PURPOSE: This study compared on-road driving performance using paper directions versus GPS. A second question compared wayfinding performance between on-road driving and driving in an interactive driving simulator (IDS). Typical clinical assessment tools (Trail Making Test B [Trails B], Assessment of Motor and Process Skills [AMPS], Useful Field of View [UFOV]) were also compared with driving outcomes.

Driving is a fundamental instrumental activity of daily living (IADL), and occupational therapists (OTs) need practical, effective tools to evaluate clients’ fitness to drive. To be proficient at driving, one needs competency on the operational (manipulating pedals, steering wheel), tactical (negotiating obstacles), and strategic (navigation) levels. Few studies explore the strategic level. It is beneficial to determine if the strategic level of driving can be evaluated without an expensive, lengthy on-road test.

DESIGN: A cross-sectional quasi-experimental design was used. Counterbalancing testing order of simulated driving and on-road driving of two unfamiliar routes yielded eight conditions. Participants were 24 volunteer drivers, ages 18–45 yr. They established norms to be compared with a forthcoming National Highway Transportation Safety Administration study with 80 older drivers.

METHOD: Clinical assessments (AMPS, Trails B, and UFOV) measured aspects of executive function, a critical client factor for wayfinding. IDS evaluation involved wayfinding scenarios on STISIM software. Following acclimatization drives, participants navigated via printed directions on the IDS. Driving performance in the IDS and on road was measured with a modified Miller Road Test, a score sheet adapted from the North Carolina Department of Transportation to coordinate with routes used in this study. In the on-road assessment, all participants drove personal vehicles and used the same Garmin GPS. Demographics, driving habits, and GPS comfort level were collected using a modified Driving Habits Questionnaire and GPS Familiarity Questionnaire.

ANALYSIS: To compare driving performance in different conditions, modified Miller Road Test scores were compared with box plots and a paired t test with a 95% confidence interval. Clinical assessment scores were compared with modified Miller scores on the IDS and two on-road assessments using nine distinct scatterplots. Data collected from the modified questionnaires and demographic information were visually inspected to determine whether demographic factors or driving habits significantly affected scores on each assessment. An independent samples t test found testing order did not make a difference in outcomes.

RESULTS: The modified Miller Road Test scores of participants wayfinding with GPS were significantly better than (p = .024) on-road scores using printed directions. Scores of participants who were wayfinding on the IDS with printed directions did not differ significantly (p = .058) from on-road scores using printed directions. Scores measuring performance while wayfinding on road or in the simulator and the scores of clinical assessments did not have a strong relationship.

DISCUSSION: Results indicate that driving performance is often improved when individuals receive directions from a GPS. Significant links between scores on the IDS and on-road driving tests suggest the simulator can be used to evaluate wayfinding (strategic level). Using a simulator for evaluation is a viable, cost-efficient method for comprehensively determining on-road driving fitness.

IMPACT: This study builds a foundation of information about how OTs can assist clients with wayfinding and use simulators to develop wayfinding skills. It contributes to foundational work with older adults and enhances the scientific community’s understanding of on-road wayfinding. Participants will comprehend the need for therapists to address the IADL skill of driving as well as appreciate how and if GPS can prolong older adults’ driving.