The Steepest Road in the World, Plus 9 Rival Inclines

The Guinness World Records determines the steepest street by measuring the maximum gradient over a 32.8-foot (10-meter) horizontal distance. This method ensures a fair assessment by focusing on the steepest continuous section, rather than averaging the incline over the entire length, which could dilute the extremity of the slope.

In 2020, Guinness World Records updated its measurement criteria to base the gradient on the central axis of the road, when Ffordd Pen Llech in Harlech, Wales, claimed the record in 2019, and those advocating for the previous record holder Baldwin Street in Dunedin, New Zealand, appealed the decision.

Baldwin Street in Dunedin, New Zealand, initially held the title of the world’s steepest street with a gradient of 34.8 percent. Ffordd Pen Llech in Harlech, Wales, had claimed the record with a reported gradient of 37.5 percent.

But under this revised measurement method, Ffordd Pen Llech’s was determined to be 28.6 percent, and Baldwin Street regained its title as the world’s steepest street in April 2020.

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