  Manipulating MW in driving simulator studies without the need to introduce a
non-driving-related task remains challenging. This study aims to empirically
evaluate the modified speed regulation n-back task, a tool to manipulate
drivers' MW. Our experiment involved 23 participants who experienced a 0-back
and 2-back driving condition, with task-irrelevant novel environmental sounds
used to elicit P3a event-related potentials. Results indicate that the 2-back
condition was perceived as more demanding, evidenced by higher NASA-TLX scores
(overall score, mental and temporal demand, effort, frustration). The mean P3a
amplitude was diminished during the 2-back condition compared to the 0-back
condition, suggesting that drivers experienced higher MW and had fewer
resources available to process the novel environmental sounds. This study
provides empirical evidence indicating that the speed regulation n-back task
could be a valid, effective, and reproducible method to manipulate MW in
driving research.
