ah good point, i nvr used that layer before

The customer traffic is already reflected in the land value. So you can simply switch to the Land Value mode for the mini-map and the areas with the darkest colors should have the highest customer traffic.

David, could you ask devs working on the game, if its possible to engineer a layer you can active, on the minimap (although that might be to small), or on the gamemap to see the customer rating.
Ofcourse not per tile, that would make a mess of the map, but per 9 tiles orso (3x3) or 16 (4x4).
Atm when i want to place a new store im swifling all around the cities to see where the highest customer ratings are beside looking where there is room for the building.
Having the option to activate a layer one can easily check on customer ratings throughwhole the city. Not sure if it will ask to much from pc's to have it on the whole map, i imagine it will be difficult to programm to let the layer only be shown in populated areas.

In the picture below is a small example i made in paint (so not much options to make it look nice hahah) so you see what i mean.