Safety Analysis on Road Sight Distance

The drivers are supposed to have sufficient distance in order to watch for the changes of the surroundings before cars such as traffic conditions, highway alignments, scenery design and so on, and to take the corresponding actions to ensure driving safely. Based on the principle of the vertical curve design, this paper discusses the safe driving conditions on highways and obtains the relationship between the design length of vertical curve, stopping sight distance and algebra difference of grades. Combined with safety evaluation for one expressway, this paper proposes some reasonable recommendations for black spot treatment.