A method of a layout diagram (of a conductive line structure for an IC) including: for a first set of pillar patterns included in an initial layout diagram that represents portions of an M(i) layer of metallization and where i is a non-negative number, the first set including first and second pillar patterns which are non-overlapping of each other, which have long axes that are substantially collinear with a reference line, and which have a first distance of separation, determining a first distance of separation as between corresponding immediately adjacent members of the first set; recognizing that the first distance is less than a transverse routing (TVR) separation threshold for an M(i+j) layer of metallization, where j is an integer and j≥2; and increasing the first distance so as to become a second distance which is greater than the TVR separation threshold of the M(i+j) layer.