Waipio Valley Road in HI is the steepest road in the USA

Waipio Valley Road is a short steep road located in the Hamakua District of the Big Island of Hawai’i, in USA, restricted to 4x4's. It is the steepest road of its length in the United States. The road is steep enough to destroy brakes on the way down, with some 45% grade sections.

Can you drive into Waipio Valley?

The road is 2.25km (1.4 miles) long. It links Waipio Overlook at the western end of Honokaa-Waipio Road (State Route 240), down into the Waipio Valley, in the Hamakua District. Once on the valley floor, there are no paved roads. In the Hawaiian language "Waipiʻo" means curved water. The Waipio Valley Road looks like a real road, not a street, and offers such a great experience for cyclists. As a courtesy, at the very few wider locations in this extremely narrow road, downhill traffic yields to uphill traffic. Sometimes it is not recognized as a road because it is open only to 4-wheel drive vehicles, but it is a good paved road well maintained by the government.

Is Waipio Valley the steepest road?

Tucked away on the northeast coast of Hawaii's Big Island, the road is extremely steep, running from 279m to 7m above the sea level. While the road is now paved, it is steep enough to destroy brakes on the way down, and stall engines on the way up. Folks going down have to yield to folks coming up. Only cars with very tough four wheel-drive and very confident drivers should try to tackle the precipitous drops and hairpin turns leading to the bottom. The average grade is 25% and the peak grade reaches 40-45%. In some places this valley is steeper than the Baldwin Street, in Dunedin, New Zealand and Canton Avenue in Pittsburgh, which are considered as the world's steepest streets.

Is Waipio Valley Road dangerous?

Driving into Waipi‘o Valley is not recommended for those who aren’t familiar with the road or don’t have appropriate vehicles. Many rental car agreements prohibit traveling down the road. It is restricted to 4x4 vehicles (which you'll need anyway to navigate the unpaved roads on the valley floor), and hikers with strong legs. If you do decide to drive yourself please only do so in a true 4WD car (no AWD) and only if you are comfortable driving on steep and narrow roads with traffic (both ways). Vehicles must descend in first gear, low range, to avoid brake failure. Driving non-4x4 vehicles into the valley can be, and has been, fatal. Survivors may also be unable to get their non-4x4 vehicles out of the valley without an extremely expensive tow. If you don't have a 4x4, there are tours that will take you into the valley and back, or you can hike on the road (a popular option, at least for the young and healthy). Do not even think about taking a regular 2-wheel drive car, as you will burn up your brakes on the way down.

Is the road to Waipio Valley Open?

On February 25, 2022, the County of Hawaii decided to close the road indefinitely due the imminent threat of slope and roadway failure threatening the health, safety and welfare of the people, although locals are suing to reopen it. Now, the popular visitor attraction will only allow residents and lease holders with agricultural businesses into the area. The deteriorating road conditions and occasional rockslides made the already dangerous route even more of a concern for the state.
More info: https://adventureforlessblog.com/travel-guides/waipio-valley-hike-guide
Road suggested by: Gabe Katzman
Pic: Adam Braun