Using the wizard of Oz paradigm to prototype automated vehicles: methodological challenges

Wizard of Oz (WoOz) vehicles are becoming increasingly popular within the human factors research community to prototype automated vehicles in real traffic conditions. With promising results, researchers have so far used the WoOz approach, among other topics, to assess user interfaces, the effect of non-driving related tasks or the development of drowsiness during automated driving. However, a research gap exists considering standardized methodological guidelines for the implementation of WoOz studies in the context of automated driving. In an attempt to fill this gap, this paper investigates the components and their connections in tests using WoOz vehicles. It also applies the three main test quality criteria, objectivity, reliability and validity to the WoOz method. Based on this analysis, methodological challenges are discussed in detail and necessary research questions are deduced. Both challenges and research questions may serve as a thought-provoking impulse when designing WoOz studies in the future.