Colla d’Onzo, a grueling unpaved road to the summit
Colla d’Onzo is a mountain pass at an elevation of 843m (2,765ft) above the sea level, located in the Province of Savona in the Italian region Liguria. The climb is simply brutal: 10.24% average gradient.
The road to the summit is not easy: very narrow, steep, and impassable after rains or snow. Not recommended for low clearance vehicles. The road has some narrow parts, impassable for 2 medium cars. Not recommended if you don't know how to reverse.
Starting from Capitolo-Costa, on Strada Provinciale 20 (SP20), the ascent is 4.1 km long. Over this distance the elevation gain is 420 meters. The average gradient is 10.24%.