Studies on solar electric vehicles (EVs) have focused on calculating the power generation in a specific environment without discussing its practical utility. To expand the awareness of the utility of solar EVs, their potential should be evaluated by considering the operation methods of users. This study investigated the photovoltaic (PV) potential of an EV integrated with PV modules while driving on an expressway. Tunnel and shadow areas were identified to determine unpowered areas on the expressway. The PVWatts model was used to evaluate the PV potential by the time of the year. For a single vehicle traveling at 60 km/h on the Donghae expressway section during both the summer and winter solstices, the amount of power generation is within 0.208–0.317 kWh, corresponding to 0.94–1.43% of the electricity consumed for driving. Furthermore, this study assumed that office workers commute on the Donghae expressway. Under the scenario considering the time of operation (traveling to and from work and parking at work) and the shading ratio, the rechargeable amount was more than 10% of the electricity consumption. The results showed that solar roofs are potential charging supplements for EV batteries. This study can provide the efficacy and optimal operation method of solar EVs for commuters.