How long the effect of take-over conditions Lasts? a survival analysis of Commercial Motor vehicle drivers’ reaction time and driving behavior in Level 4 of automated vehicles

The transition from automated to manual driving, referred as to Take-over conditions (TOC), in highly automated vehicles (e.g., SAE Level 4 or higher) is a subject of great interest to driver’s safety researchers, considering advancement of automotive technologies. While the literature has focused primarily on the post-take-over behavior of passenger car drivers, assessing different aspects of Commercial Motor Vehicle (CMV) drivers’ post-take-over behavior has received less attention, although it is anticipated that CMVs will be the first to vastly adopt highly automated technology. This paper aims to address the question of how long the effect of TOC lasts in CMV drivers and how automated operation duration before TOC, repeated TOC, and driver’s factors (i.e., age, gender, education, and driving history) affect the duration of TOC’s effect. To accomplish this, we designed a 40-minute experiment on a driving simulator and compared participants’ responses to TOC with continuous manual driving to first, assess significant changes in driving behavior indices (e.g., acceleration, velocity, and headway) in different time intervals and second, evaluate the survival patterns of unsafe behaviors (e.g., hard brakes, sharp turns, and speeding) over time. Multilevel Mixed-effect Linear Models and Multilevel Mixed-effect Parametric Survival Models are incorporated to assess the duration of TOC’s effects. Results showed that the first 10 s of TOC carries the most significant driving behavior changes while the probability of observing unsafe behaviors reduces significantly after 20 s. The results indicated that the effect of TOC lasts longer in long-automated operations, old drivers, and drivers with bad driving history, while repeated TOCs, showed positive effects on mediating the effect of this transition. The findings of this paper offer valuable insights to automotive companies and transportation planners on the nature of Take-over conditions.