台灣是一個多山的島嶼，面積約計3,600,618 公頃，其中山坡地總面積計有 2,639,653 公頃，佔全台約73%，也因如此，山區各地區之交通構連，需要公路開 發改善兩地間交通，但也因山區公路開發，擾動自然風貌，所以經常發生坡地破 壞的災害，特別是蘇花公路發生災害紀錄非常多，大多數的災害又與雨量及環境 有關，本研究係收集台九線東澳嶺段現場雨量調查及坡地破壞紀錄歸納分析，建 立降雨指標與坡地破壞關係，找出公路行車安全對策之研究，以確保人員通行安 全及降低災害之發生。

Taiwan is a mountainous island, area of about 3,600,618 hectares, the total area of the hillside is 2,639,653 hectares, accounting for about 73%, also because of this, traffic in the mountainous areas, need road development to improve traffic between the two places, but also because of mountain road development, disturb the natural style, so often the destruction of slopes, nn particular, the Suhua Highway disaster record is very much, most of the disasters are related to rainfall and the environment, This study is a summary of the field rainfall survey and the record of the damage to the slope, establishment of relationship between rainfall index and slope failure, study on the countermeasures of highway traffic safety, to ensure the safety of personnel and reduce the occurrence of disasters.