Comments on: Does a Forward-Facing Bike Light Increase Rear Visibility?

By: Coggs Malone

Coggs Malone — Wed, 20 May 2009 22:43:30 +0000

Anon – can I get you to clarify for me, what you mean by your remarks “That’s Australia for you. Wonderful place for a holiday, but there is always a nasty edge waiting under the surface”? Exactly what do you mean. Don’t slag Australians, my inference is that you, for some reason, harbour some sort of bitterness towards being Australian. We do have to have a serious look at our bicycle laws but what country doesn’t?

By: chris hutt

chris hutt — Sat, 25 Apr 2009 20:34:40 +0000

Sorry, slight typo in last para. ‘Front bicycle turned backwards’ should of course be ‘front light turned backwards’.

By: chris hutt

chris hutt — Sat, 25 Apr 2009 20:31:25 +0000

A forward facing bike light could marginally decrease rear visibility when viewed in the headlights of a car since the background against which the cyclists is viewed will be slightly lighter with the addition of the light from the cyclist’s own front light.

The cyclist himself will typically be illuminated by the car headlights to a greater extent than the background against which he is seen (he’s nearer, presents a surface largely at 90 degrees to light direction and typically wears something lighter than the background which in most cases will be tarmac).

So with the addition of the cyclist’s front light there could sometimes be a lesser degree of contrast between the cyclist and the background against which he is viewed, hence reduced rear visibility.

Of course any such effect will be highly marginal compared to other factors, but might nevertheless we worth noting with reference to such perverse arguments as that put forward by the defence in the case cited.

In a similar vein you might be interested to know that I experimented for a while with a front bicycle turned backwards to illuminate me rather than the road ahead. I reasoned that it would be safer if a motorist about to pull out could clearly see a cyclist approaching rather than just a point of light whose distance away can be difficult to judge.

By: Gary K.

Gary K. — Thu, 23 Apr 2009 21:15:14 +0000

Although certainly beyond requirements of law, I do any longer night rides using a niterider minewt X2 headlight with a lithium ion battery pack. That light, without considerable extra weight, really can project at far distances, and the focused beam on flash mode really picks up anything reflective ahead, even blocks ahead. It turns stop signs, parked car license plates and tail reflectors into a disco party effect that makes it unmistakable that I am riding from any direction. I sometimes get people complaining my light is too bright and hurting their eyes, but that to me is a sure sign it is working. I also never ride with less than two rear facing lights.

As for this case though, a front light should be irrelevant to a strike from the rear since 99% of bicycle front lights could not project far enough ahead to be significant enough visibility to be seen from the rear.

By: Darrell Noakes

Darrell Noakes — Thu, 23 Apr 2009 17:23:32 +0000

Just yesterday, I was describing in a conversation how too much cycling “policy” is informed by myth, folklore and superstition, and too little by research and fact. This is a good example of that. Sure, it’s a dumb idea to be out at night without a headlamp, but that had no bearing on this cyclist being struck from behind. A headlamp “visible” from 200m is by no means illuminating the road that far ahead and certainly won’t be visible from behind.(If Australia’s laws read that the beam must “project” that distance, I doubt that they intend to mean that it should illuminate the roadway for that distance, but rather intend it to be visible to drivers approaching from that distance.) Although a tail lamp apparently is required by Australian law, any good rear-facing reflector (e.g. SAE type) is sufficient to alert drivers approaching from behind (the law in this case being yet another example of policy based on superstition rather than fact). The court seems to have made a decision based on misinformed supposition, rather than fact, and cyclists are worse off for it.

By: Anon

Anon — Thu, 23 Apr 2009 16:56:49 +0000

That’s Australia for you. Wonderful place for a holiday, but there is always a nasty edge waiting under the surface. It shows in deliberate assaults on bicyclists also. I’m an Aussie for another year or so. US naturalization papers are in the pipe.

By: Rich Wilson

Rich Wilson — Thu, 23 Apr 2009 15:39:29 +0000

California vehicle code 21201(d)(1) requires a front light visible from 300′ (about 90m). It doesn’t say anything about how far the beam must project.

I’m bothered by the fact that they seem to be judging the cyclist, not the car driver. If one car rear ends another, and the front car has working tail and brake lights, would the front driver’s headlights have anything to do with it?

By: Torrilin

Torrilin — Thu, 23 Apr 2009 15:37:57 +0000

My bike’s front light (a Busch and Mueller generator powered halogen) has a beam that is visible from the front at least 200 meters away. However, it’s a normal headlight, so there is not extensive rearward scatter. My light definitely meets the WI legal requirements for a headlight. When I’m on the bike, it doesn’t seem at all bright, and the beam pattern seems to extend perhaps 30 feet ahead. But to an observer, it’s visible from very far away.

I don’t find it at *all* believable that a headlight makes a difference in visibility from the rear. I have a much easier time following my partner via his tail light. Light is directional, and a light is most useful when aimed at the person you want to see it. The LEDs used in many bike lights are more directional than the halogens used on cars, and it’s easy to see this in comparisons of two lights. (that’s one reason why I’m happy enough to have a halogen front light… the beam pattern is quite broad)

I don’t really think it’s wise to ride without a headlight, but since it was not a head on or side collision, I find the defense argument impossible to believe.