Metropolitan Police stopping distance video in Charlie Alliston trial raises questions

Rich_cb wrote:

The video is not a good or fair comparison. I don't really think it matters in this case though. He had time to shout twice, therefore he had time to brake. It is obvious that he would have been able to reduce his speed far more quickly with a front brake in situ. Reduced speed would have made the collision less likely and even if it still occurred it would have involved less energy reducing the likelihood of serious injury.

he DID brake, from approx 18mph to approx 10mph (A speed given by the prosecution as within the range of speed upon impact), a speed that you would know is a dawdle and as per pretty much everyone else would be fine to go around someone fart arsing about in the road.

Do you brake to a complete stop as fast as you can possibly manage (Which is what the prosecution are saying you should do to avoid such) at the mere sight of someone potentially going to cross the road or is in the process of crossing the road, either in car or on bike when a fair few metres away?  99.99999% of all situations for all types of road user that would be an absolute no.

he had two lots of thinking to do, the first when he first acknowledged the hazard and braked, that takes up 1.5seconds thinking time for the unexpected situation plus a bit for mechanical action time.

When the deceased failed to get her shit together and cross in a normal fashion as would be expected he would have had yet another set of decisions to make (another 1.5s thinking time for the unexpected step back into him). At this point that is the 3.8sec from her stepping out and thus he had no time to brake further because at 10mph (A slow speed remember, she moves back into him).

Therefore unless you ask every single road user to come to a complete stop every time someone makes a move toward a crossing or a motor, cycle, equine, invalid carriage  etc comes to a junction, rounabout you have priority just in case they do the unexpected, then you cannot find the convicted rider of a slow moving bicycle guilty of wanton and furious riding because the law/justice system will not instist on the exact same set of values/responsibilities/actions for all those groups in any given scenario.

We know this already because those rules have being breached time and time and time again with the death of pedestrians and people on bikes by motorists with naught but a slap on the wrist if even any case to answer.

burtthebike wrote:

RedfishUK wrote:

I'm sorry but the ONLY valid test here would have been:-

The same bike with and without a front brake, any other test is meaningless

Almost right.  To be at least remotely valid, the same bike would have to be used, with a rider experienced in riding  both fixie and other bikes, but crucially, the test would have to be done multiple times, with the stop signal to the rider being random, so they wouldn't know whether they were stopping or not.  If they knew they were going to stop, the test is not realistic enough to be valid and it should have been challenged by the defence.

This, and same rider weight, in fact because the tester would have known the signal was coming they'd still have a significant advantage, also that of not having multiple scenario unfold plus fear/panic/emotions possibility of being hurt/hurting someone which all takes up valuable time.

Human beings are not fucking robots as plod/prosecution are trying to insist you have to be to be not found guilty. 

I look forward to the same set of values being applied on UK roads from now on for all user types with the resulting tens of thousands of motorists being charged with dangerous driving annually for relatively minor incidents that may or may not result in death or injury. the brakes in themselves were in any case not relevant given the timescales involved, the expectation is that he could think faster than any human having had to make multiple decisions/thought processes as I described above. ones that motorists are not expected to do every single day and due to that are absolved with regularity despite other factors in any case even aggravating ones such as excess alcohol.

BehindTheBikesheds wrote:

he DID brake, from approx 18mph to approx 10mph (A speed given by the prosecution as within the range of speed upon impact), a speed that you would know is a dawdle and as per pretty much everyone else would be fine to go around someone fart arsing about in the road.

Do you brake to a complete stop as fast as you can possibly manage (Which is what the prosecution are saying you should do to avoid such) at the mere sight of someone potentially going to cross the road or is in the process of crossing the road, either in car or on bike when a fair few metres away?  99.99999% of all situations for all types of road user that would be an absolute no.

he had two lots of thinking to do, the first when he first acknowledged the hazard and braked, that takes up 1.5seconds thinking time for the unexpected situation plus a bit for mechanical action time.

When the deceased failed to get her shit together and cross in a normal fashion as would be expected he would have had yet another set of decisions to make (another 1.5s thinking time for the unexpected step back into him). At this point that is the 3.8sec from her stepping out and thus he had no time to brake further because at 10mph (A slow speed remember, she moves back into him).

Therefore unless you ask every single road user to come to a complete stop every time someone makes a move toward a crossing or a motor, cycle, equine, invalid carriage  etc comes to a junction, rounabout you have priority just in case they do the unexpected, then you cannot find the convicted rider of a slow moving bicycle guilty of wanton and furious riding because the law/justice system will not instist on the exact same set of values/responsibilities/actions for all those groups in any given scenario.

We know this already because those rules have being breached time and time and time again with the death of pedestrians and people on bikes by motorists with naught but a slap on the wrist if even any case to answer.

 

The point is that once the decision was made to brake he was not able to reduce his speed as effectively without a front brake.

That is undeniable.

Pedestrians do unpredictable things, you've previously advocated for motorists remaining vigilant in case of people unexpectedly entering the road.

How is this case any different?

If you're in an area with a lot of pedestrians reduce your speed and cover your brakes, it's just common sense.

Rich_cb wrote:

BehindTheBikesheds wrote:

 

he DID brake, from approx 18mph to approx 10mph (A speed given by the prosecution as within the range of speed upon impact), a speed that you would know is a dawdle and as per pretty much everyone else would be fine to go around someone fart arsing about in the road.

Do you brake to a complete stop as fast as you can possibly manage (Which is what the prosecution are saying you should do to avoid such) at the mere sight of someone potentially going to cross the road or is in the process of crossing the road, either in car or on bike when a fair few metres away?  99.99999% of all situations for all types of road user that would be an absolute no.

he had two lots of thinking to do, the first when he first acknowledged the hazard and braked, that takes up 1.5seconds thinking time for the unexpected situation plus a bit for mechanical action time.

When the deceased failed to get her shit together and cross in a normal fashion as would be expected he would have had yet another set of decisions to make (another 1.5s thinking time for the unexpected step back into him). At this point that is the 3.8sec from her stepping out and thus he had no time to brake further because at 10mph (A slow speed remember, she moves back into him).

Therefore unless you ask every single road user to come to a complete stop every time someone makes a move toward a crossing or a motor, cycle, equine, invalid carriage  etc comes to a junction, rounabout you have priority just in case they do the unexpected, then you cannot find the convicted rider of a slow moving bicycle guilty of wanton and furious riding because the law/justice system will not instist on the exact same set of values/responsibilities/actions for all those groups in any given scenario.

We know this already because those rules have being breached time and time and time again with the death of pedestrians and people on bikes by motorists with naught but a slap on the wrist if even any case to answer.

 

The point is that once the decision was made to brake he was not able to reduce his speed as effectively without a front brake. That is undeniable. Pedestrians do unpredictable things, you've previously advocated for motorists remaining vigilant in case of people unexpectedly entering the road. How is this case any different? If you're in an area with a lot of pedestrians reduce your speed and cover your brakes, it's just common sense.

So slowing down to 10mph (admitted by prosecution) and diverting around the hazard is not being careful/vigilant in any ordinary circumstance? comparing to the actions of motorists in this instance is total and utter cobblers, motorists rarely show such consideration by comparison and still get off scott free.

As i said, would you yourself come to a complete halt as immediately as is physically possible (or even less than is pyhsically possible going by the prosecutions ridiculous/spurious claims) when a pedestrian is seemingly going to cross the road or does cross in front of you some distance away?

Well, do you, if not, why not? I don't need you to answer because I know full well that that would rarely if ever happen in the same circumstances that the convicted faced, I include myself and everyone else in that.

CygnusX1 wrote:

cyclisto wrote:

Wow where are all the boasters about road rim brakrs that we usually find in the technical threads?
So let's clear out things in braking:
2 wheels braking>front wheel only>rear wheel only
fresh tires>old tires
fat tires>skinny tires
slick tires>threaded tires
hydraulic disks>disks>v-brakes>calipers>rear wheel skid (unless you have the thighs of Sir Hoy)

Please finally accept the above if you haven't so already, because flat earthers exist everywhere.

You're wrong on two brakes being better than front alone. There is hard science behind this.

Yes I know, you know, in laboratory conditions with grippy tarmac, a good rider but who is simultaneously too bored to shift his weight behind the saddle, yes indeed you may equal braking distances with no rear saddle. But there is rain, slippery tarmac, skinny tires, people who don't have integrated brake assist in their hands like cars do, people who can shift their weight while braking and of course curves. So in real world conditions a rear brake is needed.

Don't be fooled though about my intentions, it is extremely idiotic to ride brakeless bike, in my opinion a bike with poor caliper brakes with worn skinny tires too, but city speed limits work in another way. Their concept is not that they are low so that drivers and riders may manage to stop, but so that when the inevitable collision happens, the pedestrian victims may survive. It is idiotic too trying to prove that in panic situation a rider can stop in 3m even more when we are talking about a bike/rider combo with minimal mass and therefore damage he may cause. Simply the victim was very very unlucky just like the people struck by lighting, eaten by a shark and so on.

madcarew wrote:

This is simply a tragic accident.

It is deeply unlikely that the speed Alliston hit Mrs Briggs contributed to her fatal injury. It seems very unlikely that even with a front brake that he would have avoided her.  Mrs Briggs injury was a fatal head injury caused largely by the speed and angle of her head hitting the ground from a fall. My friend's mother died 2 years ago after slipping on her bottom step and her head hitting the edge of the stairs. This caused a non-reversible head injury and she died 2 days later in hospital. From certain angles human heads are rather delicate (something that helmets try to assist with), and although Alliston hitting her certainly caused the fall, it is almost certain that there is almost nothing about Alliston's speed that caused the fatal injury. 

Complete nonsense.

If he hit her at 0.0001 mph do you think the outcome would have been the same?

Of course it wouldn't.

Therefore the speed he hit her at was a factor.

All the data on RTCs show that your chance of surviving a collision is inversely proportional to the speed that speed that the collision occurs at.

madcarew wrote:

This is simply a tragic accident.

It is deeply unlikely that the speed Alliston hit Mrs Briggs contributed to her fatal injury. It seems very unlikely that even with a front brake that he would have avoided her.  Mrs Briggs injury was a fatal head injury caused largely by the speed and angle of her head hitting the ground from a fall. My friend's mother died 2 years ago after slipping on her bottom step and her head hitting the edge of the stairs. This caused a non-reversible head injury and she died 2 days later in hospital. From certain angles human heads are rather delicate (something that helmets try to assist with), and although Alliston hitting her certainly caused the fall, it is almost certain that there is almost nothing about Alliston's speed that caused the fatal injury. 

I'm puzzled why there's no-one calling for mandatory helmets for pedestrians. Never mind the brakes on the bike - a helmet would have saved her life!

BehindTheBikesheds wrote:

So slowing down to 10mph (admitted by prosecution) and diverting around the hazard is not being careful/vigilant in any ordinary circumstance? comparing to the actions of motorists in this instance is total and utter cobblers, motorists rarely show such consideration by comparison and still get off scott free.

As i said, would you yourself come to a complete halt as immediately as is physically possible (or even less than is pyhsically possible going by the prosecutions ridiculous/spurious claims) when a pedestrian is seemingly going to cross the road or does cross in front of you some distance away?

Well, do you, if not, why not? I don't need you to answer because I know full well that that would rarely if ever happen in the same circumstances that the convicted faced, I include myself and everyone else in that.

You can't call for stricter sentencing when motorists kill vulnerable road users and not apply the same standards when cyclists do.

That's hypocrisy.

I would like to see manslaughter charges brought against motorists in similar situations.

The cyclist in this case took reasonable action once the lady stepped in front of him but those actions were insufficient to avoid a collision.

If he had even riding a legal bicycle his braking would have been superior and he could either have avoided the collision or it would have occurred at a much lower speed reducing the likelihood of harm.

I will reduce my speed quite substantially if there are pedestrians in the road ahead, I also keep an eye on the pavement for any pedestrians who look like they may be about to step out.

Will that prevent all collisions? Obviously not but if a collision does occur I will be able to say that I took all reasonable steps to avoid it.

The cyclist in this case could not do that due to the simple fact he was riding an illegal bicycle.

Applecart][quote=don simon wrote:

Quote:

The upshot of this case is that we should start to see more rigorous investigative work by the police and more custodial sentences for drivers.

 

How are drivers in any way related to this? The car is about a woman who lost her life and a cyclist on an illegal, non-roadworthy machine. This has fuck all to do with drivers!

Oh the irony of this comment when compared with nearly every story I've ever read about a cyclist and car incident. 

The only other person who is blamed as much for anything in the news is Donald Trump...who probably once rode a bicycle...

ChrisB200SX wrote:

According to the Highway Code, stopping distance at 20mph is 12m, half of that is thinking distance, 6m.
If he was doing 18mph and she stepped out 6.53m in front of him... well, I doubt I could have avoided colliding with her let alone grabbed both brakes first and shifted my weight back!
This whole anti-cyclist culture stinks.

That video clearly shows braking distance and not stopping distance.

There was a recent report stating that the thinking distance in the highway code is too low and we should allow atleast 1 second.

18 mph is a tiny bit more than 8 metres a second.

BTW I've long felt that speed limits should be in metres per second, not miles per hour. 30 mph is great, if you want to know how long it might take to drive one mile - but it gives no sense of speed. 13.4 metres in one second, on the other hand, does give a sense of speed.

Rich_cb wrote:

BehindTheBikesheds wrote:

So slowing down to 10mph (admitted by prosecution) and diverting around the hazard is not being careful/vigilant in any ordinary circumstance? comparing to the actions of motorists in this instance is total and utter cobblers, motorists rarely show such consideration by comparison and still get off scott free.

As i said, would you yourself come to a complete halt as immediately as is physically possible (or even less than is pyhsically possible going by the prosecutions ridiculous/spurious claims) when a pedestrian is seemingly going to cross the road or does cross in front of you some distance away?

Well, do you, if not, why not? I don't need you to answer because I know full well that that would rarely if ever happen in the same circumstances that the convicted faced, I include myself and everyone else in that.

You can't call for stricter sentencing when motorists kill vulnerable road users and not apply the same standards when cyclists do. That's hypocrisy. I would like to see manslaughter charges brought against motorists in similar situations. The cyclist in this case took reasonable action once the lady stepped in front of him but those actions were insufficient to avoid a collision. If he had even riding a legal bicycle his braking would have been superior and he could either have avoided the collision or it would have occurred at a much lower speed reducing the likelihood of harm. I will reduce my speed quite substantially if there are pedestrians in the road ahead, I also keep an eye on the pavement for any pedestrians who look like they may be about to step out. Will that prevent all collisions? Obviously not but if a collision does occur I will be able to say that I took all reasonable steps to avoid it. The cyclist in this case could not do that due to the simple fact he was riding an illegal bicycle.

This, and if Alliston has to do time in order to achieve it, I won't lose any sleep. The prosecution has given us the tools to do it. I would want this prosecution team in my corner if I were to be hit by a motorised vehicle.

joules1975 wrote:

Yorkshire wallet wrote:

It gets worse. Look at this nonsense from a BBC interviewee. Mr Lane, who rides a fixie himself with a front brake, suggested that bikes should have to be regularly serviced and checked, much like the MOT system for cars. Fuck that. MOT for bikes!! Imagine your local spanner monkey at halfords failing your bike for excessive dirt on running gear and requiring you to buy a new chain.

I think you're missing what an MOT is about. It's about testing to see if the vehicle is safe to be on the road, not whether it's running properly or even if it's correctly maintained (other being kept to a level of being safe).

You could go years without getting your car serviced and it might still pass the MOTs.

Therefore you could go years without replacing things like your chain on your bike or lubing/cleaning it correctly, but it could still be deemed safe if all the rights bits are tight, it has two working brakes and the tyres are pumped up (any bike MOT would be a bit more than that, but you get the idea).

Also, the thing with an MOT is that its a nationally defined test with clear guidelines, unlike the building/checking of a bike at your local shop (halfords or otherwise). Before anyone jumps on this, yes I know many mechanics are cytech certified - myself included - and that there are documentented approaches, but the point is they are not mandatory and applied rigorously.

In some ways an MOT for bikes is good idea, but the problem is that it will likely put many people off cycling, much like making helmets compulsary would.

I'm not surprised that the bloke from LMNH is backing the bike MOT though - don't they have repair/servicing workshops? It'd be a nice little additional money spinner.

I think that you are over estimating how effective MOT's are for motor vehicles. Certain areas are pretty good, but others not so much. There are lots of people in to car modification who put things back to how they should be for the MOT, then revert to the modified state as soon as they get their certificate. Even relatively normal enthusiasts of some top end manufacturers do things to their vehicles e.g. to improve the sound (temporary mod's to exhaust systems) or performance (plug in ECU box things) which would make a vehicle fail an MOT if left in the modified state.

If a similar test was introduced for bikes, they are even easier to mess around with. There would be nothing to stop your man in this instance from sticking a front brake on to the bike for an hour, then removing it as soon as it was certified. It would only take about 5-10 min's.

burtthebike wrote:

RedfishUK wrote:

I'm sorry but the ONLY valid test here would have been:-

The same bike with and without a front brake, any other test is meaningless

Almost right.  To be at least remotely valid, the same bike would have to be used, with a rider experienced in riding  both fixie and other bikes, but crucially, the test would have to be done multiple times, with the stop signal to the rider being random, so they wouldn't know whether they were stopping or not.  If they knew they were going to stop, the test is not realistic enough to be valid and it should have been challenged by the defence.

Almost right.  The biggest variable here, IMHO, is the road surface.  That video is on perfect tarmac - most cycles don't have suspension or shock absorbers or anti-lock brakes, the quality of the road surface makes a massive difference to braking distances.

You can apply a great deal more force on a perfect surface.  If you apply the same level of force to the front break lever on a poor surface and you hit a road defect, your front wheel may bounce up, when it lands it may lock and if it does, you may well go over the handle bars.

jh27 wrote:

BTW I've long felt that speed limits should be in metres per second, not miles per hour. 30 mph is great, if you want to know how long it might take to drive one mile - but it gives no sense of speed. 13.4 metres in one second, on the other hand, does give a sense of speed.

How many metres is it from Manchester to London? How many seconds would it take to get there?

In short... no.

Rich_cb wrote:

You can't call for stricter sentencing when motorists kill vulnerable road users and not apply the same standards when cyclists do.

That's hypocrisy.

Is it?

When a cyclist and pedestrian collide, and someone dies - what percentage of those who die are pedestrians and what percentage are cyclists.  I know of two recent case where a cyclist and a pedestrian and who stepped into the road have collided, in one case (this case) the pedestrian died, in the other, it was the cyclist.

When a motorist and pedestrian collide, what percentage of motorists die?

How many pedestrians die from a slip/trip/fall without colliding with anyone?

I try to be a cautious as is practical when cycling around pedestrians,  but primarily for my own safety as I know that I stand a good chance of coming off worse from any collision.  When I drive, I primarily drive safely to avoid injury to others.

Operating a motor vehicle caries much less risk to the driver, which is why they have much greater responsibility.

vonhelmet wrote:

jh27 wrote:

BTW I've long felt that speed limits should be in metres per second, not miles per hour. 30 mph is great, if you want to know how long it might take to drive one mile - but it gives no sense of speed. 13.4 metres in one second, on the other hand, does give a sense of speed.

How many metres is it from Manchester to London? How many seconds would it take to get there?

In short... no.

That is exactly my point.  Speed limits do not exist to inform road users of journey times.  They exist to enforce and inform road users' safety.  Knowing how long it takes to drive from Manchester to London has no impact on road safety.

As an aside, the last time I drove to Manchester, the average speed was about 20 mph, with large sections of it being travelled on the M6 at less than 5 mph.

jh27 wrote:

Is it?

 

When a cyclist and pedestrian collide, and someone dies - what percentage of those who die are pedestrians and what percentage are cyclists.  I know of two recent case where a cyclist and a pedestrian and who stepped into the road have collided, in one case (this case) the pedestrian died, in the other, it was the cyclist.

 

When a motorist and pedestrian collide, what percentage of motorists die?

 

How many pedestrians die from a slip/trip/fall without colliding with anyone?

 

I try to be a cautious as is practical when cycling around pedestrians,  but primarily for my own safety as I know that I stand a good chance of coming off worse from any collision.  When I drive, I primarily drive safely to avoid injury to others.

 

Operating a motor vehicle caries much less risk to the driver, which is why they have much greater responsibility.

Yes it is.

If you drive a defective car you're putting both yourself and other road users in danger.

Ditto for a defective bike.

A defective bike may not be as dangerous as a defective car but it can still be fatal.

That is the crux of the matter, a man rode an illegal bike and a lady died in a collision with that bike.

Had the bike been legal the collision would have either not occurred or occurred at much lower speed reducing the likelihood of injury.

jigr69 wrote:

If the prosecution are correct in saying that the deceased was 6.35 metres away from the cyclists when she stepped out into the road, the thinking distance alone at 20mph is 6 metres. So if we call it 5.35 metres from 18mph, gives the guy 1 metre braking distance. Even by the Police standards, he still would have hit the woman at some speed.

It took the Police 3.1 metres from 15mph to stop, so 5mph per metre. In the one metre he had to stop, he reduced his speed by up to 8mph and by a minimum of 4mph. This is entirely in line with the results of the Police video using two brakes.

He wasn't cycling a defective bike which has been mentioned when it comes to comparing cars and bikes, the bike was perfectly okay. It wasn't appropriate nor legal to be on the road as the law states that a bike needs two means of stopping, although there are caveats. For example, you can ride a penny farthing legally on the road without any brakes, but if you have a trike, the rear brake must act upon both rear wheels. However for a recumbent bike, the rules are unclear as the need for two brakes is designated by the height of the seat (needs to be above 635mm above the ground). Who reading this knew that?

He had time to shout out twice before the impact therefore he had time to brake.

The bike may have been 'OK' by your definition but it was illegal and incapable of stopping as quickly as an equivalent legal bicycle.

davsear wrote:

I think a lot of people are missing the point here. Whether he could have stopped in 3m or 12m, having a front brake fitted would have undoubtedly slowed and softened the impact between cyclist and pedestrian and this whole situation could have been avoided. That to me is what the police video highlights.  

Are you saying that you could have predicted the injuries/result had Alliston been moving at a lower speed?

Who could have predicted a death at 18mph?

This wasn't an accident (both could have done something to avoid it), but the consequences couldn't have been predicted though. Nor could they have at 15mph, 10mph or even 0.0001mph.

Point not missed.

Rich_cb wrote:

He had time to shout out twice before the impact therefore he had time to brake. The bike may have been 'OK' by your definition but it was illegal and incapable of stopping as quickly as an equivalent legal bicycle.

The bike was perfectly okay in any sense of the definition, but wasn't legal to be where it was, don't think any disputes that fact. That is something that everyone agrees on. The guy is also an idiot for doing so, likewise his comments afterwards didn't help the situation.

Muscles take longer to react and enact than a mouth does to say anything. 

When cycling and driving if an obstacle suddenly appears infront of you, your first thought is, can I avoid it. If you cannot avoid it, then stopping and hoping for the best is the next and last resort. That is called the reaction time since in the process of that thinking etc, you car or bike is still moving forward.

If he had a front brake, he would still have to move his hands onto the brake after his thought process had gone through the process. A roadie on the tops or drops would have to do the same.

Have you ever seem two people walking down the street, try to avoid each other and end up bumping into each other? They didn't just stop dead, but tried to avoid the issue by going around the obstacle, if the other person does precisely the same but in the opposite direction, you are still on a collision course. Sometimes this happens two or three times with one person normally commenting about having a dance.

He saw the deceased, tried to avoid her by going on the inside of her, between kerb and her, but she stepped back and they collided. A tragic accident, yes. An unavoidable one, I don't think so.