Towards a definition of safety for individual drivers lane behavior

To assess lateral control performance in drivers, lane behaviour indicators such as the mean lane position, standard deviation of lane position and time-to-line-crossing are the most frequently used measures. For lane position, the commonly accepted (qualitative) proposition is that increased lane swerving indicates reduced vehicle control and hence a decreased level of safety. For time-to-line-crossing, a rule of thumb is that a value of less than 1s implies a decreased level of safety (e.g. an increased risk of lane exceedance). However, a quantitative relationship with safety similar to the one between speed and safety or between speed variability and safety does not yet exist for lane behaviour indicators. In the current study, we intend to establish a link between this type of driving behaviour in individual drivers and the level of safety, using data from both studies related to impaired driving and studies not related to impaired driving. The results from this study can be a first step in ultimately setting cut-off values for safe driving based on individual behavioural indicators