Analysis traffic safety for highway off-rampbased on visual reaction time on traffic signs

To ensure traffic safety of highway off-ramp area, it should leave enough reaction time for drivers taking corresponding actions after traffic signs. And the recognition time for traffic signs depends on information volume. In this study, traffic sign recognition process in highway off-ramp were analyzed and visual recognition time model was set up. Then, the information volume contained in traffic signs was calculated using the information theory, and the information was divided it into four grades. In order to analyze the recognition time for different information grades, a simulation driving experiment was implemented. 20 participants took part in this experiment and the time for four grades was obtained. An evaluation approached was proposed, which identifies the safety conditions of highway off-ramp into four levels according to the time ranges after recognition. The proposed traffic safety evaluation method may provide a new way to evaluate the safety for highway off-ramp for its intuitive, easy operation and reasonable, especially for setting traffic signs information volume.