## 7 Discussion (Study 2)  
It is well documented that driving risk is greatest for teen and senior drivers [59]. The purpose of Study 2 was to investigate driving simulator performance differences between teen and senior participants using only FOD-A combination 3. For this reason, the results and conclusions from Study 2 cannot automatically be generalized to all other FOD-A possible combinations. A sample of 21 teens and 34 seniors, completed FOD-A combination 3. All participants were measured on 13 driving simulator performance variables. The results revealed noteworthy differences between the two groups on these performance variables: Average target E reaction time, standard deviation of target E reaction time, number of target E extra presses, and standard deviation of brake reaction time. Seniors reacted slower when responding to the target Es, had greater variability when responding to the target Es, and had a greater number of extra presses when responding to the target Es. These findings reaffirm previous literature that has documented age-related changes that impact driving, such as cognitive and physical decline [60]. Regarding the task of responding to the lead vehicle's brake lights, the results were similar: Seniors had more variance on the standard deviation of brake reaction time relative to teens. It was noted that the number of extra presses, standard deviation of brake reaction time, and average target E reaction time had particularly large effect sizes. Performance on these specific variables is suggestive of the subject's processing speed, notice and response time, scanning, and attention. This illustrates that senior populations are susceptible to issues concerning reaction time. Although only three variables had a sizable effect, all four significant variables were used in the LDA. The results of the LDA suggest that the four variables can be ordered from largest to smallest contribution as follows: standard deviation of brake reaction time, number of target E extra presses, average target E reaction time, and standard deviation of target E reaction time. Of the four variables, the standard deviation of brake reaction time maximizes differences in driving simulator performance between teens and seniors the most. Conversely, the standard deviation of target E reaction time accentuates the differences in driving simulator performance between teens and seniors the least of the four variables. Using all four variables, the LDA can accurately determine the age group of a participant solely from their performance on four variables approximately 78% of the time. Stated differently, if a clinician only had the results of these four variables, this model could accurately predict if they were a teen driver or a senior driver with around 78% accuracy. Given the imminent need for interventions to target the growing aging driving population, this study demonstrates the value in exploring the multiple factors that affect and impair driving capabilities. The advancement of this study lies in the application of the Functional Object Detection--Advanced (FOD-A) tool, which provides clinicians with a uniquely configurable and objective method for evaluating complex driving skills, such as reaction time, visual scanning, and motor control. FOD-A allows for the customization of task difficulty, enabling personalized assessment and rehabilitation pathways that align with individual client needs. By implementing methods like linear discriminant analysis (LDA) to rank task difficulty, clinicians can use a research based approach to select appropriate scenarios to address their clients' needs in a time efficient manner. This approach facilitates targeted skill assessments, especially valuable in clinical settings with time constraints, providing a robust framework for assessing physical functioning, cognition, and vision skills quickly and objectively using tasks that directly relate to the driving context.