1 googled : 限速區區域在您到達標誌處生效。

1 googled (https://www.wadenapj.com/opinion/columns/4474157-ask-trooper-where-does-speed-limit-change-near-signs#:~:text=see%20the%20sign%3F-,Answer%3A%20The%20speed%20limit%20zone%20area%20becomes%20effective%20at%20the,sign%20before%20increasing%20your%20speed). The speed limit zone area becomes effective at the point you reach the sign.  

 

The point I want to make is that I have reached the sign yet.