Which of the two is correct:
- Tous les petites routes sont jolies
- Toutes les petites routes sont jolies?
Google translate is making sentences out of both.
TL;DR: Toutes is what you are looking for.
As per the TLF
Tout, toute, tous, toutes
I. − Adjectif indéfini
B. − [Marque l'idée de totalité]
1. [Précède un déterm. au pluriel ou bien un pronom]
a) Tous les, toutes les + substantif pluriel
L'ensemble de, la totalité de (personnes ou choses nombrables), sans exception. [TLFi (Tous)]
Here, tout is an adjective, and fortunately it behaves normally: it is variable, so, since les routes is feminine and plural, tout becomes toutes.
As for Google translate: it is a really good piece of software, designed to provide its users with a meaningful translation, even if the input is not grammatically correct, which is great, since most of the actual language is not grammatically correct. As far as I know, it doesn't even know if what you give it is grammatically correct, it just tries to makes some sense of it. So that's no wonder it gives you a translation for both.