Here's why:
* Practicality: Highways are typically very long, so using smaller units like feet or meters would result in very large numbers, making them cumbersome to work with.
* Common Usage: Miles (or kilometers) are the standard units used for measuring distances on road signs and maps. This makes it easy for drivers to understand the length of a highway and plan their trips.
* Consistency: Using a single unit for highway lengths ensures consistency and avoids confusion.
While other units like yards or feet could technically be used, they are rarely used in practice for measuring highway lengths.
