A method and computer program product for modeling a semiconductor transistor device structure having an active device area, a gate structure, and including a conductive line feature connected to the gate structure and disposed above the active device area, the conductive line feature including a conductive landing pad feature disposed near an edge of the active device area in a circuit to be modeled. The method includes determining a distance between an edge defined by the landing pad feature to an edge of the active device area, and, from modeling a lithographic rounding effect of the landing pad feature, determining changes in width of the active device area as a function of the distance between an edge defined by the landing pad feature to an edge of the active device area. From these data, an effective change in active device area width (deltaW adder) is related to the determined distance. Then, transistor model parameter values in a transistor compact model are updated for the transistor device to include deltaW adder values to be added to a built-in deltaW value. A netlist used in a device simulation may then include the deltaW adder values to quantify the influence of the lithographic rounding effect of the landing pad feature.