I think a better solution would be a user setting for whether or not you're interested in conversation during the ride. If you are interested in conversation,

I think a better solution would be a user setting for whether or not you're interested in conversation during the ride. If you are interested in conversation, I don't think solicitation is that inappropriate, as long as it stops at the first moment you say you're not interested. Like you say, it's common for small business owners to be driving to supplement their income, because driving doesn't pay a living wage by itself. I don't think they should have to hide that fact from you.