Definition of simulated driving tests for the evaluation of drivers' reactions and responses

Objective: This paper aims at identifying the most significant measures in two perception—response (PR) tests performed at a driving simulator: a braking test and a lateral skid test, which was developed in this work. Methods: 48 subjects (26 females and 22 males) with a mean age of 24.9±3.0 years were enrolled for this study. They were asked to perform a drive on the driving simulator at the University of Pisa (Italy) following a specific test protocol, including 8–10 braking tests and 8–10 lateral skid tests. Driver input signals and vehicle model signals were recorded during the drives and analysed to extract some measures, such as the reaction time, the first response time, etc. Following a statistical procedure (based on ANOVA and post-hoc tests), all test measures (3 for the braking test and 8 for the lateral skid test) were analysed in terms of statistically significant differences among different drivers. The presented procedure allows to evaluate the capability of a given test to distinguish among different drivers. Results: In the braking test, the reaction time showed a high dispersion within the results of the single drivers, leading to just 4.8% of statistically significant driver pairs (using the Games-Howell post-hoc test), whereas the pedal transition time scored 31.9%. In the lateral skid test, 28.5% of the two-by-two comparisons showed significantly different reaction times, 19.5% had different response times, 35.2% had a different second peak of the steering wheel signal and 33% showed different values of the integral of the steering wheel signal. Conclusions: For the braking test, which has been widely employed in similar forms in the literature, it was shown how the reaction time, with respect to the pedal transition time, can have a higher dispersion due to the influence of external factors. For the lateral skid test, the following measures were identified as the most significant for application studies: the reaction time for the reaction phase, the second peak of the steering wheel angle for the first instinctive response and the integral of the steering wheel angle for the complete response. The methodology, which was used to analyse the test measures, was founded on statistically based and objective evaluation criteria and could be applied to other tests. Even if obtained with a fixed base simulator, the obtained results represent useful information for applications of the presented PR tests in experimental campaigns with driving simulators. Supplemental materials are available for this article. Go to the publisher's online edition of Traffic Injury Prevention to view the supplemental file.