。
The roads in Hokkaido are wide.
Literal
Hokkaido [of-の] roads [topic-は] width [subject-が] wide.
The construction [topic]は[quality]が[adjective] is the classic 'double-subject' pattern — Hokkaido's roads are the topic, 'width' is the grammatical subject, 'wide' is the predicate. Literally 'as for Hokkaido's roads, [their] width is wide.' A quintessentially Japanese sentence structure.