The spread of smartphone has enabled everyone to easily participate in information activities regardless of time and space. The interiors of cars are not an exception to this phenomenon. Many drivers use their smartphone while driving, though it is legally restricted due to safety issues. This research intends to (1) observe the information behaviors of drivers (2) classify their information activities (3) and finally induce design implications. For this purpose, we conducted user research using an in-car monitoring system observing drivers in situ (Figure 1) and a smartphone application usage tracker. After gathering and integrating the data through a multi-coding process, we were able to introduce special categories, "five sessions," explaining a smartphone usage pattern in cars particularly. Moreover, using the drivers' voice recordings, we found out drivers' specific informational needs. The results informed us of four implications that could be used in smart cars or car-related services in the future.