I cycle into the city 4 days out of 5 - early in the morning but then in peak hour traffic going home. The ones that don't seem to want to share the space with bikes (from my experience over the last 10 years of work commuting) are the buses - my god, how close can they get to you!
The other thing that is necessary to get people onto their bikes is a supportive employer - we have showers, towels, and a lock up cage for bikes - makes it a no brainer!