2.5. Driving Ability Measurement
Several studies on driving ability have used driving simulators. However, certified driving test engineers commonly perform driving ability tests legally conducted in Japan. An accredited driving test operator is designated by the Japan Public Safety Commission and issued a driving test operator qualification certificate under Japan’s Road Traffic Law. Furthermore, the tests were conducted at designated driving schools and on “public roads”. In this study, field tests were conducted to measure driving ability.A challenge in skill tester evaluation is standardizing the calibration or assessment level. To mitigate this, measurement quality was upheld through adherence to Japanese regulations. Technicians responsible for measurement and evaluation were qualified, consistently trained in testing techniques, and reaffirmed scoring criteria before study measurements.A driving ability test was conducted for each participant at a driving school. After confirming the participant’s identity, the following steps were taken to confirm their health condition: explanation of the measurement schedule; proof of the research measurement course; confirmation of vehicle used. Subsequently, the examiner measured the participants on public roads. The measurement was completed with a recheck of the health condition after completing the measurement. Fifty minutes per participant were allotted for measurement. The measurement was conducted with the participant driving the designated test course for approximately twenty minutes, with the skilled test engineer riding in the passenger seat. All the participants were assessed using the same test course. The same test course was used for the pre-and post-intervention measurements.The measurements were conducted on public roads, with safety as the foremost consideration across all measurement aspects. The testers agreed that if driving was considered extremely dangerous from a safety management standpoint, the vehicle would stop and the measurements would be terminated at that point. In these instances, retests were not conducted and data from research collaborators who stopped or suspended measurements were excluded from the analysis.Driving behavior consists of three elements: “cognition”, “judgment”, and “operation [The evaluation method was classified into the “recognition”, “judgment”, and “operation” phases, and one point was added when a point reduction item was identified for each phase. During the measurement period, no approaches, such as reminders from the examiner, were implemented even when a point reduction item occurred.During real-time driving, driving behaviors unfold seamlessly, with the potential for concurrent impact on “cognition”, “judgment”, and “operation”. Alongside individual score evaluations, three categories of composite items were included in the analysis: “cognition” + “judgment” score evaluation, “judgment” + “operation” score evaluation, and “cognition” + “judgment” + “operation” score evaluation.In this study, the driving ability evaluation was based on a point reduction system; therefore, the higher the number of points for each phase, the lower the driving ability level.