Crows are pretty smart. Obnoxious, but smart.
I love to watch them soar in front of me, too. Yesterday I was descending at about 30 mph and a flock of crows (of course) took off when they saw me. A couple flew the same direction I was going and I was surprised to note that we were traveling at about the same speed. Like pharasz says, once they figured out that they weren't getting away, they changed course. On a few occasions I've had hawks fly right above me for a couple hundred yards. Yeah, I feel kind of like a bird when that happens. Love the freedom.