A hazard-based model of the motorcyclists' overtaking duration

The overtaking maneuver performed by motorcyclists is one of the primary causes of motorcycle accidents. However, few studies in the literature deal with this topic and there are no studies modeling the total overtaking duration, i.e. the time during which extreme hazards are manifest. The present paper aims to analyze the motorcyclists' behavior during overtaking and to model the total overtaking duration. A field experiment, using instrumented motorcycles, was performed to collect data and a survival analysis was carried out to model the total overtaking duration. Twenty young motorcyclists drove their own motorcycles, which were instrumented with a camera and a global positioning system device (GPS), onto a two-lane suburban road in Rome. A total of 101 overtaking maneuvers were recorded. A methodology, based on video and GPS analyses, was developed to obtain data describing the motorcyclists' behavior. The obtained results showed that the mean values of the main parameters of the overtaking maneuver (total overtaking duration - 6.6 s - and distance - 109.7 m - lateral distance from the passed vehicle - 1.50 m) were consistent with the few data available in the revised literature. The total overtaking duration was modelled using a hazard-based duration model. The parametric accelerated failure time duration model with a log-logistic distribution, which was the best-fitted distribution, identified the covariates which affected, in a statistically significant way, the total overtaking duration. The obtained model revealed that the overtaking duration depends on several covariates. The greater average impact was found for the initial distance and speed difference, while the initial lateral distance and final distance produced a minor impact. When performing a multiple overtaking, the duration of the maneuver tended to increase by 31 %. This research can be considered as a pilot study and a starting point for future advances on motorcyclists' behavior during overtaking maneuver and for modeling the total overtaking duration. In addition, the findings of this study could contribute to the development of advanced rider assistance systems for the overtaking maneuver based on current driving conditions.