This "Don't Honk" sign can be well effected especially for people that honk a lot. The use of red frame is a sign of warning and stopping. As you can see, the color of the frames are inverted showing a sense of consequence after honking. This sign is very clear about what it wants you to do - it wants you to "NOT" honk. Generally, people who follow the law and care about the society (or how the society judges them) will simply follow this sign. The sign does not need any extra graphics or words to show what it wants you to do. I guess the down side of this sign is when you "DON'T" see it!
This recycling sign, is on the poll in the same position as the "Don't Honk" sign. On the other hand, I find this sign less effective because the words were small and the color is boring. The position of the sign makes it hard to be noticed when people are walking down the street. I noticed that a lot of recycling signs that attract my attentions are the ones with color. Ex. "Green" is the color of "Helping the earth!", "Red" is the color of "STOP IT!". It isn't a particular bad designed sign, it just didn't trigger me to do more recycling than I am already doing.