An anecdote that illustrates for me a gap between cars and bikes.

To get onto the bike path that I take on my commute, you have to climb up a steep narrow ramp with two 90 degree right turns. Running parallel to this ramp is a driveway into a parking lot. Last week as I was hammering to get up the ramp, a very very large lady in a stopped car hailed to me from her open passenger window, "Excuse me!" When I didn't stop, she called out even more insistently, "EXCUSE ME!" I tried to yell back, "Hey, I'm riding up a steep hill, I can't stop now," but by then I was past her and I don't believe she heard me. When I reached the summit, I stopped to see if I could help her. Maybe she was lost, I don't know. She started talking to me across her car through the passenger window, but I couldn't hear her. I wasn't gonna ride back down, and it was obvious that she sure wasn't gonna get out of her car to talk to me. I was only 25 feet away, yet we were not communicating at all. After about 10 seconds, I realized the futility and got back on my bike and pedaled to work.

No big conflict, but as I continued my ride I contemplated how this situation seemed to be emblematic of a divergence between cars and bikes.