[alsodumb]

When the total distance traveled for the shortest vs fastest option is very high, Google always shows both the options (or at least, some versions of them).

I think safest route is hard to define, especially given that the data is not dense and may not be relevant (e.g., an intersection had a lot of historical accidents so its technically unsafe based on data but it has been rebuilt recently and there has been no accident since so its currently safe).