when i worked days, i found morning to be more pleasant and easier than afternoons. it seemed the traffic was heavier later in the day. i often took slower alternate routes in the afternoon to avoid traffic, not out of fear, but because it was much nicer to ride where there was shade, fresher air, and quiet streets.
so i guess i see heavy traffic as an obstacle, mostly to my enjoyment. it's about the same when i drive or ride my motorcycle.
now that i work nights, traffic is not that bad in either direction. i don't miss the busy traffic of rush hour, but i do miss being awake in the daytime.
