Study On Delay Considering Movement Behavior Of Vehicle At Signalized Intersection

The present paper which is mainly depends on the Key Project of Chinese National Programs for Fundamental Research and Development(973 Program) “Effectiveness analysis technology of public transport dominant multi-mode transportation network” and National Science and technology support program "Evolution mechanism and control method of urban traffic supply and demand structure” and Liaoning Province education department project “Study on the flow state of the capacity of road network based on city traffic” has researched on the delay model of signalized intersection based on vehicles movement behavior analysis.The delay is defined as additional and unexpected increase traveling time of vehicles which is produced at signalized intersections due to traffic control and other reasons. Delay is the main index to evaluate the service level and operation status at urban signalized intersections. Minimum delay is optimization objective of setting up traffic signal timing at intersection. The delay is also an important parameter for traffic flow modeling. This paper firstly analyses the movement behavior of vehicles. The minimum time headway of straight and turn vehicles can be derived on the premise of safe driving. This paper analyses the starting wastage time and the stopping loss time, and studies the relationship between platoon dispersion and delay. The maximum delay model in short length signalized intersection under saturated traffic flow is established.The research content includes the following parts; the specific contents are as follows:1. Analysis of vehicle operating characteristics at signalized intersectionWhen vehicles pass through the intersection of the signal on the urben road, they often encounter some of the following situations: When the green light is flashing or the yellow light begins to shine in intersection, some vehicles will pass through the intersection, and some vehicles will slow down and stop in stop line. When the red light is on, the vehicle will wait in stop line. If the traffic flow is in a relatively high degree of saturation, in some road(mainly short length road), the vehicle queuing length will be close to and even equal to the length of the road. But it is not possible over the length of the road. When the green light is on again, the vehicles will leave the intersection. When the vehicles start up through the stop line, the flow rate will from zero to reach a stable value, i.e., the saturated flow rate(or the saturated flow). But the leading vehicles cannot reach the saturated flow. Starting process of vehicles that requires extra time and operation time will cause a certain time loss. Before the queuing vehicles reach to stop the line at the next intersection, the space headway of the queuing vehicles will gradually pull apart. This is occurred platoon dispersion phenomenon.This series of vehicles movement behavior produced 4 kinds of traffic phenomena: the phenomenon of traffic flow brake to queue at the intersection with red light on, the phenomenon of the unsaturation traffic flow delay starting from green light on, the phenomenon of vehicles overflowing in short length signalized intersection under saturated traffic flow and the phenomenon of fleet through the intersection occurring platoon dispersion.The 4 kinds of traffic phenomenon have different effects on the delay in the intersection. The starting and braking process of the traffic flow at the intersection will product the starting wastage time and the stopping loss time. The difference of the discrete phenomenon will also have different effects on the delay. The delay caused by vehicle overflow is limited by the length of the road. And the saturation flow rate is one of the important parameters for the calculation of the delay.2. The establishment of delay model according to the vehicle motion characteristics. Four kinds of delay models are established for the traffic phenomena.1) Analyzing for the starting wastage time and the stopping loss time considering release characteristics of the fleet at the signalized intersection.The difference between the time of the traffic flow passing through the stop line in the starting process or in the stopping process and the time of the saturation headway, that is, the starting wastage time and the stopping loss time.Firstly, motion characteristics of the vehicle or the traffic flow at the intersection is analysed. Then, by using the method of mathematical statistics to analyze the data of field survey, the start position of saturated flow rate and the saturation time headway can be determined. Finally, the delay model with the unsaturation flow rate is derived. The starting wastage time and the stopping loss time will have an effect on the whole queuing traffic flows. The delay model of the starting wastage time and the stopping loss time will be established by using queuing theory.2) Analysis of saturation flow rate considering vehicle movement behavior.The saturated time headway is an important parameter to analyze the saturation flow rate, the starting wastage time and the stopping loss time. It is the saturation time headway when traffic flow is in the saturation state. At this time, the time headway of the fleet is smaller. The safe operation of saturated flow is an important guarantee to avoid the occurrence of unexpected delays. Traffic safety is the premise of all traffic behavior and traffic management measures. In this part, the minimum space headway including the straight the left and the right minimum time headway will be derived by using the space headway. With the field observation the theoretical model has been conducted to verify.3) Study on the delay of platoon dispersion by considering coordinated control.When the traffic flow passes through the stop line the space headway of vehicles will increase with the velocity of vehicles increasing. The phenomenon of platoon dispersion will occur in the fleet. And the fleet’s platoon discrete phenomenon also will have an impact on the delay at the next intersection. In this part, the data is used to fit the platoon dispersion behavior of the fleet. And the parameters of the platoon dispersion model of the fleet are modified. Then the influence of the platoon dispersion behavior of the fleet on the downstream intersection delay is discussed under the condition of coordination control.4) Research on the delay model of vehicles in short length signalized intersection.When the traffic flow is in the saturated state, the length of queuing vehicle at the signalized intersection may be close to the length of the road. And the use of the traditional delay model to calculate the delay will appear larger deviation. In this part, the delay model in short length signalized intersection is established based on the restriction of the length of the road.The major innovations of the paper are:1) Based on analysis of the characteristics of single vehicle and traffic flow the traffic flow in the signalized intersection, the first saturation time headway and the specific values are determined by using statistical method. A delay model for the starting wastage time and the stopping loss time in the starting process and the braking process is established.2) With traffic safety, the concept that determined the minimum time headway by using the safety space headway is proposed. The minimum time headway model has been built under safety conditions. The time headway includes the straight time headway, the left turn time headway and the right turn time headway. The model is consistent with measured data.3) With the change of vehicle speed and the differences of driver’s driving behavior, the space headway will gradually increase after the fleet leaving upstream intersection. With the occurrence of the platoon dispersion behavior the fleet is moving to the downstream intersection. The different effects are studied with the different reach of the fleet.4) The phenomenon of overflow will happen in some sections under over saturated. It is named that the vehicles queue back to the upstream intersection. The maximum delay model in short length signalized intersection under saturated traffic flow is established.