What do you look for in a rear light?

1philipm

I'm doing some research into cycling safety and rear cycle lights. Looking at DfT and RoSPA stats, it seems that most accidents happen in daylight, in urban areas and at or near road junctions.

I can't help but think most rear lights are not bright enough in daylight (or have very narrow, rear facing beams). Should bike lights be as bright (or brighter) than car stop lights (which have dozens of LEDs)? Seems sensible, right?

I guess you could make a very bright light, but then then battery would be large and heavy. If a light could use sensors to determine the likely risk to the cyclist and then flash brighter when needed, it could use its power intelligently and be much smaller.

So for me, my ideal light would be at least as bright as a car stop light while still being small, light and convenient.

What do you look for in a rear light? Or what problems does a light need to solve for you?

Thanks,
Philip

hipshot

Doesn't the fact that most accidents happen in daylight suggest that visibility is not the main problem anyway?

I do use a bright flashing rear light in the day - I think it draws the eye and reminds drivers that i'm there. It is cheap lightweight and small. In other words the problem already has a solution. I think a really blinding lazer-bright light might be too annoying.

Sprool

dusk's worst. The contrast between the approaching darkness and the LEd is at lts lowest. This question is a no brainer though - bright, lightweight, inexpensive, rugged, low power consumption, that's it.
Choose any two of the above. As soon as you try for a third feature things start to fall short of the mark.

Mikey41

Something that bright would be too much. Ever sat behind someone at the lights with their foot on the brake? The intensity of the light is almost painful. A bike light could conceivably use a light sensor to turn up the brightness a bit during daylight.

I use twin 5-LED lights at the rear, one steady and one flashing. So far, so good.

Junctions are the most dangerous area, agreed, but many cyclists don't help themselves there by riding in the gutter. This either tempts drivers behind to pass and left-hook them or a car will pull out on them as the driver is looking into the road and not down the gutter.

styxd

red

simon_masterson

Bright, affordable, non-flimsy and with decent battery life (though thankfully we seem largely to have ditched halogen bulbs...) add up to a rear light that is good enough for me. I have a CatEye Rapid 3 which I've been using for about a year and a half now; it ticks all of the above boxes. It really is very bright; I'm sure I could get brighter still, but nevertheless I'm not at all concerned. One of the best £20 investments I've ever made.

jthef

I think this problem will get a lot worse with more cars having these new bright HID day light bulbs. They are just too bright and distracting. It will be too easy not to see a cyclist when there are any of these anywhere near, as your eye is drawn to them too much and away from what you may need to see, a nearer car, cyclist or pedestrian etc.
I have very bright lights which are good in daylight to be seen and some would say maybe too bright at night.
My rear light is this http://www.ebay.co.uk/itm/Magicshine-MJ-818-Cycle-rear-Bike-light-Y-splitter-cable-for-MJ-880-880U-880E-/221191568338?pt=UK_SportsLeisure_Cycling_Bike_Lights&hash=item33800b7bd2 .
and last very well but big battery but it is shared with my front light.
This time of year I use lights in the day light a fair bit but not in summer.

1philipm

hipshot wrote:

Doesn't the fact that most accidents happen in daylight suggest that visibility is not the main problem anyway?

Yes, I've given that lots of thought too, especially with all the high-vis available. If you've ever followed a car without working brake lights, you probably almost ran into the back of it. Does it seem reasonable to expect a driver not to drive into anything that has a nice bright red light on it? That's my working theory.

Sprool wrote:

dusk's worst. The contrast between the approaching darkness and the LEd is at lts lowest.

Interesting. I was assuming that it was all about brightness (not contrast). On reflection, you're right of course! I must do some spot meter readings with a digital SLR to get an idea of how the brightness's compare (day sky, day ground, car stop light at various distances, typical bike light at various distances).

Pickled Pig

Change out of a fiver.

Graydawg

styxd wrote:

red

Dammit you beat me to it!

iPete

Bright but not blinding, a good even spread of light at night across the road but visibile in the day. An uber mode for foggy or heavy rain days.
Build quality, must be bombproof for all weather.
A battery that can be shared with a front light, re-charging AA batteries gets tedious during a long week.
A solid mount.

The Hope District basically. Genuinelly get more room since adding this.
http://www.cyclistno1.co.uk/gear/access ... rict-3.htm

keef66

1philipm wrote:

hipshot wrote:

Doesn't the fact that most accidents happen in daylight suggest that visibility is not the main problem anyway?

Yes, I've given that lots of thought too, especially with all the high-vis available. If you've ever followed a car without working brake lights, you probably almost ran into the back of it. Does it seem reasonable to expect a driver not to drive into anything that has a nice bright red light on it? That's my working theory.

You seem to be assuming all the accidents at junctions involve a cyclist being hit from behind because another road user hasn't seen them! I suspect most are caused by motorists turning across a cyclist's path because they failed to spot them or failed to appreciate how fast they were going. I include in that the classic left hook in which white van man overtakes a cyclist then immediately assumes it's safe to turn left.

You could have a magnesium flare sticking out of your @rse, and still be at risk from driving like this.

1philipm

keef66 wrote:

You seem to be assuming all the accidents at junctions involve a cyclist being hit from behind because another road user hasn't seen them! I suspect most are caused by motorists turning across a cyclist's path because they failed to spot them or failed to appreciate how fast they were going. I include in that the classic left hook in which white van man overtakes a cyclist then immediately assumes it's safe to turn left.

Thanks, very true. There are plenty of really bright front lights out there, but there seem to be few really bright rears.

Sounds like I should add "good side visibility" explicitly to my list of needs.

racingcondor

I suspect that the statistic that 'most accidents happen during the day' is also severely distorted by the miles ridden during the day compared to night.

What do I look for - Bright enough to be visible, doesn't fail in the wet.

What bugs me at the moment - The drive for ever more visible lights has led to so many rear lights that have really fast strobe modes which are completely dazzling (Cat Eye Rapid 3 anyone). A driver who can't see anything apart from your back light isn't a safe driver.

slowbike

racingcondor wrote:

What bugs me at the moment - The drive for ever more visible lights has led to so many rear lights that have really fast strobe modes which are completely dazzling (Cat Eye Rapid 3 anyone). A driver who can't see anything apart from your back light isn't a safe driver.

Hmm - I have the Cateye Rapid 3 - IMHO an excellent light for night time/poor vis commutes - which takes me down a main road.

It's only dazzling if pointed directly at you and you're in close range - if a driver is that close then they're too blummin close!
I run it in conjunction with another rear light. I'm pleased with it !

Might try and do some vid of it for demonstration.

Pross

I'd like one that which has a two tone brightness if that makes sense so that it is flashing but never off. Brightness-wise I'd say the lower level needs to be brighter than a car tail light (due to having a smaller area) but that it will pulse to something brighter than a car brake light. It needs to be reasonably small but still have sufficient surface area to be easily seen, preferably be re-chargeable via USB and with at least 12 hour life from each charge and maybe with a daylight and night time mode with the daylight being marginally brighter to show up in bright light conditions whilst the night mode doesn't damage the retinas of drivers following you at night. The strobe / flash mode is better being a fairly slow rate to prevent the problems mentioned above.

Gpfanuk

A bulb. :P

Bustacapp

A red light.

How much time have you dedicated to thinking about this?

team47b

Pickled Pig wrote:

Change out of a fiver.

Top answer!

ToeKnee

team47b wrote:

Pickled Pig wrote:

Change out of a fiver.

Top answer!

Depends on how often, and for how long, you are going to be using it! You need to factor running cost, and the life of the light, to project a true cost of ownership. Hence, I buy reliable rechargeable lights.

Anonymous

The £2.50 phart beep is pretty good. No change from a 5er including postage, from P-X.

Was out meeting my brother in a thick low lying fog in the new forest and you could see him a mile off. I was actually pretty surprised.

Akirasho

... as mentioned as bright as possible and luckily, new LEDs have made that reasonably attainable... now we add things like multiple flash modes and such, but for me the thing would be portabilty 'tween bikes... (last year I found a blinky that fell off someone's bike during a tour cuz the band that held it on failed... light still works great (DIY'd another mount))...