The government has begun its experiment with toll-free expressways. As nearly as I can determine from the maps they've been showing on TV, 50 rather small sections scattered throughout the country have been declared toll-free and are being observed for changes in traffic flow on them and on nearby ordinary roads.
The total length of the sections is said to be about 20% of the total expressway length nation-wide. Although there are some areas of Japan in which I haven't driven--basically southern Kyushu, northern Hokkaido, and all of Shikoku--I'm still pretty sure that the segments they chose for the experiment are among the most remote and least-traveled. It seems to me that the only thing making them even marginally useful as a test of going toll-free on the whole expressway system is that they do seem to be pretty much evenly scattered geographically.
Unfortunately for any validity to the experiment, the population of Japan is not even close to being distributed geographically. In fact, without having checked but based on pretty fair empirical knowledge, the 50 sections seem largely to avoid areas of dense population (and, of course, heavy traffic).
Early reports showed an average of 163% usage of the now-free expressway sections, compared with the same time last year, and as much as 270% in one area of Yamagata. I suspect that the beginning of Yamagata's lucrative cherry season may have a lot to do with that figure, as truckers take advantage of reduced costs.
Predictably, nearby railway operators are unhappy, and have responded by offering discounts--some in combination with local taxi companies--to encourage people to ride trains instead of driving on the newly-free expressways. Truckers interviewed on TV were also predictable in being happy about reduced costs but concerned about the likelihood of increased congestion and traffic jams.
It looks to me as if some of the roads, both national and prefectural, near the test expressway sections will naturally become less congested as many drivers opt to use the expressways instead. Other than that, I see little real benefit for most of the areas chosen on the experiment, since it's virtually impossible to see how any real impact on tourism can be expected from such localized piecemeal changes. From the Tokyo area, I believe it would cost me several thousand yen to drive to even the closest of the free sections, for example.
I also fail to see how the choice of areas can possibly be of any real use in determining the results of making the whole expressway system toll-free.