Originally Posted by
cyccommute
10 seconds!!!??? At a leisurely 12 mph (20 kph) you are covering 18 ft/sec (5 meters/sec). In 10 seconds, you'll have covered 180 feet (50 meters). If a car is coming at me at 30 mph (50 kph), they are covering that 44 feet/sec (13 m/s). My lights are aimed about one car length or about 18 feet in front of my bike. A car coming at me is going to cover that gap in less than a second. Hardly enough time to be blinded and certainly not enough time to need a 10 second diversion of the light.
Nope, not so in my case. Okay, I got how you use your light. You point it down at a rather close distance, while i tend to set the beam center next to parallel to the ground, to cover larger area and to take the advantage of the simple round reflector. So it will be seen very well from 500 meters or more thus the 10+ seconds and that's why i cover it when others appear in front. In cities i just keep it off.
A helmet light is as appropriate for commuting as it is for mountain biking for the very same reasons. It provides a source of illumination that can be directed to where you need the light to shine. If necessary, it can be used to alert a motorist to your presence if they do not see you. I do not shine my helmet light at motorist indiscriminately but there have been times when it was necessary to avoid a collision.
Hm, when mountain biking you are not setting the light at the same angle, are you? If you point the light downwards the illuminated patch will be quite small, not something i would want when riding in the woods.
I didn't say 'most people'. I said "where we cyclists ride". Most every cyclist I've seen rides outside of the flow of traffic most of the time. If you are riding to the right of the flow of traffic, your light is pointed down the road in a straight line on the right hand side of the traffic. Motorists coming at you are between 15 feet (4 meters) and 30 feet to your left, assuming an 11 foot lane and a 4 foot shoulder plus the distance the on-coming traffic is from the center line and the position of the driver of the car. Even if you headlight was a 35 degree flood light, the beam spread at 20 feet isn't 15 to 30 feet. There is, simply, no way that your light could be blinding to other traffic. In addition, a wide flood light is a more diffuse beam than a narrow spot so the amount of light you could spill over into on-coming traffic is less because it is more spread out. That's what I mean by an incorrect observation.
If you encounter out of city someone with the type of light i am talking about (with a wide and uniform beam) you'll definitely want him to switch it off or look away. The contrast is way too large to be bearable.
I also compare bicycle lights to car lights because that is the light that you are going to encounter if you are riding a bike on the road at night. Yes, automobile lights are shaped but they are only shaped on flat ground. Once you throw in hills and differing elevations, the light is still going to travel in a straight line. Motorists deal with bright lights all the time. I was trained not to look at the light of on-coming traffic so as not to be blinded. I think most people were taught the same thing.
Well, here in the Northern Germany drivers are very polite and you rarely get unshaped lights shining into your eyes. They expect same from you. Since i ride in the dark about 6-7 hours per week I try to respect the others. Few times my dynamo light was set too high and people did complain by turning the high beam lights on and off. Most of the Magicshine lights have stronger and much wider beam than my dynolight, so i can imagine it's even more uncomfortable to encounter it on the road. Again, if you point it down and close then it is less of a problem, but i find it is too ineffective.
I don't worry about fellow cyclists because they are even further from my lights then a motorist as I don't ride bike paths at night. If someone is being a salmon, I can't do much for them because they are already violating the law as well as common sense.
But are there bike paths? Isn't it violating the traffic rules not to ride there when they exist?
Low intensity 'be seen' lights are a bandaid at best. In a city environment, my lights are competing with thousands of light sources. A weak 'be seen' light can't really be seen against that kind of background illumination. I've found, through years of night time commuting, that if I want to really be seen, I have to compete on the same level as the motorists. And that means throwing lots of lumens.
Okay, you know what you are doing. If it makes your ride safer and you think it doesn't annoy the others then I am happy with that. My strategy for the city riding is to have a strong shaped light mounted low and a complementary "band aid" on top of the helmet. I can tell there is a noticeable difference between riding with the band aid and without one. I find its enough, perhaps it is because i ride like a pussey, but i don't think any light will always save me from a careless teenager, so i ride like they don't see me anyway.