Andean High-Plateau Corridors
The Andean Cordillera stretches over 7,000 kilometers along the spine of South America, hosting transit routes that stay above 4,000 meters for days at a time. Here, high-altitude passes are not merely short notches between adjacent valleys; they are gateway crossings into the windswept, hyper-arid Altiplano and Puna deserts.
1. Paso de Jama (4,200 m / 13,780 ft) – The Modern Trans-Chaco Link
Connecting San Pedro de Atacama in Chile with Jujuy Province in Argentina, Paso de Jama is an engineering feat of heavy asphalt construction. Leaving the Atacama basin at 2,400 meters, Route 27 ascends continuously for 45 kilometers to over 4,800 meters near the Licancabur volcano before leveling out along the border crest.
Because this route handles international heavy freight (including refrigerated container trucks transporting agricultural goods to Pacific ports), civil engineers maintained gentle 5% to 7% grades. However, the absolute altitude introduces oxygen levels 40% below sea level. Diesel prime movers without twin-scroll turbocharging suffer immense torque drops and emit thick unburned soot as engine control units struggle to trim injection ratios.
2. Paso Internacional Los Libertadores (Caracoles de Chile)
Connecting Santiago de Chile to Mendoza, Argentina, the Chilean approach features 29 numbered hairpins carved into a vertical canyon face known as Los Caracoles. Unlike the high plateau of Jama, Los Libertadores is prone to violent Pacific-generated winter storms.
The route passes through the Christ the Redeemer Tunnel at 3,200 meters. The tunnel was constructed in 1980 to bypass the treacherous gravel road that once climbed to the 3,832-meter crest. Even with the tunnel, heavy avalanche chutes and catastrophic ice build-up frequently shut the highway for two to three weeks each winter, stranding thousands of commercial transport rigs on both sides of the border.
3. Abra del Acay (4,895 m / 16,060 ft) – The Unpaved Giant of Ruta 40
Located in Salta Province, Argentina, Abra del Acay is often cited as the highest road pass in the Americas and one of the highest on Earth outside the Himalayas. It remains an unpaved, single-track route with sheer unprotected drops and unstable slate foundations.
During the southern summer rainy season (January to March), flash floods carve deep ruts across the switchbacks. Vehicles attempting the Acay pass require true four-wheel drive with low-range transfer cases, beadlock-capable all-terrain tires, and secondary oxygen canisters for occupants prone to acute mountain sickness (soroche).