I see a LOT of cyclists at night (and day) around greater Seattle. I am interested in lighting visibility and safety because I help outfit a lot of riders for their nightime lighting needs, so take a look at riders systems while i pass.

For urban riding, a flashing LED headlight aimed correctly is very noticeable.

For those on extreme budgets, the very inexpensive, lower powered ones that run on CR3032s have extreme fade - from a oncoming traffic perspective- in front of the rider but are quite bright up close. The new Blackburn Flea?- a rechargeable 3032 system, is 65 lumens in this size but its recharger design might need some rework to make it more user friendly and robust.

Some of the new gen, inexpensive multiple LED, disposable battery headlights are even bright enough to add to conspicuity during the day. Notable the Cateye EL135 for compact light good for day/night safety visibility.

Higher powered, single bulb LED lights with 1W of power like the Planet Bike Blaze or the Niterider Ultrafazer MAX throw about 40 lumens of tight light in front of the rider. These may be bright enough for some to be acceptable for their nighttime 'see the road' needs but are just on the marginal side of useable light to ride by. They are exponentially better than the first halogen bike headlights and world apart from the mini maglight and duct tape fixes of the pre battery headlight era.

For dedicated commuters, highpowered, rechargeable LED systems really represent the best headlight systems available- I'd steer anyone interested in a rechargeable system to avoid the bottom tier of Niterider and Light in Motion as their entry level lights do not have the flash option.

Flashing LEDS may help reduce right of way conflicts during daytime use; riders here in the Northwest are reporting this anecdotally enough to me that I've noted a trend. Other riders have as well, and opinions for daytime lights written about by local bike advocates. You can see, and it's OBVIOUS, a flashing Niterider Trinewt from over a mile out during the daytime. The real value from LED daytime arrays comes much closer in than that, during intersection negotiations and enhancing your visibility to oncoming and potentially turning traffic.

Do not depend on lights to clear a traffic ambiguity but running a bright, daytime visible LED array appears to offer tangible safety benefits.

Anyone riding the winter months in North America should consider a daytime visible LED. One thing to keep in mind- nature doesn't always present either pitchblack or perfect daytime riding. Theres' a lot of gray and limited visibility conditions, shadows longer, the sun lower in the sky.

(and anyone obsessed about side visibility should consider some of the Knog lights- you can wrap them around your fork blades, aim them at any angle forward or square off to the sides and add active side visibility rather easily. I find passive side fleccos satisfactory)