Open Taxi
Empty Parking Space
noun
When a car has sky in it (and not, say, a bunch of people) it is free to give you a ride. If you see this sign lit up on a taxi feel free to hail it down, it will be able to take you somewhere. It is an open taxi.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
あのコインパーキング、空車あるかな？
I wonder if that paid parking has an available spot.
今日はUberもLyftも中々空車がいない。
There are no available Ubers or Lyfts today.
ニューヨークでは、空車のタクシーを見たら手を上げて大声で「タクシー！」と言って下さい。
In New York, if you see an available taxi raise your hand and shout, "Taxi!"