red lights

Mark Thompson said:

Quoted message said:

What exactly is being counted in your suggestion? The
proportion of cyclists visiting representative sites who
offend? Or the proportion of only those who have an
actual /opportunity/ to offend that do so? The former is
not what I want to know. The latter would mean difficult
and subjective judgments for the researcher.

What about setting up shop on a T junction, and
counting those that travel left to right aross the bar.
Jumping a light like this should be easily possible and
one of the safest lights to jump, so we can assume that
a 'jumper' will always have the opportunity and will
reveal himself here.

They don't. That's actually a blatent type of jump in terms
of being seen by others, so quite a few cyclists that would
jump elsewhere, quietly, don't jump there. It' not just
about safety, it's about being seen to do the "wrong" thing.
It's not always safe (or convenient for others) to go ahead
anyway. And the jumper will not have the opportunity if
anything in front is blocking his/her way to proceed. That's
not straightforward to judge objectively. "Would they
normally go through that little gap even if the light was
green or are they waiting there just because the light is
red?", etc. To average all this behaviour out, I think you
need to sample the same cyclist over a number of junctions.
Otherwise I think you're researching the junction instead of
the cyclists.

Quoted message said:

Anyone waiting is either not a jumper, or knows that the
light is going green very soon. Given the relative safety
in which this type of junction can be crossed at red, it
is IMO likely that jumpers will go for it however small
the delay.

There are jumpers and there are jumpers.

~PB

Roos Eisma said:

Ideally you want a mix of methodologies to fully
understand what's going on. Statistics from a single
crossing. Statistics from individual cyclists. Different
times of day, year, weather. In-depth interviews with a
cross section of people.

That would be great. I can't do all that, though!

Quoted message said:

Erm - what was the originial research question exactly?

What proportion of cyclists jump fewer than one red traffic
light per two miles of cycling in inner London?

Quoted message said:

Though I'm normally not a red light jumper I sometimes
make an exception for the pedestrian crossing on Blackness
Road, if I can see the ped who pushed the button has
already crossed before it turned red and there isn't
another ped in sight.

I hate to tell you this but I think you're perfectly normal
:-) ...and reasonable.

~PB

Pete Biggs said:

That's only one of the minor problems. The major one is
judging what counts as a fair opportunity to offend.

But you have exactly the same problems if you're following
them rather than just stood nearby.

Quoted message said:

Yes I know that but it doesn't matter how large the sample
base is unless you're sampling the necessary information.

Same again, you have the same problems following.

Quoted message said:

It is a risk but only a small one in practice because they
tend not to /see/ the the following cyclist if he keeps
his distance

But the more you keep your distance the less you are in a
position to make the judgments you outline above. You can't
win, in other words!

Quoted message said:

To answer my question, the necessary recording and
computation would be extremely complex with this method.

Recording is more bothersome the more you do, but not
necessarily the computation. Most data processing is simply
discarding the stuff that doesn't need looking at, but
having it there means you've got it for other, probably
related questions, when you need to ask them.

Quoted message said:

It's no good getting loads of samples if you can't sort
out all the other problems.

Quoted message said:

I only need to see one cycle at a time.

But you need to see it in such a way that you can answer the
questions you say are a problem with observing junctions. I
really don't see how riding your bike a way behind gives you
a better chance of answering these properly.

Pete.
--
Peter Clinch Medical Physics IT Officer Tel 44 1382 660111
ext. 33637 Univ. of Dundee, Ninewells Hospital Fax 44 1382
640177 Dundee DD1 9SY Scotland UK net
[email hidden] dundee.ac.uk~pjclinchOpen ↗

Pete Biggs said:

What proportion of cyclists jump fewer than one red
traffic light per two miles of cycling in inner London?

This is a rather contrived and limited question though, with
the answer of rather limited use. The point of a big dataset
is you can ask more than one question of it.

Pete.
--
Peter Clinch Medical Physics IT Officer Tel 44 1382 660111
ext. 33637 Univ. of Dundee, Ninewells Hospital Fax 44 1382
640177 Dundee DD1 9SY Scotland UK net
[email hidden] dundee.ac.uk~pjclinchOpen ↗

Peter Clinch said:

Pete Biggs said:

That's only one of the minor problems. The major one is
judging what counts as a fair opportunity to offend.

But you have exactly the same problems if you're following
them rather than just stood nearby.

Good, now we're getting to the crux. The following is the
main reason for my method:

I don't have to make such (fine) judgements if the cyclists
is given an ample number of sites to offend at because they
are highly likely to get at least one opportunity by
default. There would be loads of traffic lights on an
average follow if starting from a road with traffic lights.

I'm suppose the same could be done with your method but I
still think that would require finer judgement and overly
complex calculations, using unreliable factors.

The flaw in my method (and I think the only major one) is
where the cyclists turns off the main roads and stays on side-
roads with no traffic lights. I wouldn't mind including
those cases.

[rest snipped because the above is my answer to it]

~PB

Peter Clinch said:

Quoted message said:

What proportion of cyclists jump fewer than one red
traffic light per two miles of cycling in inner London?

This is a rather contrived and limited question though,
with the answer of rather limited use.

I agree it's of limited use but it's a question I would be
fascinated to learn the answer to.

Would you not be even a little interested to know the answer
yourself, or would you rather not want to know if how many
cyclists broke this law? Or not want it to be known? It is
at least interesting to know how many people are on the
receiving end of the zero-tolerance bregade's criticism.

Quoted message said:

The point of a big dataset is you can ask more than one
question of it.

I don't deny that. But sometimes more indepth research into
indiduals is more revealing than what one person with
limited resources can do with big-dataset type research.

~PB

Pete Biggs said:

Would you not be even a little interested to know the
answer yourself, or would you rather not want to know
if how many cyclists broke this law? Or not want it to
be known?

I'd be a little bit interested, but then probably far /more/
interested in answers to followup questions which the data
wouldn't answer!

Have you got in touch with LCC about this? They may well be
interested themselves (or maybe even done something similar
themselves), plus have more man-hours at their collective
disposal than you to implement a survey.

Pete.
--
Peter Clinch Medical Physics IT Officer Tel 44 1382 660111
ext. 33637 Univ. of Dundee, Ninewells Hospital Fax 44 1382
640177 Dundee DD1 9SY Scotland UK net
[email hidden] dundee.ac.uk~pjclinchOpen ↗

Peter Clinch said:

Have you got in touch with LCC about this? They may well
be interested themselves (or maybe even done something
similar themselves), plus have more man-hours at their
collective disposal than you to implement a survey.

No I only thought up the idea last week so I'm still just
thinking/experimenting about the method. Thanks for the LCC
suggestion. That's a good one.

~PB

Peter Clinch said:

IYSWIM

Indeedy

James

On Thu, 3 Jun 2004 11:22:20 +0100,

Pete Biggs p@melonbiggs{remove said:

What proportion of cyclists jump fewer than one red
traffic light per two miles of cycling in inner London?

My London commute is 2.5miles. 16 lights on the way to work
of which approximately half are red and I have to stop (or
slow dramatically) (I've only been counting for three days)
On my commute to work it is rare for me to see a cyclist who
does jump a set of lights (whether I'm cycling at 7.15 or
9.15 makes no odds) On my return journey I would guess about
half of the cyclists I see do jump lights (and I jump one
set that won't change - bus lane, no taxis so it is
presumably set to just trigger when a bus comes along)

I see far more cars jumping red lights. Maybe not as a
proportion of total cars but once one car has stopped it is
hard for the car behind to jump the lights.

The lights at the cross roads where the busses exit Euston
Station seem to be completely optional for cars travelling
south. Today the southbound cars were still crossing the
red lights after the bus exit had gone to green, back to
red and then the road opposite the bus exit had gone to
green - the cars eventually stopped after I forced my way
out although even then I'm not sure whether they had really
stopped or just left a gap big enough for a bike to get
across the box junction.

(I have actually began to wonder whether these lights are
faulty. I can see the red light on the other side of the
crossing for the cars but not the light on their side. And
this happens almost every day. Maybe one is green and the
other red)

Tim.

--
God said, "div D = rho, div B = 0, curl E = - @B/@t, curl H
= J + @D/@t," and there was light.

tjw.hn.orgtjw.hn.orgOpen ↗
locofungus.btinternet.co.uklocofungus.btinternet.co.ukOpen ↗

On Thu, 3 Jun 2004 02:01:51 +0100, "Pete Biggs" <pmelon{remove
[email hidden]> wrote (more or less):

Quoted message said:

"Dave Kahn" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

It's not poor. It will be statistically significant if
you follow enough people. Where bias might creep in is in
selecting the subjects to follow. You need to have an
objective repeatable method.

Thanks Dave. I appreciate the difficulty with selecting
subjects and the whole thing being objective. This has can
only be an informal non-scientific thing, for me, then --
just some glorified anecdotal evidence gathering.

I'm thinking of simply following anyone who happens to be
the next nearest cyclists to me wherever I am, whoever they
are, following on with the next cyclists ASAP after I'm
finished with them. I'm fast enough to keep up with nearly
everyone who rides a bike in inner London, but those who
are too fast (or reckless) will be excluded by default.
Otherwise I'd stop after the distance limit was up or a red
light jumped.

The key problem that separates your approach from an
objective study is that you are selecting your sample,
rather than geting it randomly.

Quoted message said:

Also excluded are pavement cyclists, and maybe pedicabs (?
not sure: they're so incredibly slow ...and different).

I've tried this out a bit already and it's a recipe for the
most random bike rides I've ever done.

~PB

--
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links (harvested from comp.lang.smalltalk)
html.dnsalias.netsmalltalkOpen ↗

Gawnsoft wrote:

I said:

Quoted message said:

I'm thinking of simply following anyone who happens to be
the next nearest cyclists to me wherever I am, whoever
they are, following on with the next cyclists ASAP after
I'm finished with them. I'm fast enough to keep up with
nearly everyone who rides a bike in inner London, but
those who are too fast (or reckless) will be excluded by
default. Otherwise I'd stop after the distance limit was
up or a red light jumped.

The key problem that separates your approach from an
objective study is that you are selecting your sample,
rather than geting it randomly.

As I explained in my above paragraph, the idea is that I
won't be picking someone out from the middle of a crowd or
waiting for the "right" kind of cyclist to come along. It'll
be whoever is the next on-road cyclist nearest to me at the
session start place & time and after each follow has ended,
so the sampling will be virtually automatic and the
selection will effectively be random. However, you will
indeed only have my word for it, so:--

...I repeat:

Quoted message said:

Quoted message said:

This has can only be an informal non-scientific thing,
for me, then -- just some glorified anecdotal evidence
gathering.

~PB

On Sat, 5 Jun 2004 01:05:03 +0100, "Pete Biggs" <p@melonbiggs{remove
fruit}.tc> wrote (more or less):

Quoted message said:

those who are too fast (or reckless) will be excluded by

Quoted message said:

Quoted message said:

default.

As you explained in your paragraph.

i.e. you're selecting your group systematically.

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Gawnsoft said:

Quoted message said:

those who are too fast (or reckless) will be excluded by

Quoted message said:

> default.

As you explained in your paragraph.

i.e. you're selecting your group systematically.

Yes fair enough, but I still think it'll end up pretty
random. There should be few exclusions, but I'll see.

~PB