Rear LED light effectiveness.

Discussion in 'UK and Europe' started by [email protected], Mar 14, 2006.

  1. > Without wishing to be hostile, that does what good, precisely? Usenet is
    > a several-tens-of-million node store and forward network, of which
    > Google is just one (albeit significant) node.

    As google keeps the posts forever, it'll remove it from the (only?) eternal
    archive of flamewars and spam.

    > Sorry if that's slightly tetchy. I do get irritated with people thinking
    > that the way /they/ access Usenet is the 'only' way

    Yes, everyone knows there are *two* ways to access this forum: Google
    Groups and Cycling Forums ;-)

  2. John Pitcock

    John Pitcock Guest

    I've just read the discussion on flashing rear lights, here's my comments:

    I agree with those who say that chasing lights are not effective as from a
    distance they look like one LED
    permanently on.

    Some early flashing lights seemed to spend a small fraction of the time on
    (about 0.1 second per second). They gave wonderful battery life but I
    thought they were not good, despite others swearing by them.

    I think the flash frequency needs to be about 0.1 seconds on and off (as
    modern ones seem to). Much faster and it merges into continuous, slower and
    it isn't as eye-catching.

    Lights usually have a wide beam, the LEDs being arranged on a slight ark.
    Because of mounting problems some people put them vertically - lots of light
    up and down but little to the side.

    Some people don't aim the light horizontally straight backwards.

    Rechargeable batteries fade very quickly so a rear light can go out
    unnoticed; disposables give more warning.

    Why do so many cyclists point front lights down to the ground about 2 metres
    ahead? If it's to be seen by then point it forwards, if it's to see by then
    point it far enough ahead to see something before you hit it (and you should
    be looking well ahead not at the puddle of light 2 metres away).
  3. Zog The Undeniable wrote:
    > I thought the drop in output was quite scary when I measured it (I can't
    > remember if the alkalines were new or not - I think they may have been
    > used for half an hour or so). It was a full stop on the light meter at
    > a measured distance from the lamp, so the output was halved. Of course,
    > some LEDs may be better than others at coping with rechargeables - I did
    > the test on the (mediocre) Cateye HL-EL200 front light.

    IMHO the conclusion here is that LED lights should really be properly
    regulated. If the light is inadequate with NiMH batteries it will also
    become inadequate with alkaline batteries long before they're fully

    Unfortunately regulated LEDs are harder to find -- I don't know of any
    regulated rear lights. I think the only reason for this is that it
    allows manufactures to exaggerate power to runtime ratio.

  4. Tom Crispin

    Tom Crispin Guest

    On Thu, 16 Mar 2006 09:44:57 GMT, Mark Thompson
    <[email protected]*_turn_up_the_heat_to_reply*.com> wrote:

    >> It's an open offer. Tell me why you think that road conditions in
    >> China and London are comparable, leaving the personal stuff out, and
    >> we'll take it from there.

    >Is it because, despite the roads in China being more dangerous, the Chinese
    >still trundle about 2 up on a bike and no one bats an eyelid. In the UK
    >with very safe roads, going 2 up on a bike makes Terry have a hernia?

    Very eloquently put. Thanks.

    Don't follow these links if you are of tender disposition.

    Let us have a moment of silence for all Americans who
    are now stuck in traffic on their way to a health club
    to ride a stationary bicycle. -
    Congressman Earl Blumenauer (Oregon)
  5. Ian Smith

    Ian Smith Guest

    On Thu, 16 Mar 2006 09:53:05 +0000, Simon Brooke <[email protected]> wrote:
    > Sorry if that's slightly tetchy. I do get irritated with people thinking
    > that the way /they/ access Usenet is the 'only' way, and that what works
    > on their client should work for everyone else.

    .... and especially when the way they do it is the /wrong/ way.

    regards, Ian SMith
    |\ /| no .sig
    |o o|
    |/ \|
  6. Rod King

    Rod King Guest


    My main point is that you saw the cyclist very well even though he had no

    I know that some people say that if it increases the chance of being seen
    then it may save your life and would definately be worth it.

    I do not subscribe to that. I think that any reduction in risk must be
    weighed up against the other factors. You may say that adding a second light
    has no downside. I would disagree with you. There a re a number of downsides

    1. As cycling becomes more popular then motorists will adjust their speed
    according to the risk they perceive from cyclists. More cyclists without
    lights, or low levels of lighting tend to reduce the speed of motorists,
    therefore compensating for any very slight increase in reaction times.

    2. By lighting up cyclists well we are enabling motorists to mnaintain high
    prevailing speeds of 30mph in our communities which are very fast. Within
    towns and villages 30 mph is unnatural and out of line with most of Europe.
    Highly visible cyclists help justify higher speeds.

    3. In countries where cycling is an accepted way of getting from a to b it
    is done with the minimum of fuss. Multiple lights are "fuss". They shift the
    responsibility for being seen from the driver to the cyclist.

    Whilst I respect your right to put whatever lights on you wish as long as
    they are in accordance with the law, I also think that it is responsible to
    consider the effect that they have on motorists attitude to cyclists in
    general rather than just yourself.

    Equally you may challenge the weighting to attach to the above and that is
    OK, but I do not think they should be dismissed out of hand.

    You may say that all of this is rather academic, but then there is no
    evidence that statistically lighted cyclists fare any better or worse on the
    roads than unlighted cyclists.

    Best regards

    Rod King

    Th. <[email protected]> wrote in message
    news:[email protected]
    > Rod King wrote:
    > > Iain
    > >
    > > Let me get this right.
    > >
    > > From 100m away you saw the light.
    > >
    > > How fast does one have to go in order that 100m visibility of a cyclists
    > > rear light is not sufficient warning. If he had been a pedestrian he

    > > not have had any rear light.
    > >
    > > Far from being useless it seemed to be very effective.
    > >
    > > Were you looking for a higher degree of visibility than was reasonable?
    > >
    > > What would you have done if his light had been brighter?
    > >
    > > Would you have driven any differently?

    > Rod
    > In answer to your questions. The street concerned was a well lit
    > urban street. At the point I overtook it was a 30mph limit although it
    > changed to a 50mph limit a couple of hundred metres later. I wouldn't
    > describe his light as being effective as I saw the cyclist (despite
    > dark non reflective clothing) before I saw the light.
    > I wasn't looking for any degree of visibility. If an unlit
    > pedestrian (a drunk perhaps) had been lying in the road I would have
    > seen him in plenty of time and taken the appropriate action.
    > What I would have done if his light had been brighter is I would
    > have seen him earlier.
    > I woud have driven differently by moving into the outside lane
    > earlier.
    > The vast majority of drivers will see cyclists whether lit or not
    > early enough to miss them. But I believe that being very visible might
    > save my life one night when that 1 in 100,000, or whatever, driver who
    > is drunk, using a mobile, with poor eyesight, or careless sees me a few
    > seconds earlier than he or she otherwise might.
    > With regard to pedestrians being seen there was a pedestrian
    > killed a few years ago 2 miles from where I live. He was walking along
    > an unlit road with no pavement and was killed by a taxi (driver sober)
    > who didn't see him in time. If that ped had been wearing bright
    > clothing he might be alive who knows. The accident as far as I'm
    > concerned was 100% the drivers fault but that doesn't make the ped any
    > less dead.
    > Given that it costs next to nothing (in either cash or hassle) to
    > be well lit I see no argument for not running at least 2 rear lights.
    > But it's a free country and its an individual choice. Long may it
    > remain so.
  7. Jonathanallen

    Jonathanallen New Member

    Dec 29, 2012
    Likes Received:
    There is nothing wrong. Led lights are very effective indeed.
  8. thinkonyourfeet

    thinkonyourfeet New Member

    Feb 20, 2013
    Likes Received:
    You are absolutely right.
    The chasing mode in most LED rear lights is rubbish. I wonder how anyone can have the idea to use it.
    I have tried a lot of LED lights and there are only few which are really bright.
    I mean REALLY bright. And bright is right!
    Of course, the battery life of the bright ones is limited, but most of them are rechargeable. So, no problem...