rvRider mentioned "target fixation". That's what comes to my mind when I visualize a car somehow coming into my path -- I'm working to AVOID target fixation.
Someone else mentioned watching driver's heads, hand, and the car's front wheels. My eyes are in constant scan mode, watching all of these things and, most importantly, looking for openings or escape routes. This is the primary reason why I don't ride with music. I'm way too much of a space case to introduce a distraction like that. I need all of my feeble mental faculties intact so that I can stay aware... At least when I arrive at my destination I'm fully awake and aware.
For those who've never seen or read it, take a look at the Hurt report:
"The Hurt Report"
In particular, points 26, 28, and 29.
No, I'm not saying this report is some sort of definitive source, but I think it's the best we have.
I race downhill mountain bikes. And have bailed off of my bike at high speeds in very steep, rocky, and tree-lined places. Have yet to sustain any major injuries, but it's never a super-fun or desirable thing to have to do. And I wouldn't equate this with somehow being able to pull off a similar move on the street. Jeez, just thinking about this now gives me the willies.
I had a car pull directly across my path one day as I was less than a block from where I park my bike. I ride with my first two fingers on the front brake at all times and am really glad I had that habit in place. I grabbed a full dose of brake. The forks dove and the wheel pulled hard to the left, perhaps because that's where my "out" was, but just as likely it pulled due to the tire starting to slide and the mass imposing itself. I did not apply any rear brake. I stopped inches from the front fender, close enough for me to just raise my right hand and slam it down on the hood of the car. He backed up, I rode off.
So go ride your bicycle and practice seeing the way out, the escape routes. Be safe, ride another day.