Southern Cross-Island Highway Tianchi-Yakou Section: A High Mountain Road Crossing the Central Mountain Range

The Highland Highway Reopened After Years of Dormancy

The Southern Cross-Island Highway (Provincial Highway 20) was severely damaged by Typhoon Morakot, and was reopened in sections over many years. The core high-mountain section on the western side, from Meishankou to Yakou, spans about 45 km, with the highest point at Yakou Tunnel reaching an elevation of approximately 2,722 meters—one of the highest points on Taiwan’s highways, second only to Wuling. Its biggest difference from Wuling is that it is “sparsely trafficked and feels profoundly wild.”

Section Data

Acclimatization Is Key

From Tianchi to Yakou, you enter elevations above 2,300 meters, where some people may experience mild altitude sickness. It is recommended to stay overnight at Tianchi (Xiangyang) for acclimatization, then attack Yakou early the next morning—this can greatly reduce discomfort.

Recognizing and Responding to Altitude Sickness: A Checklist

The Yakou section of the Southern Cross-Island Highway crosses above 2,000 meters, making acute mountain sickness (AMS) more likely than most people imagine. Here is the assessment and response protocol every long-distance rider should memorize:

• Mild (may continue but must slow down): headache, nausea, slight breathlessness—immediately reduce pace, drink more water, slow your breathing rhythm; most people recover after acclimatizing
• Moderate (must stop ascending): persistent vomiting, unsteady gait, severe headache—rest in place; if there is no improvement, “descend in elevation”—descending is the most effective remedy
• Severe (emergency): confusion, coughing pink frothy sputum, severe breathing difficulty—descend immediately and call for help; these are precursors to pulmonary/cerebral edema and must not be pushed through

Three prevention principles: stay overnight at Tianchi (approx. 2,280 meters) the night before to acclimatize; on the day of the climb, eat and drink small amounts frequently (at least 500 ml per hour); and treat a 10% to 20% slowdown in pace above 2,500 meters as normal—do not force intensity.

Traffic Control Notes

The western and eastern sections of the Southern Cross-Island Highway are opened on a scheduled basis, and some sections still have temporary roads and checkpoints. Be sure to check the latest opening schedule from the highway authority before departure—missing the window may result in being stopped. Cell phone signals are unreliable in the mountains, so bring offline maps for your trip.

Supply Status

• Meishankou: the last full resupply point—stock up completely
• Tianchi/Xiangyang: mountain huts and basic supplies, limited quantities
• After Yakou (eastern section): supplies are extremely scarce; it is recommended to carry enough energy gels and water

Climate and Gear

Temperatures at Yakou can approach 0°C in the early morning; even in summer, you need to bring a windbreaker and full-finger gloves. UV radiation at high altitude is extremely intense—lip balm and sunscreen are essential. It is recommended to use a cassette with 36 teeth or more paired with a compact crankset to handle the sustained long climbs.

The Southern Cross-Island Highway is not for people who ride it just for a photo check-in. It demands that you respect the traffic controls, respect the altitude, and respect the wounds this mountain has endured. To ride across it quietly is a privilege granted by the mountain.

Related Reading

• Riding the Southern Cross-Island Highway: Taiwan’s Most Magnificent Cross-Island Cycling Experience
• Westbound on the Southern Cross-Island Highway: From Meishankou to Tianchi, a Ride Through Resilience, Bunun Mountain Forests, and Cloud-High Lakes
• Taiwan Long-Distance Cycling Routes: Mountain Riding on the Southern Cross-Island Highway
• Southern Cross-Island Highway Reopens: Cycling Conditions After Provincial Highway 20 Resumed Traffic