Passo San Boldo

San Boldo Pass, a military road with 18 hairpin turns and 5 tunnels

Passo di San Boldo is a mountain pass at an elevation of 712m (2,335ft) above the sea level, located in the province of Treviso, Veneto, in north-eastern Italy. The road to the summit is an engineering masterpiece with 18 hairpin turns and 6 tunnels. It’s one of the famous hairpinned roads in the world.

Is the road to San Boldo Pass paved?

Set high at the southern edge of the Italian Alps, the road to the summit is totally paved. It’s called Strada Provinciale 635 (SP 635). The pass is 11.6km (7.20 miles) long, running south-north from Tovena to Sant'Antonio Tortal. The most challenging part of the climb is a short stretch of 700m with 5 five tunnels blasted into the rock with 8 numbered hairpin turns and six bridges. The road just allows traffic in one direction, alternating with traffic lights. There is a speed limit of 30 km/h (19 mph) and a height limit of 3.2 m (10.5 ft), after buses were repeatedly stuck in the tunnels.

When was the road to San Boldo Pass built?

This road is usually open all year, but can be closed anytime when the access is not cleared of snow. This road has always had a considerable historic importance. It dates back to Roman times. The road replaced a steep path leading up to summit that existed since the nineteenth century but only during the First World War that project succeeded. Between February and June 1918, the Austro-Hungarian army managed to build the road in less than three months. After this fact, the road got the nickname of "road of 100 days." 1400 people, including prisoners of war and women, children and the elderly in the area, worked day and night to complete the strategic route for refueling during the Battle of Piave. Despite the topographical conditions, the slope could not exceed 12% for the passage of heavy vehicles and artillery. The works began in 1914 under the direction of engineer Giuseppe Carpenè.

How the pass got its name?

The road is brutally steep in parts, hitting a 37% of maximum gradient through some of the ramps. The drive features 18 hairpin turns. Despite the fact that the road is located in Italy, it’s named after a Spanish hermit, called Boldo. He was a hermit living in these mountains and some years late he would become saint, San Boldo.
Pic: Solitario Motero


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