Hairpin turn

Under a Serpentine refers to a scale in a serpentine path or a road that in many curves and hairpin bends winding up a mountain slope in a zig - zag course.

First one called simply " that crook of a river, which is repeated by the same often in opposite directions, so that it mimics the character of the letter S" Serpentine. The term comes from the Latin serpent ( = snake). Then the paths on hillsides were so designated as wavy lines.


The plant of serpentine extends the distance compared to a more direct connection and thus allows to overcome the same height difference with lower slopes. Driving or walking on a steep slope is often possible only by the investment of serpentine, which, however, because of the erosion and slipping requires a good, frost-proof underground and careful construction.

The " curve radii " of climbing in the mountains are irrelevant for the climber, but not for the earth. It erodes the more so the longer the bare ground running in the fall line. A trail in a very narrow zig -zag up the hillside, experienced mountain hikers can some Serpentine also " cut off " and thus create a starting point for the erosion.


Older mountain paths were traced out with maximum slopes of about 3 percent, because it provides the friction of the drive wheels is not large enough for safe operation on the rails. To the terrain well adjust the route, that is the construction with as few moving earth ( dams, cuts ) perform tight turning radii are required. Are these the other hand, less than about 200 meters - which is almost inevitable in sharp turns - this reduces the possible speed, leaving the driving resistance grow strong.

Individual serpentine are often applied even when the crossing of a valley, with a longer course of the traffic route is connected on each side of the valley with a significant height gain. For example, the Semmering Railway, whose track alignment 1854, the first in the high mountains, was a few miles out into the valley to Payerbach, crosses the valley on a curved bridge and opened up the subsequent health resort only for tourism. During construction of the Black Forest Railway were first built on a larger scale helical tunnel, with those of the corresponding height gain in narrow valleys is possible.

Road construction

In road construction, some high -pass roads are traced out with dozens of switchbacks; for example, the Silvretta road has 32 ​​hairpin bends, because she had to provide a suitable entry and exit also the heavy traffic during the construction of the power plants at Silvretta reservoir. The Serpentine is announced, normally by a traffic sign and especially numbered on roads used by tourists from the valley to the pass, sometimes obtain single serpentine your own name. In rare cases, run in serpentine tunnels, such as the Italian Passo San Boldo or in the Malta Valley, or on bridges.

In forest goods and infrastructure within the mountains, the minimum radii are traditionally at about 5 to 10 meters, but were their serpentine expanded in recent decades, mostly for driving with heavy machinery. Because this increases the risk of landslides -branches and wind break, one has become a little more cautious with such expansion since the 1980s.

Known serpentine roads

Bends of the Georgian Military Highway

The Via Krupp on Capri