon in parts of the US).

Sailors and pilots are taught to detect ships and planes at a constant bearing and to take avoiding action. When it comes to drivers, however, things are very different, because almost all motor vehicles have a design flaw which means not only that a CBDR condition precedes a collision, but that unless (as we shall see) the driver does one of two things, the same condition means that the driver will never even see the phenomenon occurring.

That design flaw is the front ‘A’ pillar, at the edge of the windscreen.

The Pillar Shadow
Take a look at this plan view of a Vauxhall Zafira (as driven by Viral Parekh). When the driver looks towards the horizon, the front pillar will obscure some of the view. The red ellipse represents an approximate cross section at that point, with the shaded area beyond it being obscured as a result.


The driver’s blind spot in a Vauxhall Zafira.
Once you extrapolate that obscured area, the extent of its effect is obvious. Here’s the same set of lines drawn on the Zafira, scaled up and overlaid on Ipley Cross.


A projection of the driver’s blind spot.
At the position shown, approximately 100m from the junction at Ipley Cross, the pillar obscures roughly 12m of Beaulieu road. That’s six bicycle lengths: enough to hide not just a cyclist but a small group of riders.

Of course, as the driver approaches that junction, that obscured section of road moves towards the junction with them. As does the cyclist.

Parekh’s car had a black box type device, which (contrary to his statements to police) recorded his approach to the junction at a steady speed of 37mph. At this speed it would have taken six seconds to cover the 100m to the collision, and the following image shows the approximate areas obscured by the Zafira’s pillar at six points in time representing each incremental second leading up to impact, with the red area showing the pillar shadow one second prior to impact.


The obscured section of road becomes smaller as the driver nears the intersection.
Although the obscured section of road becomes smaller as the driver approaches, it remains large enough to completely obscure a bicycle until less than a second prior to impact: too late for either party to react.

The light blue line in the following diagram represents the approximate length of a bicycle and fits comfortably within the pillar shadow at one second before impact.


The light blue line represents the cyclist.
Naturally, as per the conditions of a collision course being signalled by a constant bearing, for any speed of the approaching car there is a speed at which a cyclist will remain obscured by the front pillar almost until the point of impact. The angles of the triangles define a ratio of speeds, and with this geometry that ratio is a little over 3:1.

So, in the case of a vehicle moving at 37mph westwards along Dibden Bottom, the CBDR speed southbound along Beaulieu Road is roughly 13.5mph. A very plausible speed for a cyclist.

But such a degree of coincidence is actually not required.

Due to the width of the pillar and the extent shadow it casts, which is much larger than a bicycle until impact is inevitable, true CBDR is not even necessary: it would be perfectly possible for a cyclist to be moving at around 17.5mph and then hit the brakes two seconds prior to impact, without ever appearing in the driver’s view.

There’s a whole range of steady speeds at which someone could approach this junction from the north and remain obscured to a driver approaching at a steady speed from the east (and, likewise, also from the south and east respectively).

Crucially, for any likely speed of an approaching car, any speed in that range is a perfectly feasible speed for a cyclist.

But there’s one more thing about Ipley Cross that makes it especially dangerous.

Critical Angles
Keen triangle enthusiasts may have started thinking about this already, but there are of course three angles to consider here.

The first is the angle between the two approach paths, which is a constant value defined by the road. At Ipley Cross this is 69 degrees.

The second is the angle between the driver’s line of travel and the line from their eyes to the front pillar. This will vary depending on the vehicle and the driver, but the approximations above put the angle at around 17 degrees to the centre of the pillar.

The third is the angle between the cyclist’s line of travel and the line from their eyes to the vehicle which will hit them.

At this location, with this vehicle, it is 94 degrees.

A car which is on a collision course at Ipley Cross with a cyclist who is obscured from the driver’s view by the front pillar will approach the cyclist from behind.

Ipley Cross is constructed in such a way that not only is it possible for a careless driver to drive straight into a cyclist without seeing them until a fraction of a second before impact, but under the exact same circumstances it is also possible for that cyclist not to see the car that hits them until the same moment.

If anyone were to take a highway engineer to a wide open space and ask them to design a junction which would readily enable two road users to collide with neither of them ever seeing each other, I doubt any would be able to manage it.

Yet this is precisely what exists.

The exact numbers, of course, depend on the driver’s height and seating position, the geometry of their vehicle, and—if you wanted to apply this to other locations—the angle at which the roads meet. The 3:1 speed ratio will vary slightly according to all these factors, and it will not always be the case that the deadly vehicle will be so hard for its victim to see, but the angle between a driver’s line of travel and the line between their eyes and the pillar will always be such that it is the slower road user who is at risk of not being seen.

The point is this: given the design of almost every motor vehicle on the road, the crossing of two straight roads can make for a perfect storm when combined with typical speeds of drivers and cyclists. Ipley Cross represents possibly the most perfect of such storms.

These collisions are, therefore, inevitable—aren’t they?

Of course not.

Human Error: The Eternal Excuse
“None of us are perfect drivers,” remarked Parekh’s defence barrister, attributing the whole affair to “human error”.

The human error in this case, and the other cases, may have been for the drivers to have maintained a constant speed (as we know Parekh did) without having physically moved their head either side of the pillar to rigorously scan the area ahead and to their right.

There are two very simple solutions to the very real risk of a driver-vs-cyclist CBDR collision.

Firstly, by slowing down significantly, any vehicle approaching from the right at a constant speed will move out of the obscured area and into view at the right of the windscreen.

And secondly, significant movement of the head will bring previously obscured sections of road into view.

It’s quite plausible that these simple strategies—either of them—could have prevented two fatalities at this one junction.

One of those strategies can, however, be easily enforced.

A Simple Solution
In 2015, nearly three years after the death of Mark Brummell, a local resident sent a pencil sketch to councillor David Harrison, which he passed on to Hampshire County Council.

It was a simple plan of Ipley Cross, with one modification: the western approach now had a short kink at its meeting with Beaulieu Road, making the junction offset.


Before, and a potential after.
With this design, no longer would it be reasonably possible for any driver to simply blow through the junction. Drivers would have to come almost to a stop.

This design would, very simply, force the slowing down that eliminates the problem of CBDR.

The image above is, of course, a mock-up. The junction was never altered.

Two years after that simple sketch was handed to the authority responsible for the junction, Kieran Dix was dead.

Is This Not Dangerous?
And, lest we forget: what of the criminal proceedings against Parekh? Why is it not deemed “dangerous” to approach this junction at 37mph without slowing?

We must note that there are two parts to the definition of dangerous driving. Firstly the standard of driving must be “far below what would be expected of a competent and careful driver”, and secondly it must be “obvious to a competent and careful driver that driving in that way would be dangerous”.

People are often drawn to the term “far below”, which offers only a vague difference from “below” as used in the definition of careless driving, but generally the problematic clause is more likely the latter: it simply doesn’t matter how dangerous the driving is if it’s not obvious that it’s dangerous.

If we don’t teach people that to approach a junction at a constant speed is inherently dangerous, and if we don’t offer a basic explanation as to why, then it is surely not obvious to most people.

“Human error” may be real, but so are techniques to mitigate or eliminate its effects—and driver training is poor when it comes to equipping people with those techniques, let alone habituating them. (And let alone reviewing knowledge of those techniques every few years.)

It would appear from media reports that Parekh’s defence was simply that he did not see Dix; the implied logic being that since he saw no other vehicles he felt no compulsion to slow down. The jury’s acquittal equally implies that they agree with this logic: it was not obvious to them that failing to see another vehicle is anything other than unavoidable.

Yet, once the nature of a collision course is explained, the need to slow down becomes obvious.

The truly contemptible human error is not in a single person carelessly failing to see. It is in our failure to continually improve the training and licensing system so as to render the need to slow down obvious; it is in our incessant support of a system which cries “human error” as an excuse to do nothing, rather than as a stimulus to understand that error in order to create a solution.

Constant Bearing, Reducing Distance
So we can easily answer both of our original questions: why the same collision keeps occurring at this junction, and why driving straight through it at a steady 37mph is not deemed “dangerous” by law.

The question we still can’t answer is that of why, when clear solutions to both problems exist, no-one ever does anything about it.

We remain on the same bearing, heading for the next collision.

Copied from: » Collision Course: Why This Type Of Road Junction Will Keep Killing Cyclists - <http://singletrackworld.com/2018/01/collision-course-why-this-type-of-road-junction-will-keep-killing-cyclists/>
==============================================

What I find interesting about this is:
  • (a) that the explanation offered as being "Far and away the most plausible answer..." - i.e.. as to why that is a "killer junction" - is not proven, but is an argument hypothetically based on two concepts:
    • The conventional nautical navigation concept of CBDR ("Constant Bearing, Decreasing Range”);
    • The concept of the "Pillar Shadow" blind spot - being the potential forward-view blind spot radiating out from the driver's side (i.e., the RHS in this case) windscreen/door-pillar.
  • (b) that the only solution put forward would seem to be relatively unsatisfactory - i.e., it would seem to be potentially relatively expensive and a constipated re-arrangement of the junction, turning it into a technically inefficient (operationally costly) sort of permanent dog's-leg diversion. I'd call that "a workaround."
  • (c) that there is some past research in psychological perception that could be relevant in explaining why these accidents will continue to happen at this and other junctions.
  • (d) that there are already well-understood, tried-and-tested solutions that have been devised in the UK, to this and similar road-safety problems.

So, lets look at (c) and (d):
(c) that there is some past research in psychological perception that could be relevant in explaining why these accidents will continue to happen at this and other junctions.
  • Some years back, I read about an intriguing piece of psychological research that had car insurers interested. The research had identified the probable cause of why accidents at T-junctions happen, where the drivers involved would write on their insurance claim forms "I just didn't see the other car/motorbike.", or "The other driver must have been driving like a bat out of hell, because he wasn't there when I looked!" - OWTTE.

  • The researchers had established by experiment that the human brain seems to have an instinctively automatic, accurate and fast response to any movement within the field of view. Sensory electrodes applied to subjects' heads showed this to be the case, and furthermore showed that any movement in an otherwise stationary field of view would immediately fire up the brain in a basic survival mode response. We are, it seems, very good at detecting movement, without even thinking about it. Then the researchers wondered why this was, and why the survival responses occurred. They postulated that this was probably a primitive developed survival instinct, when, as hunter-gatherers, we would need to be constantly scanning for sign of threats - movement from potential/concealed predators in the environment (plains or forest) we were walking through. Those who spotted the movement were more likely to have survived than those who did not.

  • So the researchers wondered why this unerringly accurate survival instinct did not fire up at those strange T-junction accidents where the threat was simply apparently not perceived. After some experimentation, they figured out that, at a T-junction where the top bar of the T is the main road, the driver of a car is glancing to his right and/or left, looking through the right/left side windows. At each glance, the brain takes the frame of the window as a frame of reference for the field of view through that window, and any movement in that frame relative to the frame itself is immediately sensed/observed.

  • Further experimentation showed that the brain does not perceive a moving object where that object appeared to be stationary within the frame - which is pretty much exactly the condition of CBDR ("Constant Bearing, Decreasing Range”). Only that which moves within the frame is perceived by the brain (as a threat), and non-threats (the rest) are ignored. Thus explaining the "I just didn't see the other car/motorbike." statements - they are likely to be absolutely true statements.

  • Thus it would probably be incorrect to say that this illustrates "driver error" or "human error", since everything in the brain is perceptually doing exactly what it should. What it probably does illustrate though is that we were not designed to drive cars, as we have inbuilt "driving blind spots" in our sensory perception that were necessitated for our survival in the natural environment. Which is why we now know that we should take extra care as we approach a junction, as we may be literally blind, unable to perceive some of the action around us in the artificial environment.

(d) that there are already well-understood, tried-and-tested solutions that have been devised in the UK, to this and similar road-safety problems.
  • Some of the most interesting, forward-thinking and sometimes non-intuitive solutions were realised and deployed in the roading infrastructure redevelopment in the building of the Milton Keynes new city (UK). The MK boundary set by the planners encompassed several villages, towns (the largest being Bletchley) and large spaces of open agricultural land, portions of which were targeted for development as new "villages" and light industry zones - which latter were separated from the habitation areas. Several existing major arterial roads and railway routes passed through the designated MK city area.

  • Most of the roads had artificial landscaped embankments as protection where they passed nearby habitation areas. This contained the noise, disturbance and combustion engine fumes. The main arterial "A" roads were left unimpeded, with traffic lights where necessary at congested points or near Bletchley and other existing (older) established habitation communities. Many of the minor "B" roads were implemented as a network and a means to communicate efficiently between different communities and industrial zones within the MK area. These roads rarely had a traffic lights or ordinary stop/give way lines, since the planners had elected to put a roundabout at most junctions and let the traffic flows sort themselves out. The roundabouts worked so well that eventually many of the traffic lights and ordinary junctions had their traffic lights and lines removed and little dummy roundabout put there instead. This was done experimentally at first, and then done as a matter of course because the experiment was so incredibly successful. Other cities in the UK quickly learned from this, and they too began to replace traffic lights and ordinary junctions with these mini-roundabouts. Not only did the roundabouts improve the traffic flows, but also the accident rates at those junctions tended to decline significantly, even as traffic flows (the number of vehicles during different periods of the day) increased. In large part, this could have been attributed to the elimination of the opportunity for the CBDR frame perception blind spot to manifest itself (which was not known about at that time), because all drivers had to slow to the roundabout and only needed to look right to see and give way if a vehicle was approaching from that direction.

IainB

  • Supporting Member
  • Joined in 2008
  • **
  • Posts: 7,139
  • Slartibartfarst
    • View Profile
    • Read more about this member.
    • Donate to Member
Re: bicycling suddenly a British speciality?!
« Reply #37 on: January 10, 2018, 02:08 PM »
@Shades:
"That video is old news." That's correct. I wasn't suggesting that it was recent news. I was referring to the old comment -IainB (2016-04-26, 17:35:34)
The video says it was "Published on 24 May 2016".
I was merely being appreciative of the technology: "Pretty impressive and well-concealed technology." It looks very civilised and not like a kludgy aftermarket add-on.
That quote I linked to also included this:
...Kiwi cyclist who has an electric motor assist on his bike, and he said his Auckland commute could take up to 1½ hrs each way, by car, but only 30mins by this bike - and he arrived fresh and not in need of a shower as he would have usually done if he had cycled on pedal power alone. ...
What he sees as benefits are in my view a real plus, but traffic commutes put me off.
The things I don't like about traffic are traffic exhaust pollutants and noise. They can't be good for one. Especially the diesel fume particles and carbon monoxide, so I tend to avoid long commutes in traffic for that reason.
Hearing protectors of various types are easily available. I have recently been looking at facemask filters to help there, but have not come across any that I would see as necessarily being of much comprehensive use.

"Still, the idea and execution is excellent.". Absolutely, and I would like it for myself please (but not at any cost) and for most/all of the reasons/benefits that you suggest for yourself, though I would use it for my Trek SL1000 road bike - if I could - as that bike really does suit my peculiar needs and I want to keep it and not have to get another bike.

tomos

  • Charter Member
  • Joined in 2006
  • ***
  • Posts: 11,290
    • View Profile
    • Donate to Member
Re: bicycling suddenly a British speciality?!
« Reply #38 on: January 10, 2018, 02:40 PM »
"Blind spots"
https://www.youtube..../watch?v=gAethD1Io_Y

A lot shown in that Paris video seemed to be more along the lines of 'who cares about cyclists'.

NY not as bad as Paris, but they have bike fun there too --
Casey Neistat's Bike Lanes video:

Tom

IainB

  • Supporting Member
  • Joined in 2008
  • **
  • Posts: 7,139
  • Slartibartfarst
    • View Profile
    • Read more about this member.
    • Donate to Member
Re: bicycling suddenly a British speciality?!
« Reply #39 on: January 12, 2018, 08:48 PM »
^^ That's soo cynical, fining the cyclists. It's presumably all about the ticketing revenue targets that are set for the police officers to "achieve".
However, in the chaotic Paris and NY traffic scenes, it really would seem that bike lanes are arguably a joke, and one might well be better off not cycling.
Road traffic and bikes simply do not mix well, and (from a risk perspective) the cyclists will always come off worst - being physically vulnerable, and not paying any road tax for any special services.

IainB

  • Supporting Member
  • Joined in 2008
  • **
  • Posts: 7,139
  • Slartibartfarst
    • View Profile
    • Read more about this member.
    • Donate to Member
I commented above:
...Just saw this video today. Pretty impressive and well-concealed technology. ...
- but the cost was likely to be around 2 or 3 thousand USD, I think, So, not really sensible.

However, look what @Arizona Hot has just posted in the Interesting "stuff" thread:


This removable wheel will electrify your bike in 30 seconds

That looks like a brilliant solution. US$799 though ... that's approx 1.5 times the cost of my Trek SL1000 bike. Pity. Still, the price for this technology will take some time to normalise to the point where it becomes a commodity. I can wait.

Curt

  • Supporting Member
  • Joined in 2006
  • **
  • Posts: 7,342
    • View Profile
    • Donate to Member
Re: bicycling suddenly a British speciality?!
« Reply #41 on: January 13, 2018, 06:22 AM »
22 new USA eBikes you can actually get in 2018


« Last Edit: January 13, 2018, 06:30 AM by Curt »