Do adaptive cruise control and lane keeping systems make the longitudinal vehicle control safer? Insights into speeding and time gaps shorter than one second from a naturalistic driving study with SAE Level 2 automation

•Adaptive cruise control (ACC) and lane keeping system (LKS) affect driver behaviour.•Changes in the longitudinal control are analysed in logistic regression models.•The analysis is based on naturalistic driving data with ACC and LKS.•Drivers were less likely to speed when ACC and LKS were active.•Drivers were less likely to have a short time gap when ACC and LKS were active.