The integration of devices within cars is continuously evolving, enabling us to interact with them to an increasingly greater extent. This has transformed the way we drive, communicate and access information on the go. Despite this, there is a lack of research on how to guarantee driver safety while interacting with these systems, especially when looking at in-car systems used in professional settings as a work tool. This master's thesis was conducted in collaboration with NIRA Dynamics and aimed to investigate how the interface of in-car touch screen work tools can be designed to ensure usability and safety for the driver. The study included development of a prototype in the form of a new touch screen interface for a data acquisition system which was used by NIRAs test drivers for the purpose of testing their products. The prototype design was developed iteratively based on the test drivers' opinions as well as theory about important design aspects related to designing in-vehicle systems for high safety and usability. The resulting prototype was evaluated using the System Usability Scale in order to compare the prototype to the original system design and asses to what extent the new interface contributed to increased safety for the driver. The study revealed that some of the main issues that needed to be taken into account in the prototype design were prioritization of information, placement and gathering of elements and reduced amount clicks and scrolling. The final usability evaluation was conducted through user tests and the results indicated that the usability of the prototype was higher than for the original system design, thereby indicating an increased safety for the driver. Overall, this thesis contributes to the research on mitigating the risks of drivers related to interaction with in-car software systems.