My grandparents will drive only on roads recommended in printed travel guides; they'll ask the rental car company if Waipio Valley Road and the road to the top of Mauna Kea are sanctioned.
A rented 4WD vehicle is allowed by law to travel ANY public roadway in Hawaii. AND there are some places that require a 4WD vehicle.
If you travel down into Waipio Valley or to the top of Mauna Kea, you are legally allowed to do so, but your rental company will expect you to pay for any damage incurred whether you selected the insurance or not, as the insurance is null and void when you violate the contract.
I do not believe a 4x4 rental is necessary for 99% of visitors. For the other 1%, "necessary" is too strong a word!
But, being in that "1%" category, there ARE worthy places to go on the BI that require 4x4 (the kind you can rent from a normal rental outlet, not the kind locals may drive). I won't publicize those places because I don't want such places to become overused. [I bolded.] Just don't believe it when you read here that there is absolutely no place at all worth visiting that would require 4x4.
- I doubt the Tripadvisor comments overhead, as none of them discussed potholes:
- Please see the bolded phrase. Where on the BI requires an SUV?