On 12/09/2017 01:28, TMS320 wrote:
On 11/09/17 10:33, JNugent wrote:
On 11/09/2017 10:12, TMS320 wrote:

On 09/09/17 21:29, JNugent wrote:
On 09/09/2017 12:40, TMS320 wrote:
On 09/09/17 00:39, JNugent wrote:
On 09/09/2017 00:32, TMS320 wrote:
On 08/09/17 13:39, JNugent wrote:
On 08/09/2017 11:39, TMS320 wrote:

Perhaps what is needed to reduce close passes outside shop
doors are obstructions on the pavement, such as plant
troughs... or free to use bicycle pumps.

Or occasional cattle grids, arranged longitudinally in line
with the direction of pedestrian travel.

Possibly, though putting something down with no purpose other
than to trap and cause harm might be rather harsh.

The purpose would *not* be to trap or harm anyone. Everyone
already knows that cycling is not permitted on footways and in
other pedestrian-only areas.
Preventing cycling along footways by physical means is no
different in principle from placing obstacles to prevent
motor-vehicles with three or more wheels from being driven onto
footways or into specified pedestrian zones.

I have not yet seen an obstacle for motor vehicles that intentionally
traps the wheels.

The Denver Boot makes a fair attempt at it.

They can't be fitted to a moving vehicle.

True.

But there are other built-in traps which dole out damage to vehicles
which is usually disproportionate to the "offence" being deterred.
Those "rising bollards" used for controlling access to urban pathways
for buses and delivery vehicles, for instance, have been known to do
severe damage to bodywork and floorpans. There have been a few
internet videos of such incidents. They are, at the very minimum, at
least analogous to cattle-grids. And probably more dangerous to humans.

I have seen these and very amusing it is too. When the bollard is up it
is just a bollard.

The salient point is that they are analogous to cattle grids for
deterring footway cyclists.

If you want prevention you stop or discourage people from going
where you don't want them to go. Prevention is not about harming
them if they go there.

No-one will harm them.
They might harm themselves, just as they will if they try to cycle
through a locked gate, or a brick wall.

The primary purpose of such things is not to trap or cause harm.

Quite right; it's a secondary effect. And the primary purpose of a
cattle grid placed inline on a footway would be to deter cycling on
that footway. Not different in principle to a "kissing gate or to the

The principle of operation is quite different.

I agree. The rising bollard requires actual planning and intention to
cause harm and physical danger in order to "work". If it were not so,
they would be designed so as not to "rise" under an obstruction of any sort.

obstacles which are to be found in the Greenwich *Foot* Tunnel in a
vain attempt to get cyclists to behave lawfully.

I bet you have absolutely no idea about what happens there.

Right now, today?

You're right.

What's happening?

In general though, one can make an educated guess, since the FOOT Tunnel
is (for some reason) a link between two discrete parts of some cycling
route or other. And the authorities have found it necessary to install this:

http://s0.geograph.org.uk/geophotos/03/87/48/3874825_1cc0913a.jpg

Your suggestion is rather like fitting RPGs to speed cameras.

Not in the slightest.

Harm from a speed camera mounted RPG would only be self inflicted.

Please describe the triggering and logic systems, detection process,
rocket-propulsion and warhead strength in some detail, together with
the anti-error provision. How many nearby pedestrians woild be killed
with each firing and what level of collateral damage to other vehicles
and buildings would have to occur for it to be unacceptable to you?

Putting it forward as the equivalent to your idea does not mean it has
to be designed and implemented.

TRANSLATION: "Yes, it was a daft suggestion, wasn't it?".

Sensible people would not oppose that measure in either case.

Sensible people can have fantasies... but know when they are fantasies.
Is your idea fantasy or practical?

Cattle grids are highly practical. To my certain knowledge, they're in
use all over the UK and probably elsewhere. They work.

Many people that don't ride bicycles aren't sensible about
cycling.

You said it.

If your idea came about, children and pensioners would be caught in
gaps smaller than needed to stop bicycle tyres from skimming over.
Perhaps "sensible" in your world means a regular occurrence of hip
and ankle injuries is worthwhile in order to stop one scum cyclist.

Just one?

Try addressing the point about doing more harm to those you want to
protect than usefulness as a deterrent.

Who is frightened to walk across a cattle grid? Not I.

Anyway, the gaps would only need to be about 1.5" wide (and a foot deep).

1.5" won't be enough to catch the tyres of the typical cheap/free/stolen
urban bicycle. (What kind of bicycle do you have in mind?)

Alright... 1.6" gaps. With 12.6" spaces between them. Enough to walk on
safely (texturing the steel surface would help with grip).

When was the last time you heard of anyone being injured walking over
a cattle-grid? No, me neither.

I don't scan the rags for such stories and absence of story does not
mean it doesn't happen. Besides, people walk in all directions on a
pavement but there is no point walking lengthways on a cattle grid. And
I don't expect as many frail pensioners cross cattle grids as those
going to the shops.

Have you never seen a similar arrangement covering the drop to a
basement window (admittedly, usually only attached to older buildings)?

In any case, there are various analogous methods which could be
considered, including making the footway surface too irregular to ride
on, taking a cue from the carriageway "rumble strips" used on the
approach to junctions, etc.