How to say “Why are these traffic lights always this slow? I've been standing here for three minutes.” in Japanese

In Japanese

なんでこの信号(しんごう)、いつもこんなに変(か)わるのが遅(おそ)いの？もう三分(さんぷん)も待(ま)ってるんだけど。

Nande kono shingō, itsumo konna ni kawaru no ga osoi no? Mō sanpun mo matterun da kedo.