過去颱風的長浪曾在台11線公路造成災情。例如2015年蘇迪勒颱風和2018年潭美颱風期間出現路基掏空，而2016年梅姬颱風期間則有浪襲道路的情況。本年度的工作主要利用COBRAS及XBeach等數值模式在台11線人定勝天路段7處斷面的外海設置不同水深位置的離岸潛堤，藉由情境模擬颱風長浪對沿岸的衝擊來分析長浪溯上距離以及長浪作用力的影響範圍。模擬所得的結果可幫助瞭解颱風長浪對公路沿岸造成的影響，並參考花蓮海岸二級防護計劃來研擬此區域的海岸防護因應對策。
亦使用最佳內插法將花蓮、蘇澳和臺東等氣象局的近岸浮標觀測資料對交通部運輸研究所港灣技術研究中心的示性波高預報值進行資料同化以改善花蓮海岸公路浪襲預警系統的輸入值，藉以精進系統的預警能力。另外由於台11線新社段44K附近較容易受到浪襲影響，故利用COBRAS模式針對該路段的3個道路斷面進行不同海況條件的浪襲模擬，藉以建立的浪襲情境資料庫，並將資料庫加入花蓮海岸公路浪襲預警系統以提供相關單位更全面的災害評估。

In the past, the typhoon abnormal waves have caused disasters in Number 11 Highway. For instance, the fundations of Number 11 Highway were exposed when the Sudil typhoon (2015) and Trami typhoon (2018) attacked, and there were wave attacks in Number 11 Highway during Megi typhoon (2016). In stage I of this project, Hualian coastal highway warning system has been established by integrating a nearshore ocean prediction system and a nearshore ocean monitoring system. This year, we utilized COBROS and XBeach to simulate long wave impacts in typhoon along seven cross-sections in the existence of offshore submerged breakwaters. The results are helpful for the understanding of long wave on coastal area near the highway in typhoon seasons. Thus, countermeasures can be implicated and the coastal area can be protected with the aid of level-2 coastal protection plan of Hualian coasts.
In the project, the optimized interpolation method is also utilized for data assimilation. Real-time observation from CWB buoys in Hualian, Suao, and Taitung stations are applied to improve the prediction used in the Haulian coastal highway warning system. In addition, because No. 11 high way around Xinshe sect