Home
Police claimed fixed-wheel rider could have stopped in 3 metres to avoid collision with Kim Briggs if he’d had front brake – but is that feasible?

 

The Metropolitan Police have released a video that they claim shows comparative stopping distances between a police mountain bike equipped with front and rear brakes, and one with no brakes at all.

The video was made public alongside a press release issued yesterday following the conclusion of the trial at the Old Bailey of cyclist Charlie Alliston.

But it raises a number of questions about the methodology used by the Met to conduct their stopping distance tests.

• Was the police rider an experienced fixed gear cyclist? A number of those who have watched the police video suggest the rider in the video does not appear to be experienced at riding that type of bike.

• Did the police test Alliston's bike with and without a front brake to find out what the exact difference in stopping distances would have been?

• Did they test another rim braked bike with thinner road tyres? The police bike is heavier and has fatter tyres which should help it stop in a shorter distance than a lighter bike with thinner tyres.

• Did the police perform multiple runs to establish an average stopping distance?

Alliston, aged 20 and from Bermondsey, was acquitted yesterday of the manslaughter of 44-year-old Kim Briggs, who died from head injuries sustained as the pair collided on London’s Old Street.

However, he was found guilty of causing bodily harm by wanton and furious cycling, and could face jail when he is sentenced next month, with the offence carrying a maximum penalty of two years’ imprisonment.

> Charlie Alliston cleared of manslaughter of Kim Briggs but convicted of wanton and furious driving

It is unclear whether the video released by the Metropolitan Police is the same as one shown to a jury at the trial last week, and we are seeking clarification on that issue and the others raised above. As at the time of publication of this article, we had not received a reply.

During the trial, the Crown did not dispute that Mrs Briggs had stepped out into the road in front of Alliston.

Instead, one of the central pillars of their case was that his bike – a fixed-wheel Planet X track model – did not have a front brake.

Not only did that mean it was not legal for use on the road, but it was argued that if it had been equipped with one, he may have been able to stop in time, or at least that the collision, during which their heads clashed, would have been less severe.

While Alliston was described in court as a former courier – more recently, he has been working as a scaffolder – it is unclear how experienced or skilled he was at riding a fixed-gear bike, although it appears he had been doing so for at least a year before the fatal collision.

Caspar Hughes, who is on the co-ordinating group of campaign organisation Stop Killing Cyclists, told road.cc: “If Charlie Alliston had a front brake Kim Briggs might still have been here regardless of whether she looked before she walked out or not.

“But this terrible case highlights the double standards in how the national press report fatalities by drivers compared to people riding bikes.”

Hughes is a highly experienced fixed-wheel bike rider. He spent a decade as a cycle courier in London, before founding roller racing business Rollapaluza, which celebrates its tenth birthday this week.

We asked him his opinion of the distance it took the second cyclist to stop in the video.

He said: “It is hard to gauge how experienced the rider in the police video is at bringing his bike to a dead stop, but I know I can bring my bike to a halt much quicker than he did using nothing but the drive train.”

Evidence presented by the police at the trial suggested that Alliston had been riding at 18mph and was 6.53 metres from Mrs Briggs when she stepped into the road.

It was claimed that his braking distance was 12 metres but would have been 3 metres had his bike had a front brake fitted – something that Martin Porter QC, writing in the Guardian Bike Blog, said “is frankly absurd.”

Porter, a club cyclist and cycling advocate who has represented cyclists and their families in a number of cases, said that based on a formula in the book Bicycling Science by MIT emeritus professor David Wilson, the stopping distances here would have been 13.5 metres with no front brake, and 6.5 metres if one were fitted.

It’s worth noting, though, that in the police video, the first bike is indeed shown stopping after 3 metres, albeit from a slower speed of 15mph, and it is a different kind of bike to the one Alliston was riding and has two brakes.

Porter also made the point, as others have done, that the braking distance for a car being driven at 20mph – the location where the crash happened – is 12 metres, according to the Highway Code, and that in those circumstances, as well as in this case, reaction time also needed to be factored in.

> Husband of woman killed by cyclist calls for changes to law on dangerous cycling

Born in Scotland, Simon moved to London aged seven and now lives in the Oxfordshire Cotswolds with his miniature schnauzer, Elodie. He fell in love with cycling one Saturday morning in 1994 while living in Italy when Milan-San Remo went past his front door. A daily cycle commuter in London back before riding to work started to boom, he's been news editor at road.cc since 2009. Handily for work, he speaks French and Italian. He doesn't get to ride his Colnago as often as he'd like, and freely admits he's much more adept at cooking than fettling with bikes.

81 comments

Avatar
don simon [1539 posts] 3 months ago
12 likes
Quote:

• Was the police rider an experienced fixed gear cyclist? A number of those who have watched the police video suggest the rider in the video does not appear to be experienced at riding that type of bike.

• Did the police test Alliston's bike with and without a front brake to find out what the exact difference in stopping distances would have been?

• Did they test another rim braked bike with thinner road tyres? The police bike is heavier and has fatter tyres which should help it stop in a shorter distance than a lighter bike with thinner tyres.

• Did the police perform multiple runs to establish an average stopping distance?

Oh good, another Alliston thread, but here we go.

Are all rim brakes the same?

Do the police do similar tests on motorised vehicles?

Do the police climb all over trucks just to see what the blind spot is?

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.

 

Avatar
brackley88 [170 posts] 3 months ago
14 likes

That's a ridiculous comparison. 

They could at least have got a fixie with thin tyres and brakes and get an experienced fixie rider to stop with the brakes, remove them and do without. The guy stopping is clearly not experienced...where was the oh so cool skid?

Avatar
durandal [15 posts] 3 months ago
2 likes
don simon wrote:

Do the police do similar tests on motorised vehicles?

Yes

don simon wrote:

Do the police climb all over trucks just to see what the blind spot is?

Yes

don simon wrote:

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

Fatal accidents are rigorously investigated. Sentencing is a matter for the courts and the law, and outwith the gift of the police investigation.

 

 

Avatar
don simon [1539 posts] 3 months ago
7 likes
durandal wrote:
don simon wrote:

Do the police do similar tests on motorised vehicles?

Yes

don simon wrote:

Do the police climb all over trucks just to see what the blind spot is?

Yes

don simon wrote:

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

Fatal accidents are rigorously investigated. Sentencing is a matter for the courts and the law, and outwith the gift of the police investigation.

 

 

So why don't they publicise it like what they done here?

Avatar
Zjtm231 [92 posts] 3 months ago
8 likes
durandal wrote:
don simon wrote:

Do the police do similar tests on motorised vehicles?

Yes

don simon wrote:

Do the police climb all over trucks just to see what the blind spot is?

Yes

don simon wrote:

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

Fatal accidents are rigorously investigated. Sentencing is a matter for the courts and the law, and outwith the gift of the police investigation.

 

 

If all fatal acidents are "rigorously investigated" this way then they are obviously an utter shambles....

Avatar
SteveAustin [76 posts] 3 months ago
6 likes

like it posited on the other thread. no comparsion between a mtb and a fixie with 1 brake. not a fair comparison at all.

i can almost guarantee i would not be able to stop a roadbike within 3m with two good brakes. Road tyres do not grip the road under heavy braking, they skid, they have always done this, they always will. once the wheel is locked up, that really small contact patch is not enough to stop, it just loses traction and slides. The only other option on a roadbike, with two brakes, is to hard brake the front wheel and try to control the lift of the rear wheel. do this in 3m? never

The whole scenario is a joke.

Avatar
RedfishUK [159 posts] 3 months ago
23 likes

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

 

Avatar
Zjtm231 [92 posts] 3 months ago
10 likes
  • The surface was also looks damp in the police video - was it?
  • What weight was the rider?
  • What was the weight of the bike(s)?
  • What were the bikes made of?
  • What width and make of tyres were either/both of the test bikes running?
  • What were the brakes on the mountain bikes? Rim or disc?
  • The rider in the video is clearly not braking properly for a fixie rider. With no skidding whatsoever.

Almost certainly such different factors as to be totally inconsistent and therefore should not have been admissible in court.

Unbelievable this “evidence” wasn’t challenged by the defence but it seems it wasn’t…

 

Also I have read it was “established” in court she wasn’t “distracted” by her mobile phone – yet still seemed to have it in her hand.  This doesn’t seem to have been challenged by the defence?! Who the hell was defending him?

Avatar
ChrisB200SX [565 posts] 3 months ago
8 likes

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.

Avatar
kevinmorice [146 posts] 3 months ago
8 likes

If that was used in evidence against me I would be laughing all the way to freedom. The Met should be ashamed that they put that video out. 

Avatar
joules1975 [485 posts] 3 months ago
0 likes

No question the video looks a bit crap

  • for start, what was it filmed on? A first gen smart phone? The image quality is crap.
  • the fact that the two bike were different in more ways than just the front brake doesn't lend itself to a good test.

However, the first bike is not a mountain bike, it's a fixie with flat bars. It might have wider tyres but we have no idea.

The rider doesn't look like a complete novice, but probably not that experienced (a novice would have been crapping themselves if my experience of riding a fixie is anything to go by). However, who's to say that everyone on a fixie knows how to/has ability to lock the rear wheel, and in any case, as any self respecting kid will tell you, locking the rear wheel doesn't help you slow down particularly quickly - all it does it give you a massive skid.

In the video thinking distance is not considered, but it may have been during the court procedings.

We have no idea if this was challenged in court or not - hopefully it was but in my view riding without a front brake is stupid and therefore no surprise that they prosecuted him.

Regardless of all that, if the the media reports are at least partially based on fact, the guys attitude probably hasn't helped matters, and may have played a big part in the reason for the conviction.

Ultimately though we can type whatever we like but it's all pretty meaningless, as without the court transcripts, we don't really have a clue what's gone down.

 

Avatar
cyclisto [331 posts] 3 months ago
0 likes

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.

Avatar
Rich_cb [471 posts] 3 months ago
3 likes

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.

Avatar
alansmurphy [1212 posts] 3 months ago
5 likes

A Bugatti Veyron stops more quickly than a Renault Clio from the same speed. I think we should ban all cars that fall below this standard.

Well done MET. They really are making quite a significant rod for the motorists back aren't they...

Avatar
Colin Peyresourde [1820 posts] 3 months ago
4 likes

As far as I understand it Charlie Alliston was riding a bike which did not have a front brake, which is illegal to use on the open road.

At the time of the incident it is said he was doing 18 mph. 

He collided with Kim Briggs, who had walked out into the road without seeing him. He tried to slow or stop his bike and avoid the individual, yelling at the Kim. Unavoidably they collided, and in the resulting collision Kim hit her head badly and died from this injury.

Sadly, we don't know if having a front brake would have changed the outcome for Kim.

Alliston's personal lack of contrition has made him look very callous in all of this - and his attitude in not accepting blame for this tragic accident has made him a pariah.

But if his crime is being in a fatal accident and having a vehicle that was not road worthy a lot more motorists should consider themselves lucky.

Avatar
Applecart [78 posts] 3 months ago
1 like
don simon]<p>[quote wrote:

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!

Avatar
davel [1971 posts] 3 months ago
7 likes
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!

You forgotten which bridge you live under again?

Avatar
Yorkshire wallet [1569 posts] 3 months ago
4 likes

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.

Avatar
ktache [627 posts] 3 months ago
6 likes
durandal wrote:
don simon wrote:

Do the police do similar tests on motorised vehicles?

Yes

don simon wrote:

Do the police climb all over trucks just to see what the blind spot is?

Yes

don simon wrote:

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

Fatal accidents are rigorously investigated. Sentencing is a matter for the courts and the law, and outwith the gift of the police investigation.

 

 

I seem to remember in a certain case a police investigator claiming that a motorist could not be expected to react within 5 seconds.

 

Avatar
CygnusX1 [631 posts] 3 months ago
4 likes
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.

Avatar
don simon [1539 posts] 3 months ago
15 likes
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!

'Cos both cyclists and drivers use the same fucking roads, with the same fucking rules. 'Cos a fucking driver can kill and get a few points for careless driving while an equally carefuckingless cyclist is charged with manslaughter.

Get the fuck with it.

OK?

Avatar
joules1975 [485 posts] 3 months ago
1 like
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.

Avatar
rliu [121 posts] 3 months ago
4 likes
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.

Any half competent person should be able to check that they have two brakes and inflated tyres. Now unless this proposed MOT has carbon frame X-raying thrown in for less than £50 I'm dead against it.

Avatar
FluffyKittenofT... [1889 posts] 3 months ago
8 likes
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.

Next: Timpson's call for compulsory shoe-inspections for pedestrians.

Avatar
Flying Scot [1005 posts] 3 months ago
4 likes

That test is ridiculous and surely cant be the basis of a safe prosecution.

And while they're at it, what about an MOT for horses and careless walking being an offence.

Avatar
freespirit1 [258 posts] 3 months ago
8 likes

Alliston was riding a bike that was illegal to use on the road.

 

He (unintentionally) killed someone whilst using illegal machine.

 

Car driver (unintentionally) kills someone whilst using an illegal machine.

 

Both should expect jail time the length of which is up to the judge and the sentencing guidelines.

 

 

Avatar
burtthebike [1219 posts] 3 months ago
6 likes
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.

Avatar
Beecho [213 posts] 3 months ago
5 likes

When in Dallas a few years back, I went to the book depository to test if a sniper could have shot JFK from there by dropping a load of napalm on the street below.

Avatar
Jitensha Oni [97 posts] 3 months ago
2 likes
Colin Peyresourde wrote:

As far as I understand it Charlie Alliston was riding a bike which did not have a front brake, which is illegal to use on the open road.

At the time of the incident it is said he was doing 18 mph. 

He collided with Kim Briggs, who had walked out into the road without seeing him. He tried to slow or stop his bike and avoid the individual, yelling at the Kim. Unavoidably they collided, and in the resulting collision Kim hit her head badly and died from this injury.

Sadly, we don't know if having a front brake would have changed the outcome for Kim.

Alliston's personal lack of contrition has made him look very callous in all of this - and his attitude in not accepting blame for this tragic accident has made him a pariah.

But if his crime is being in a fatal accident and having a vehicle that was not road worthy a lot more motorists should consider themselves lucky.

good summary - maybe could be modifed to "reported personal lack of contrition" - in view of their past record, why should we give the MSM the benefit of doubt over their accuracy of reporting of the emotional aspects?

Avatar
janusz0 [70 posts] 3 months ago
2 likes

What would help our understanding would be if the journalists who attended day 1 in court, had also reported on the next 4 days, until the jury was sent out. We're missing a lot of information from the trial and have no idea how the defence was conducted.

Pages