The speed limit is irrelevant. What's the community accepted reasonable speed? I would wager that it's not much different than the same highway conditions elsewhere.

people drive the speed limit here. its a much different driving culture than the mainland and it helps that speeding is aggressively ticketed.

There's also the fact that there are only 4 Interstate highways in Hawaii totaling 54.9 miles, while in California, there are 25 Interstates totaling 2,455.7 miles. So, we've got more space to get up to speed ;) and, of course, longer distances to travel...