Originally Posted by
ron.jace
When going up their is less and less air which causes the car to loose power. If the car for example was underpowered and/or too heavy I do agree with you that they likely didn't make it all and were a hazard for everyone else. Going down though their really shouldn't be a problem if you put the transition in a low gear. Last time I went their we had some friends who's daughter wasn't feeling well (was sick) so they rushed back down to the visitor center. They only used their breaks and they were fine as well.
This is the road for anyone interested:
http://maps.google.ca/maps?hl=en&q=b...,84.9,,0,15.36
The lower air density is exactly what makes the road so dangerous on the descent - less air to cool the brakes results in quick overheating. On most cars, 2nd gear is not low enough to control speed and 1st is too low and can result in engine or transmission overheat or failure.
Just because some people have made it up to and down from the summit without incident doesn't make it a sound practice. I've been to Mauna Kea many times and we have at least one forum member who works there - there is no way I would recommend or endorse the use of a regular car (especially one you don't own) on the summit access road.
There is nothing wrong with reserving a 4WD at the Hilton, parking your regular rental in their lot (which is free until they fix the gate), taking their 4WD up, then returning it after the evening tour. You can leave the keys with the Hilton valet, grab the regular rental car and drive back to the hotel/condo from there - even easier to do if one is staying at/near the Hilton. With a little planning and a National code from our very own National forum, this can be done quite inexpensively and at a fraction of the cost of Harper's.