There is a fascinating thread on Mauna Kea in rec.backcoutry about access. You can read the whole thread at:
I will try to excerpt some of the more interesting post here.
This post has 2 notable items: an age restriction of 16 to summit the peak (I don't know if this is enforceable but it might be given the peak's new check in requirements). The restriction is because 100% of those younger than 16 get altitude sickness on the peak (that could be a thread in itself).
The second less interesting aspect is the claim that a lake on Mauna Kea is the highest in the U.S.
Here's the post:
Fred E. Nakaguma [email protected]
Mauna Kea is 13,796 feet in altitude. To get there you take highway 20 from Hilo, more commonly known as the Saddle Road. I don't know what the driving distance is, but most car rental agencies do not allow their cars to be driven on this road. The road is not bad, but there are many curves and bends in the road. The military have a training area up there called Pohakuloa, and I guess there have been a few accidents involving tourists. The only rental agency that allows their cars to be driven up there is Harpers (4 wheel drive vehicles only).
The turn off from Saddle Road to Mauna Kea is at almost the 7000 ft level. You turn right off Saddle Road to go to Mauna Kea. This turn off is a short distance after the turn off to Mauna Loa (left). You are in the middle of cattle country in this area. The paved road continues to about the 9000 ft level. This is where the living quarters for the astronomers is located, as well as a vistor center and observatory for visitors.
The road from there is a dirt road to the top. It is that way to discourage people from going to the top. Too many visitors could result in degrading the seeing up at the summit. You'er supposed to get permission from an office in Hilo before going to the summit. Most of my trips there have been with students and my trips were coordinated through the Institute for Astronomy in Honolulu. I did go there once on my own without any prior approval. I will be taking students up there again during the spring break, in March, 2000.
People under the age of 16 are not permitted at the summit. The reason is because 100% of those under 16 get altitude sickness. On one of my trips up there with 16 students and 5 adults, all but 2 students and 2 adults got sick. Being older than 16 does not insure that you won't get sick.
Near the summit, there is a trail that takes you to Lake Waiau and the adze quarry. You can't move fast up there because of the altitude. The summit is where the astronomical observatories are located. The roads up there are paved to keep the dust down. The road up is the only way I know to get there.
Fred E. Nakaguma