If you were ready to change lanes, it means that no cars were in the left lane next to you, right? If so, the rider either had to move into the gap opened next to you (and therefore you'll see him there and stay put), or be prepared that you can move over, and therefore not passing you until situation resolves.I visited CA back in December due a SQL Cluster Project I had.
I was driving the rent car, going early to my office there, and barely saw someone (a rider of course) sharing the lane with me. I swear God I was not going to block him or something, but because traffic jam in front of me, seconds before I thought in changing lane and move left.