I've traveled to Hawaii (specifically the Big Island) several times and drove H19 countless times between Kailua-Kona and Waikoloa. For about 30 minutes you are driving through old lava fields with a view of the ocean, some goats and the other cars on the road. I've never realized the lack of billboards and I thank those responsible for that. I can imagine that drive inundated with billboards if it was allowed. Trying to sell sunset cruises, sunscreen and your next time share.