The development of autonomous driving technology has led to the gradual deployment of higher levels of autonomous driving. In such systems, multi-task scenarios and abrupt task transitions require drivers to process and manage more information quickly, resulting in information overload. Augmented Reality (AR) technology and Heads-Up Displays (HUDs) are effective tools for alleviating this overload. This study examines the effect of AR display variables on user work performance in autonomous driving task switching scenarios through an AR simulation experiment. Transparency, a key variable in AR display design, was selected in this study. Task completion efficiency was measured under scenarios with or without task switching. The experimental results indicate that users’ work efficiency is higher within the moderate transparency range (T0.8, T0.6). The addition of task switching significantly increased task completion time. However, the high transparency range (T1.0) helped reduce the impact of task switching.