4WD cars for Mauna Kea

[Durian Fiend]

Don't go at the last minute before sunset, you'll be staring directly into the sun on every other switchback.

Oh, that's a good tip.  

During my first visit to the Big Island I had a rent a jeep and drove it to the summit. This was in the early 90's, when Jeeps had relatively crappy brakes. There was no one stopping motorists to check on their cars or physical status.  I don't recall any problems with the Jeep in either direction.

AWD vehicles should be allowed now, no good reason not to take one. 

If a lifted Jeep isn't appealing, maybe rent from a private party advertising on FB or Craigslist.