This study investigated the effect of distraction on driving performance for drivers using a touch screen. We evaluated the influence of three secondary tasks on the primary task varying the task duration and the screen position using 16 participants whose ages ranged from the twenties to the fifties. The primary task was car following. There were three secondary tasks: calling out numbers on the touch screen, calling out numbers and simultaneously to tap the same number on the touch screen, and tapping the four corners of the touch screen. Driving performance was evaluated in terms of speed, headway and lateral position. Based on the results of the study, when the drivers are operating the touch screen while driving, visual and manual distraction differently affected different driving performance measures. Specifically, visual distraction had a greater effect on longitudinal control measure, whereas combined visual/manual distraction affected longitudinal and lateral control measures.