按照（   ）分，可将交通冲划分为正向冲突、侧向冲突、超车冲突、追尾冲突等

A．The key survey is a comprehensive survey conducted by selecting a part of the samples among the survey subjects
B．Observation can obtain a lot of real first-hand data, but it takes a lot of manpower, material resources, financial resources and time
C．Observation is a kind of blind passive feeling
D．The meaning of validity and reliability of statistical data is consistent