One estimate is that 200-300 travellers were killed yearly along the road. The road includes Christian Crosses marking many of the spots where such vehicles have fallen. Upon leaving La Paz, the road first ascends up to around 5 km, before descending to 330 m (1079 ft), transitioning quickly from cool altiplano terrain to rain forest as it winds through very steep hillsides and atop cliffs.
The road was built in the 1930s during the Chaco War by Paraguayan prisoners. It is one of the few routes that connects the Amazon rainforest region of northern Bolivia, or Yungas, to its capital city.
Because of the extreme dropoffs, single-lane width, and lack of quardrails, the road is extremely dangerous. Further still, rain and fog can make visibility precarious, the road surface muddy, and loosen rocks from the hillsides above.
On July 24th, 1983, a bus veered off the Yungas Road and into a canyon, killing more than 100 passengers in what is said to be Bolivia's worst road accident. One of the local road rules specifies that the downhill driver never has the right of way and must move to the outer edge of the road.
This forces fast vehicles to stop so that passing can be negotiated safely. Also, vehicles drive on the left, as opposed to the right like the rest of Bolivia. This gives the driver in a left-hand-drive vehicle a better view over their outside wheel, making passing safer.
The danger of the road ironically made it a popular tourist destination starting in the 1990s. Mountain biker enthusiasts, in particular, have made it a favorite destination for downhill biking, since there is a 64 km stretch of continuous downhill riding.
Travel at night is considered less dangerous than in the day because drivers can see the headlights of oncoming traffic. But the downside to nighttime travel is that downhill-bound vehicles often drive off the side of the road while backing up to allow uphill-bound vehicles to pass.
Some drivers refuse to back up. Others play games of chicken. "It's the young, inexperienced drivers that cause the accidents," said Rudy Quezpert, a bus driver who had stopped at a police checkpoint.
Despite the Yungas Road's appalling accident toll, no ambulance crew is stationed closer than La Paz, two hours' drive away.
