The state of Hawaii has suggested building a toll road from Kapolei to Honolulu to supplement the city of Honolulu's rail system. Somehow, the thought of paying to run our cars on roads that already exist (like the hov or "zipper" lane) doesn't seem to be a fair use of our roadways and taxpayer money on first glance. A double-decker lane for through traffic into town by the airport and Nimitz Highway is an idea we've heard about before, and will probably hear about again, and it might be the best answer.
Right now, it's all a lot of talk, and one can only hope that concrete decisions, literally "concrete", are formulated and worked out before our grandchildren listen to this same discussion 20-years from now. A thorough survey of what works and doesn't work in other metropolitan areas is certainly a good place to start before funds are allocated and politicians' legacies are drawn up.