It is very interesting that COE system, once a friend had told me something about the auction of permits to drive cars in Hong Kong and I imagine that they will be similar to some extent.
Regarding the use of its values to build an indirect indicator of the economy, to detect the beginning of periods of inflation, because I also find it interesting and it would be good to test it with a greater amount of data to confirm the degree of utility that can have .
Thanks for sharing this idea.
I think in HK, they control the number of cars by restricting the number of parking lots. It is not cheap to get a parking lot in HK since land is so expensive.