Abstract: With the rapid development of vehicle safety driving assistant technique, drivers need to operate other non-driving tasks during the driving period. This may cause increase in the driver's workload. Evaluating the workload by monitoring the driver's physical and psychological signals is one of the basic research methods. The nighttime driving behavior in the driving simulator was studied. Four types of driving experiments, single driving task experiments at day and night, master-slave driving task experiments at day and night, were carried out. On the basis of physiological data and mental workload subject evaluation, the changes of the physical parameters were calculated and analyzed using statistical method. The results show that, compared to daytime driving, the nighttime driving mental workload of the driver is much higher. In the process of master-slave nighttime driving experiment, driver subjective pressure increases significantly, and it is in proportion to the difficulty of the experiment task. ECG and EEG physiological index indicators show that the significant difference and respiratory frequency are different. At the same time, respiratory rate and galvanic skin index change are not obvious. The experimental results can be used in the nighttime road traffic safety evaluation.

Key words: transportation engineering, traffic safety, mental load, physiological characteristics, driving behavior