The other day I was out riding on a local side street here in Colorado. I looked down for just one second to check my gears. And the next second I was staring at the grill of a Jeep Cherokee coming at me from the left. He was crossing from the oncoming left-turn lanes, but I clearly had the right-of-way. He either did not see me or chose to ignore me as a silly cyclist (as many motorists do). Fortunately, the guy decided to see me at the last second and I was able to swerve around him to the right.
Funny thing is, I had seen the Jeep before and knew he was there in the turn lane. But it was that second of inattention that almost led to disaster.
Situational awareness is one of the key elements in staying safe on your bike. Let your attention stray for just a second and an obstacle can come out of nowhere to wipe you out. This is especially true when you are riding on roads and streets. Staying aware of your surroundings can help you avoid, among other things, the dreaded attack of the left turn.