Analysis of the Evolution Characteristics of Urban Expressway Traffic Oscillations
In order to extract the oscillations data more accurately,the evolution characteristics of traffic oscillations are further explored.First,the growth characteristics of the oscillation are an-alyzed by fitting the speed standard deviation of the oscillating vehicle using a single exponential decay function.Secondly,the short-term Fourier transform is used to extract the change of fre-quency intensity to track the acceleration and deceleration change points of the oscillation head car and the deceleration stage,so as to explore the propagation mechanism of the oscillation.The a-nalysis results show that the standard deviation of the vehicle's speed increases along the concave convoy during the oscillation.The initial stage of the oscillation shows the forerunner stage,this stage of the speed change is slow,and as the speed fluctuation increases,the oscillation growth is spread upstream.Affected by the randomness and instability of vehicles in the interweaving area,the oscillations in different lanes of the main line vary in duration,amplitude and intensity of the deceleration phase due to different vehicle behaviors.
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万方数据
