关键词: 交通流系统, 复杂性测度, 联合熵, C0复杂度, 快速傅里叶变换

Abstract: In order to quantitatively describe complexity of traffic flow system，adopt union entropy and C0 complexity to analyze traffic flow series.How many non-linear ingredients in system is reflected by calculating union entropy of primitive series and surrogate series，how many non-regular ingredients in system is reflected by calculating C0 complexity.The union entropy and C0 complexity of periodic sequence，Logistic sequence，Henon sequence，random sequence and real traffic flow sequences of five different time intervals have been calculated.The results show that different sequence has different union entropy and C0 complexity and the computation demands sample few，traffic flow system is a chaotic system which situated between order and disorder，rule and non-rule，different traffic flow has different union entropy and the C0 complexity，the union entropy and the C0 complexity are suitable for quantitatively describing the complexity of traffic flow system.

Key words: traffic flow system, complex measure, union entropy, C0 complexity, Fast Fourier Transform