I've already been riding in the dark for quite some time, and daylight savings is going to simply put me in the dark both directions.
So far, my greatest hazards, again, so far, have been runners and cyclists.
Runners in the bike lane wearing no reflective gear or lighting at all scare the crap outta me. Even in DENSE fog yesterday, this idiot is out running on the road with no lighting at all. Sheesh.
Next, I am almost wiped out by a cyclist - no lights, dressed in black, and flying down the path. I have two flashing lights (it is starting to get a bit light at that point, so on flash mode) going, this guy, nothing. Barely missed either a head-on or him going way into the puckerbrush - I jumped the curb to the street to get out of the way.
What are your biggest hazards?