A Bayesian reference model for visual time-sharing behaviour in manual and automated naturalistic driving
Journal article, 2020

Visual time-sharing (VTS) behavior characterizes an inattentive driver. Because inattention has been identified as the major contributing factor in traffic crashes, understanding the relation between VTS and crash risk could help reduce crash risk through the development of inattention countermeasures. The aims of this study are 1) to develop a reference model of VTS behavior and 2) reveal if vehicle automation influences VTS behavior. The reference model was based on naturalistic eye-tracking data. VTS sequences were extracted from routine driving data (including manual and automated driving). We used Bayesian Generalized Linear Mixed Models for a range of on- and off-path glance-based metrics. Each parameter was estimated with a probability distribution and summarized with credible intervals containing the model parameters with 95% probability. The reference model corroborates previous findings from driving simulator experiments and on-road studies, but also captures the characteristics of on-path and off-path glance behavior in greater detail. The model demonstrated that 1) there was minimal change in VTS behavior due to automation, and 2) the percentage of time that glances fell on-path (PRC) was greater for all routine driving (~80%) than for VTS sequences (~50%). The PRC was the only metric that was sensitive to VTS, but it did not differentiate between manual and automated driving. Our model, by describing a measure of inattention (VTS behavior), can be used in future driver models to improve the computer simulations used to design ADASs and evaluate their safety benefits. Additionally, the model could serve as a detailed reference for inattention guidelines.

naturalistic driving


human factors




Alberto Morando

Chalmers, Mechanics and Maritime Sciences (M2), Vehicle Safety

Trent Victor

Chalmers, Mechanics and Maritime Sciences (M2), Vehicle Safety

Marco Dozza

Chalmers, Mechanics and Maritime Sciences (M2), Vehicle Safety

IEEE Transactions on Intelligent Transportation Systems

1524-9050 (ISSN) 1558-0016 (eISSN)

Vol. 21 2 803-814 8666160

Quantitative Driver Behaviour Modelling for Active Safety Assessment Expansion (QUADRAE)

VINNOVA (2015-04863), 2016-01-01 -- 2019-12-31.

Human Factors of Automated Driving (HFAUTO)

European Commission (EC) (EC/FP7/605817), 2013-11-01 -- 2017-10-31.

Areas of Advance


Subject Categories

Transport Systems and Logistics

Infrastructure Engineering

Vehicle Engineering



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