The impact of guide sign informational density on driver cognitive load: An integrated simulator and real-world driving study

In road sign design, inappropriate layout can easily lead to excessive cognitive load on drivers. This hinders their ability to effectively allocate attention, resulting in missed critical road information and increased accident risks. Through empirical studies on drivers’ visual recognition characteristics and cognitive load, this study investigates the rationality of information volume settings in urban road guide signs. It employed a combination of simulation experiments and real vehicle tests. An information volume calculation model for guide signs was established. The visual recognition simulation experiment was designed to collect data. Real vehicle experiment was conducted to dynamically record drivers’ physiological indicators. A cognitive load assessment model was developed to explore the reasonable range of information density for sequentially signs. From the perspective of ensuring reasonable visual recognition accuracy, the information volume of a single guide sign should be less than 90 bit on arterial roads and below 95 bit on secondary distributor roads. Real vehicle test results indicate that when the information density is below 9.1 bit/s, drivers experience relatively low cognitive load. When the information density exceeds 10.7 bit/s, cognitive load increases significantly. To ensure driving comfort and safety, the information density of signs should not exceed 12.0 bit/s. The information volume on guide sign should be maintained within a reasonable range. The information density of successive signs significantly influences drivers’ cognitive load levels. These findings provide theoretical guidance and practical recommendations for optimizing the information design of urban guide signs and enhancing traffic safety.