Translation guide
A roof rack is a set of bars or a frame attached to the roof of a car for carrying luggage, sports equipment, or other large items.
ルーフラック
roof rack
The learner wants to refer to a roof rack in general, such as when asking if a car has one or when buying one.
The most common and direct loanword from English. Widely understood.
この車にはルーフラックが付いていますか？
Does this car come with a roof rack?
Also a common loanword, often used interchangeably with ルーフラック. May imply a more enclosed carrier.
ルーフキャリアを取り付けたいんですけど。
I'd like to install a roof rack.
A literal descriptive phrase meaning 'luggage platform on the roof'. Understandable but not a standard term.
あの車は屋根の上の荷台にたくさん荷物を積んでいる。
That car has a lot of luggage on the roof rack.