[dasil003]

Which I have to say sucks for the rider behind you. If you demand that level of visibility get a high vis vest. Personally I err on the side of assuming every car will try to kill me. It's kept me alive in SF, London, and worse places where most people are scared to bike on roads for good reason (New Mexico).

[photojosh]

For maximum visibility safety when riding alone, I turn on the maximum-output, blinking mode (which IIRC is actually illegal in some other countries). But when group riding, dim it down and turn it on to the solid-on mode.