Rowan

I think much depends on the type of wheels and the length of the board... just as various wheel and frame parameters apply to biking.

I have a fair degree of respect for people who use skateboards as transport. The quiet wheels theese days enable them to travel almost in stealth mode. The boards can be picked up and taken aboard buses without challenge. Maintenance is pretty cheap, and parts are available in just about every sports store I have been into.

They also can go where bikes cannot... although there are laws for what are called "small wheel devices" controlling their access to certain areas and on the road. Lighting can use of dark clothing can be issues, however.

I agree with Dahon.Steve... being car free is not dependent on bicycling riding. Walking, skateboarding, in-line skating, and scooters certainly seem to be viable options used by many people.