Similar to your idea, if the laser wasn't rotationally stabilized, the image on the ground would jitter around as slight angular tilts of the bike frame would be exaggerated the further the distance the image was projected. Imagine standing to pedal hard up a hill - the lanes would swing wildly left and right.

How about a lighted fog beneath the bike (like those under some hotted up street cars), giving it the same visual footprint, and territory, as a car?

Or even just a spoke POV system[1], so there is quite a bit more light visible from the sides?

[1]: http://www.ladyada.net/make/spokepov/

hey, that's really cool. I like your point that it's lateral visibility that matters. But I think in practice, the side of the bike is visible only for a very short time (as a car passes it), and the driver is looking forwards (not to the side). The bike needs to be visible from behind.

Another projection idea is a downward-facing rear light - perhaps angled so that the light reflected from the road hits the eyes of the drivers behind?

I've biked as primary transportation for five years (including through Michigan winters), and in my experience ensuring that other drivers see you at intersections is most important. They're often unclear about intent, who has right of way, etc., when they see you at all, and that's where paths cross.

Being visible from behind is also important, but doesn't take anything extravagant: A five-red-LED blinker on your bike and a blinker on your helmet or large reflective strips on your bag is almost certainly sufficient. As long as you're not weaving from lane to lane and not terribly unlucky (e.g. being followed by a drunk or a car full of reckless teenagers), it's unlikely you'll get hit from behind.

(Fog/glow under the bike would be awesome, though.)

OK, your empiricism beats my theorism.

Thinking of my own experience (I've ridden daily for a couple of years), the only two close-calls I've had are from a car that's in front of me, when it suddenly sees a parking spot, and swerves across, almost side-swiping me.

I could probably avoid this by riding in a full car lane, instead of to the left of it (between the lane and parking spaces), but it seems wasteful to take up a whole car lane (and I can't pass cars then). Also, what I'm doing may be illegal, as it's not marked as a bike lane.

(Bonus: fog/glow is more visible when raining.)

1. I don't know why I didn't check Instructables sooner. :) http://www.instructables.com/id/DIY-Glow:-Ground-Effects-Lig...

2. Barring unusual state laws, taking the lane is usually legal. IIRC, in Michigan the law says something handwavey about riding as far to the right as is safe and practical. I will generally take the lane (right lane if there's two, or a wide shoulder), but try to be cognizant of traffic buildup behind me. Riding in a manner that seems predictable to drivers contributes more to safety than following the law to the letter, anyway. Route choice probably also makes a big difference.

1. That glow ground effect is pretty much what I was thinking, except, for the glow source to not be visible itself - you just see a mysterious glow from under the bike.

Easy enough to shade the sides (perhaps with a reflective surface, so as to not waste the light). Of course, being more visible makes it better - just doesn't look as cool (IMO).

But also, it doesn't give a sense of the space around the bike. That was the main idea I got from the original article, of a projected "lane" - it's not to make the bike more visible, but to display a cushion of space around it (a territory), so cars don't drive too close.

2. I meant it was illegal what I do (which is to ride between the parked cars and single lane of the road. Also a danger of a parked car's doors opening). I agree with your other points (esp route taken!)

1. That glow ground effect is pretty much what I was thinking, except, for the glow source to not be visible itself - you just see a mysterious glow from under the bike.

Easy enough to shade the sides (perhaps with a reflective surface, so as to not waste the light). Of course, being more visible makes it better - just doesn't look as cool (IMO).

But also, it doesn't give a sense of the space around the bike. That was the main idea I got from the original article, of a projected "lane" - it's not to make the bike more visible, but to display a cushion of space around it (a territory), so cars don't drive too close.

2. I meant it was illegal what I do (which is to ride between the parked cars and single lane of the road. Also a danger of a parked car's doors opening. I agree with your other points (esp route taken!)

One thing that's unclear about that article is whether the reported conclusions are the result of a rigorous study, or just the anecdotal conclusions of an individual professor.

Also, the idea that a biker with a helmet is more experienced than one without a helmet seems strange: in my experience, a lot of the most experienced bike riders don't wear helmets. I don't think there's a widespread stereotype about it, anyway.

But so do many of the people who are essentially homeless and just riding a broken Huffy against traffic.

(Also, the article is from the UK. Cycling there is probably sufficiently different from in the US (due to city layouts, cultural acceptance of cycling, etc.) that there may be too many other variables to compare them.)

Speaking as someone who lost a close family friend to an accident where a helmet would've saved him... I still think I would wear the helmet.

Even if you do get injured, I'd think it would be far less likely to be the kind that puts you into a vegetative state.

Sorry to hear about your friend.

I've personally decided that my skull and its contents are worth protecting, and worth protecting well, and feel naked riding without a good and properly-fitted helmet.

That's an interesting article. However, I suspect the additional protection provided by wearing a helmet more than makes up for the slight increase chance of being hit by a car. Especially when considering being hit by a car isn't the only way to crash.

I've also seen the argument advanced that requiring helmets makes cycling less safe: Some people will refuse to wear them and won't bike at all, and others will get the impression that cycling is more dangerous than it is because a helmet is being required. (Are drivers or pedestrians nagged to wear helmets? Besides, the most common injury from cycling isn't a head injury - it's a broken wrist from trying to stop a fall.)

The decrease in cyclists on the road reduces the likelihood that drivers know how to share the road with them, that cyclists will learn from each other how to ride safely in traffic, etc.

Even more important in Amsterdam: Pretty much every one driving car also rides a bicycle from time to time. So cars almost always have a sympathetic attitude towards cyclists.

Except cabbies, it seems. :/

It's the tram drivers that really take no prisoners :-)