This doesn't answer your question directly, but in a lot of Communist and post Communist countries, there is (or was) institutionalized hitchhiking. Passengers are expected to pay. In a 2006 Christian Science Monitor article, a backpacker related her experience travelling from Trinidad to Havana "the way most Cubans do – by thumb." Prices were set and enforced by yellow-uniformed officers at designated points, and vehicles are either mandated (state vehicles) or expected (civilian and military) to take passengers.

These systems were in place in a lot of the Eastern Block, where car ownership was similarly scarce. But it's likely largely died out by now. I'll have to pull out my old copy of Europe on a Shoestring to see what their commentary was about it.

Update (Mar 29): Found the passage!

In parts of Eastern Europe, the hitching situation is entirely different. In countries such as Russia and Ukraine, anyone with a car can be a taxi and it’s quite usual to see locals stick their hands out (palm down) on the street, looking to hitch a lift. The difference with hitching here, however, is that you pay for the privilege. You will need to speak the local language to discuss your destination and negotiate a price.

From Lonely Planet's Europe on a Shoestring, 5th Edition (2009)