superhighway
noun /ˌsuːpəˈhaɪweɪ/
/ˌsuːpərˈhaɪweɪ/
(North American English, old-fashioned)- an interstate (= in the US, a wide road, with at least two lanes in each direction, where traffic can travel fast for long distances across many states. You can only enter and leave the road at special ramps.)