You might emphasize the parking thing. I always have a place to park my bike that is closer than the handicapped slots for cars.
Depending on the group, you could mention that it is smarter and more scenic to ride a block or two over from the main arterials. I've discovered some pretty neat houses, gardens and views on my bike that would have gone unseen and unappreciated in a car.
I'd also not make too much of the health and environmental aspects. It's too easy to get preachy and turn people off that way. Though, fitting into sexy clothes more easily is always a selling point...
Give big space to the festive dog that make sport in the roadway. Avoid entanglement with your wheel spoke.
(Sign in Japan)
1978 Raleigh Gran Prix
2003 EZ Sport AX