Imagine the conversation going on...
The strangest thing though was I found myself in Hilo, and got a text to meet on the other side for a catamaran cruise. I looked at the map, and took the only road that traversed the 'gut' of the island, Saddle Road, and made it to Kona in a short time. A local asked me how I got there so quick. 'Weren't you in Hilo? We thought we might have to wait for you'. I took the only road I could find, and got here in plenty of time. 'Which road? Did it have gravel areas?' Yes. The look was of shock verging on horror. Saddle Road claims quite a few visitors in rental cars every year apparently, and a couple had just died on it a few weeks prior. But I had a BLAST! I caught air in the rental car but never 'pushed it'. I've ridden enough dirt bikes and bicycles to know that you NEVER trust what you can't see. There were quite a few parts of the road where I couldn't see what was ahead, and knowing that it likely meant a turn, I would slow down quite a bit. One in particular, I remember, had a bump with a lip and just past that, a hard left. Yeah, I can see that one claiming a lot of stupids for sure. If you hit it too hard, that lip could toss you in the air, and you miss the turn and there was a drainage ditch with a steep-ish bank staring right at you. Gravity is a bitch, and inertia is its wicked sister. Auguring a rental car into that bank is not going to go well.
I was told to under no uncertain terms admit that the car was on Saddle Road, and to look at the agreement to see that it is specifically excluded from all protection and insurance plans offered by the rental agency (it was) but it's the most fun I've had on four wheels. You can be fast and not reckless, but I can see where that would be a 'killer ride', too literally. (I'm sure with today's GPS equipped rental vehicles, they would know you were on Saddle Road before you did, taking all of the fun out of that island)
Saddle Road used to be for military tanks and heavy weaponry. It was in surprisingly good condition for that purpose. My experience with 'military purpose roads' is 'make them as rough as possible!'...
Avoid Saddle Road, and also gravity and her evil sister too.
EDIT: Colorado: I found a park sign when out driving around and though 'What the heck, I have nothing else to do, why not.' It was the sign for Mount Evan. The highest continuously open road on the northern hemisphere! I started getting altitude sickness about half way up. By the time I got to the top, I was gasping for breath, and quite dizzy. I was mesmerized by the storm clouds in the west, and how they were encompassing the mountain tops and the licks of lightening flashing out. I also remember seeing mountain goats. The ride down was filled with horrific images of me in my car going down off the shoulder. It looked like some areas went all day, down down down... Too funny. When I was in far better shape, I went to Denver and had no ill effects from the altitude. Amazing what being athletically fit can do for you. I didn't do Mt Evans, but I was having a hard time even just walking aroud Denver, and the last time, I rented a road bike and rode for three hours up and down the river park trails. (I got lost too)