Up the back-side ramp close to where the truck comes in in the base game, this location is in a little alcove just as you finish climbing.

Toward the middle of the map, this location is just on the overpass.

From the previous, this check is at the gate directly adjacent.

Turn around from the previous and you can see this location on the opposite side.

This check is at the highest part of the map, on the hilltop.

These two checks are inside the two buildings you can enter on the map. First screencap is from the higher of the two. Second is from the lower.