During training they told us to keep an eye out for debris in the road. "Anything in the road might be an IED in disguise. An empty MRE bag, an old tire, even a dead animal. Road debris, like broken concrete, might be an indication that they buried an IED in the area." Be alert, they told us. Suspect any debris in the road.
Then we got there and saw what was on the roads. Debris was everywhere. Broken curbs were abundant, trash lined the streets. I did some volunteer work in New Orleans clearing debris after Katrina. There was more crap on the roads in Iraq.
The thing about hiding IEDs inside of old tires stuck in my mind most for some reason. I nearly shit myself my first mission out, because there was a giant pile of old tires just a couple miles from the entry control point, or ECP. Thousands of the fucking things just a few feet off the road.
Eventually you figure out what's supposed to be there and what isn't, but those first few times out were somewhat harrowing, not in spite of our training but BECAUSE of it.