The development of active safety systems in vehicles is a complex task and requires rigorous and precise testing. This testing needs to be done both by scripted/Automated tests such as HIL (Hardware in loop) and real life in target system validation. This thesis presents modern visualization tools to manage and analyze relevant test data. The project began with a pre-study phase, where interviews were conducted to elicit requirements for such a system. These were then applied over two iterations of development of both a low- and high-fidelity prototype. The end result was Theia, an easy-to-use tool to evaluate the performance of cameras and sensors with recorded vehicle data. Theia was then evaluated through a series of user tests, which concluded that it was an effective way to design such a system. Furthermore, the strategy to use for developing a modern such system, and how to prioritize relevant visualization data were also formulated.