A clustering approach to developing car-to-two-wheeler test scenarios for the assessment of Automated Emergency Braking in China using in-depth Chinese crash data.

Two-wheeled vehicles (motorized and non-motorized, referred to as TWs) are an important part of the transport system in China. They also represent an important challenge for road safety, with many TW user fatalities and injuries every year. Recently, active safety systems for cars, such as Automated Emergency Braking (AEB), promise to reduce road traffic fatalities and injuries. For these systems to work effectively, it is necessary to understand and define the complex traffic scenarios to be addressed. The aim of this study is to contribute to the development of test procedures for AEB specifically, drawing on the China In-Depth Accident Study (CIDAS) data from July 2011 to February 2016 to describe typical scenarios for crashes between cars and TWs by means of cluster analysis. In total, 672 car-to-TW crashes were extracted. The data was clustered according to five main crash characteristics: time of crash, view obstruction, pre-crash driving behavior of the car driver and the TW driver, and relative moving direction. The analysis resulted in six car-to-TW crash scenarios typical of China. In three scenarios the car and the TW travel perpendicularly to each other before the crash, in two they travel in the same direction, and in one they travel in opposite directions. Further, each scenario can be described with three characteristics (the road speed limit, the TW's first contact point on the car, and the car's first contact point on the TW) that can be included in an AEB test suite. Some scenarios were similar to those in the Euro New Car Assessment Program (Euro NCAP). For example, in one, a TW moving straight ahead was hit by a car moving perpendicularly, and in the other the car hit a TW traveling in the same direction. Both occurred in daytime, without a visual obstruction. However, in contrast to the Euro NCAP, typical scenarios in China included night-time scenarios, scenarios where the car or the TW was turning, and those in which the TW was hidden from the car by an obstruction. The results contribute to a proposed novel AEB test suite with realistic scenarios specific to China.