As has been said, don't assume eye contact means you have been noticed; some drivers are so dense, they could take a 2x4 between the eyes before they notice there's someone in front of them.

A similar event happened to me and my kids today....

On the way to the post office, we were rolling down a side street, when I saw a car easing out of a driveway. The driver stopped as we approached (about 80 feet away), then pulled SLOWLY out in front of us as we got nearer. Making sure my kids heard me, I loudly said, "Hold up, hold up!" The car stopped, we went by -- I gave the driver 'The Look' -- and we went on. I was waiting for the car to go by, but it was three blocks later before it did. (I will give them props for that, but....)

Mine came from the prevailing attitude I've noticed in my hometown, that the overwhelming majority of the Af-Am community gives NO respect to cyclists in the street, and themselves either salmon or ride the sidewalk.