Speed and safety: evidence from highways in China

The relationship between speed and traffic crashes has been a subject of research interest for many years due to its significance in efficiency and safety of highway operations. The complex and sometimes inconsistent results of these studies come from the diversity of highway design, traffic characteristics and most importantly driver behaviors. This paper presents the results of a project that investigates how operating speed affects highway safety in China. Particularly, this study developed a model to explore the relationship between speed and safety. As highway mileage in China expands quickly with unprecedented investment in roadway construction, safety and efficiency have become top priority. The results of this study indicate not only operating speed but also the magnitude of speed differential between large and small vehicles significantly affects crash occurrences. The results provide much needed information on how to manage speed in order to maximize both safety and traffic flow efficiency in a practical manner.