<p>Young, middle and older drivers were motored towards a traffic signal face and were required to report whether the illuminated signal lens was modulating. No significant differences were found among the three age groups in the distance at which modulation was first reported nor in the change of the modulation pattern as they approached the signal face. The modulating of the illuminated green lens was percieved signifcantly further away than was the red lens. These distances increased during trials associated with inclement weather. Seventy-four percent of the observers indicated that the modulation attracted their attendtion. Of these, 64% reported a preference for the user of the modulating light in the traffic signals as compared with the standard light source. Implications for improving safety at intersections for the older driver are discussed.</p>