Russian oil is quite a ways West, around Kazakhstan, and China's population density is to the East. The trip would be around 5000km, and take a week on good roads. Perhaps double or triple this depending on the season, and maybe with a "Russia" multiplier.

So multiply that 43,000 by 14 to 42, or more, and you're within a factor of ten of all (~16M according to Google) commercial trucks in the world, of which only some fraction are tanker trucks.