Land of the Giants - episode "Brainwash" (1968)
Character played:  Officer 778

Officer #778 is walking his beat when he stops to tie his shoe right by where they are hiding.

As he moves away from the hydrant, he stumbles across the scrap piece of wire
 that the little people were scavenging and catches a brief glimpse of them from the
 corner of his eye.  They escape as he is slowed by traffic.

He searches all around for them, even looking down into a storm drain.

He can't spot them in the dark pipe so he reports back to his superiors.