The thing with you example is that there is a "time and location bound context" due to which the false positive rate can be _massively_ reduced.

But for nation wide public search the false positive rate is just way to high for it to work well.

Once someone managed to leave a "local/time" context (e.g. known accident at known location and time) without leaving too many traces (in the US easy due to wide use of private cars everyone) the false positive rate makes such systems often practically hardly helpful.