Fragen über die Beispielsätze mit, und die Definition und Benutzung von "Vehicularity"

A: This isn't a word. I hadn't heard of it so I googled it and looked it up in the Cambridge Dictionary and nothing comes up.

"Vehicular" is a word, an adjective meaning relating to a vehicle (a car, van, lorry, etc). For example, "There is no vehicular access to the cabin," means that you cannot access the cabin with a vehicle (you can only walk there, or potentially cycle).