What is an アイドリングストップ?

  I often see signs in Japan that say, "Idling stop." For years, I thought it meant (意味する） that you should idle your car when you stop at a traffic light (交通信号灯).
 It's confusing (分かりにくい) because in English, we say a "short stop" (にちょっと立ち寄る), a "rest stop" (休憩), or a "regular stop" (正常停止). Idling stop sounds like "エンジンをアイドルしながら停止する）.
 Recently (最近）, I found out that アイドリングストップ　means the opposite (反対）. The correct way to say アイドリングストップ is "No idling".

Here are some common signs. Do you know what they mean? The answers are in the comments.
No smoking.
No trespassing.
No parking.
No littering.
No dumping.
No soliciting.