Observing Driver’s Cognitive Load in a Driving Simulator


  • Kaja Ceglar University of Ljubljana


Autonomous vehicles are bound to become a part of our daily lives in the near future and the safety of users is the primary concern of many researchers when trying to incorporate the technology for public use. Fully autonomous vehicles can operate without a human intervention under any conditions. The research question addressed by the research is whether the addition of a Head-up display (HUD) can improve the user experience, perceived usability, user well-being and driving safety, when using conditionally automated vehicles. [1]


The experiment was done in a driving simulator, where participants had to undergo two rides, one using a regular dashboard and a HUD, and the other one only using a dashboard. During the rides, they were asked to turn on autonomous driving, during which, they were able to use their phones, head-down display, read a magazine or just use that time to relax. To avoid learning effects (and sleepiness) on the study results, half of the participants started with the HUD, and half started without it. We measured variables using biometric devices: eye tracker and a smart wristband, the driving data from the simulator. We also observed user experience with four different types of questionnaires. The most important variables were pupil dilation, heartrate responses and skin conductivity. These can then be translated into either cognitive load data or different emotional responses. For example, pupil dilation shows greater cognitive effort. [2]


The data collection and analysis have not been completed yet. The research hypothesis is that the addition of a HUD will result in better scores for the above- mentioned aspects when operating a conditional vehicle compared to a vehicle with only a classical dashboard.

The devices used to measure cognitive load in this study are all indirect. For better results we should track brain activity directly with EEG or other similar methods.


This study is an excellent indicator of what autonomous driving can and is able to become. It’s important that we invest in these preliminary researches before the technology gets on the road and becomes a matter of public safety. Autonomous vehicles will inevitably be a part of our future and every aspect of their use should be thoroughly examined and tested.


This work was financially supported by the European Union’s Horizon 2020 research and innovation program for the project HADRIAN (grant agreement no. 875597).


[1] SAE Taxonomy and definitions for terms related to driving automation systems for on-road motor vehicles, SAE International standard J3016_202104, 2021.

[2] T. Čegovnik, K. Stojmenova, G. Jakus and J. Sodnik, “An analysis of the suitability of a low-cost eye tracker for assessing the cognitive load of drivers”, Applied Ergonomics, vol. 68, pp. 1–11, April 2018.