"The car drives north."
Translation:Tiomáineann an carr ó thuaidh.
This sentence strikes me as rather odd in English. Is it equally odd in Irish? Anyone else feel the same way? The normal usage of "drive" is transitive, in that someone is operating a vehicle. "The car drives" seems to imply one of those new self-driving cars, i.e. "The car drives itself north." I guess you could say "The army drives north," but it would be a bit of a stretch to have that sense apply here.
I think that síos would be wrong in this sentence. On it's own, síos means down, and Tiomáineann an carr síos would just mean "the car drives down". As a modifier with a destination, it can mean "northwards", so síos go Cúige Uladh is "north to Ulster", but it can also just mean "down" - Thiomáineamar síos faoin tuath - "we drove down the country".
There's a bit more about this on the discussion of Táim ag dul suas an bóthar.