How to effectively use the bear traps?

I'm playing campaign mode for Black Ops 2, and I've come to the point in the Pyrrhic Victory mission that grants me the bear traps from the small wooden shed.

I've placed the bear traps around the pathway, but they don't exactly seem to slow anyone down. Is there an effective location to place the traps that will make the mission easier? Also, are the traps able to hurt me?