what dynodonn said. I've had too many near misses during the day where cars pull right in front of me. A bright strobe during the day seems to make as much difference as a bright flourescent yellow/green visibility vest. I'll either set the Dinotte or Petzl headlamp on strobe. If it's night time riding and I want a strobe(not all the time) it'll be the headlamp but it's rotated up so it doesn't blind anyone, unless I want it to.