The drive to the Maua Kea Visitor Center is not only worthwhile, it is "other worldly". Be sure to check out the silver sword plants growing around the center!

Also be sure to drive defensively on the Saddle Road, especially at night!

Parts of the road are very narrow with rough pavement edges that tend to cause "center of the road" driving and make head-on collisions a real problem. Dense fog, as moist air rising upslope from the coast meets cold air rolling downslope from Mauna Kea, can make for dangerously low visibility. The road west of mile 35 is also not well reflectorized for night driving. The road had an accident rate 80% higher than the Hawaii average for two lane rural highways, though the recently opened bypass of some of the worst sections hopefully will lower that statistic.

Most rental car companies prohibit taking their vehicles on this road. Also, there are no service stations, so make sure to refuel in Hilo before heading west, or Waimea, Waikoloa, or Kailua-Kona before heading east, especially if you plan to go to the visitor center on Mauna Kea. The high altitude can increase your fuel consumption quite a bit.