Vehicle where one after mass transported by people in a ferment (10)

'vehicle' is the definition.
I know nothing about this answer so I cannot judge whether this works.

'one after mass transported by people in a ferment' is the wordplay.
'one' becomes 'I' (Roman numeral).
'after' is a charade indicator (letters next to each other).
'mass' becomes 'mob' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'transported by' means one lot of letters goes inside another (some letters carried or transported by others).
'in a ferment' indicates an anagram.
'i' after 'mob' is 'mobi'.
'people' anagrammed gives 'popele'.
'mobi' placed within 'popele' is 'POPEMOBILE'.

'where' is the link.

Can you help me to learn more?