请教11th-Review 44关键句子的语法结构

Laws requiring the use of headlights during daylight hours can prevent automobile collisions. However, since daylight visibility is worse in countries farther from the equator, any such laws would obviously be more effective in preventing collisions in those countries. In fact, the only countries that actually have such laws are farther from the equator than is the continental United States.

请问有没有人知道黄色部分这句话的意思和语法结构，该句来自11th-Review 44, OG的解释是：The only countries having these laws are those located farther from the equator than is the continental U.S,谢谢。