In-vehicle information display is critical for driving safety and has been the focus of transportation and display technology research. Cellphone use, while driving is popular, leads to distraction and impairs driving performance. Anew head-mounted display (HMD), GoogleGlass, has been developed in hope of reducing the visual distractions caused by a head-down display (HDD), such as a smartphone. Alternatively, HMD could induce greater distraction by giving drivers the false impression that they are simultaneously paying attention to both the HMD and the road. We compared driving performance in a simulated tactical lane-changing task while drivers read from either an HMD (e.g., Google Glass) or an HDD (e.g., smartphone). Although both HMD and HDD use impaired driving performance, drivers produced smaller lane variation, had fewer lane excursions, and lower subjective workload when using an HMD than when using an HDD. Wearable display technologies like Google Glass might reduce the impairment caused by looking down at a smartphone.