https://blog.wongcw.com/2019/03/07/%e8%87%aa%e4%be%9b%e9%9b%bb%e6%99%ba%e8%83%bd%e5%81%9c%e8%bb%8a%e6%a8%99%e8%aa%8c%e9%80%9a%e9%81%8e%e9%bb%9e%e4%ba%ae%e9%96%83%e5%85%89%e7%87%88%e4%be%86%e6%8f%90%e9%86%92%e7%be%8e%e5%9c%8b%e8%be%b2/
自供電智能停車標誌通過點亮閃光燈來提醒美國農村司機