C
craig
Guest
Im from the uk and now live in australia where i started cycling
helmets are compulsary here whats the story there
is it the law and is it enforced
www.bicyclecommute.wordpress.com
Will Cove wrote:
> Simon Brooke <[email protected]> wrote in news:fru744-dui.ln1
> @gododdin.internal.jasmine.org.uk:
>
> > Even a black cyclist in black clothes on a black bike isn't invisible.
> > If you can't see a black cyclist in black clothes on a black bike in
> > sufficient time to take appropriate avoiding action, then you're
> > driving too fast for the conditions.
>
> We see things by two mechanisms: from the light they generate or reflect,
> and the silhoutte they create against a background of either direct or
> reflected light. Now a completely black object reflects no light, so a
> black object can only be seen via its silhoutte. In the case of a cyclist
> riding in the gutter at night, the cyclist is to the left of the driver
> while the light comes from the headlights of the oncoming vehicles, which
> are to the right. So on a straight road it is impossible for the cyclist
> to be silhoutted by direct illumination. This only leaves the small
> amount of light reflected from the nearside verge (and if the verge
> itself is dark the light it reflects will be next to nothing). However,
> the small amount of light that the verge reflects will be completely
> overcome by the driver's own headlights. Added to that the cyclist's
> wheels hold the bulk of the rider above the kerb line and so the driver
> would see an unbroken kerb line even with the cyclist right in front of
> him. Now throw in the masking effect of oncoming headlights, which affect
> your night vision so that anything below a certain luminosity appears
> black, which means that a stealth cyclist merges completely into the
> background.
>
> Put all that together and you should see that it's entirely possible for
> a stealth cyclist (or pedestrian) to be invisible until just a few feet
> away. Even just ten mph could be too fast to avoid a stealth pedestrian
> and the boys in blue would almost certainly pull you if they caught you
> driving at the sort of speeds necessary to ensure avoidance of stealth
> cyclists and pedestrians.
>
> This isn't about driver competence; it's about physics. It doesn't matter
> who you want to blame, the fact is that if you wear dark clothing, don't
> have suitable lights, and ride or walk at the side of a road at night you
> are taking an unnecessary risk that could be avoided if only you used
> lights and more suitable clothing.
helmets are compulsary here whats the story there
is it the law and is it enforced
www.bicyclecommute.wordpress.com
Will Cove wrote:
> Simon Brooke <[email protected]> wrote in news:fru744-dui.ln1
> @gododdin.internal.jasmine.org.uk:
>
> > Even a black cyclist in black clothes on a black bike isn't invisible.
> > If you can't see a black cyclist in black clothes on a black bike in
> > sufficient time to take appropriate avoiding action, then you're
> > driving too fast for the conditions.
>
> We see things by two mechanisms: from the light they generate or reflect,
> and the silhoutte they create against a background of either direct or
> reflected light. Now a completely black object reflects no light, so a
> black object can only be seen via its silhoutte. In the case of a cyclist
> riding in the gutter at night, the cyclist is to the left of the driver
> while the light comes from the headlights of the oncoming vehicles, which
> are to the right. So on a straight road it is impossible for the cyclist
> to be silhoutted by direct illumination. This only leaves the small
> amount of light reflected from the nearside verge (and if the verge
> itself is dark the light it reflects will be next to nothing). However,
> the small amount of light that the verge reflects will be completely
> overcome by the driver's own headlights. Added to that the cyclist's
> wheels hold the bulk of the rider above the kerb line and so the driver
> would see an unbroken kerb line even with the cyclist right in front of
> him. Now throw in the masking effect of oncoming headlights, which affect
> your night vision so that anything below a certain luminosity appears
> black, which means that a stealth cyclist merges completely into the
> background.
>
> Put all that together and you should see that it's entirely possible for
> a stealth cyclist (or pedestrian) to be invisible until just a few feet
> away. Even just ten mph could be too fast to avoid a stealth pedestrian
> and the boys in blue would almost certainly pull you if they caught you
> driving at the sort of speeds necessary to ensure avoidance of stealth
> cyclists and pedestrians.
>
> This isn't about driver competence; it's about physics. It doesn't matter
> who you want to blame, the fact is that if you wear dark clothing, don't
> have suitable lights, and ride or walk at the side of a road at night you
> are taking an unnecessary risk that could be avoided if only you used
> lights and more suitable clothing.