The cognitive workload of a steering task could reflect its demand on attentional as well as working memory resources under different conditions. These respective demands could be differentiated by evaluating components of the event-related potential (ERP) response to different types of stimulus probes, which are claimed to reflect the availability of either attention (i.e., novelty-P3) or working memory (i.e., target-P3) resources. Here, a within-subject analysis is employed to evaluate the robustness of ERP measurements in discriminating the cognitive demands of different steering conditions. We find that the amplitude of novelty-P3 ERPs to task-irrelevant environmental sounds is diminished when participants are required to perform a steering task. This indicates that steering places a demand on attentional resources. In addition, target-P3 ERPs to a secondary auditory detection task vary when the controller dynamics in the steering task are manipulated. This indicates that differences in controller dynamics vary in their working memory demands.