On the contrary, cars are the vastly more alienating vehicle. You're in a sound dampened box closed off from every single human being around you. You can't even quickly pull over to chat if you spot a neighbor because the thing is way too big for that.

When I see neighbors driving a car, the most interaction I get is a wave - if they see me at all. However if I'm biking or walking, I will absolutely stop and chat because it's completely natural and human to do that.