Research on three-phase traffic flow modeling based on interaction range

2017 ◽  
Vol 31 (35) ◽  
pp. 1750328 ◽  
Author(s):  
Jun-Wei Zeng ◽  
Xu-Gang Yang ◽  
Yong-Sheng Qian ◽  
Xu-Ting Wei

On the basis of the multiple velocity difference effect (MVDE) model and under short-range interaction, a new three-phase traffic flow model (S-MVDE) is proposed through careful consideration of the influence of the relationship between the speeds of the two adjacent cars on the running state of the rear car. The random slowing rule in the MVDE model is modified in order to emphasize the influence of vehicle interaction between two vehicles on the probability of vehicles’ deceleration. A single-lane model which without bottleneck structure under periodic boundary conditions is simulated, and it is proved that the traffic flow simulated by S-MVDE model will generate the synchronous flow of three-phase traffic theory. Under the open boundary, the model is expanded by adding an on-ramp, the congestion pattern caused by the bottleneck is simulated at different main road flow rates and on-ramp flow rates, which is compared with the traffic congestion pattern observed by Kerner et al. and it is found that the results are consistent with the congestion characteristics in the three-phase traffic flow theory.

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Bo Yang ◽  
Yao Wu ◽  
Weihua Zhang

The objective of this study is to analyse the relationship between secondary crash risk and traffic flow states and explore the contributing factors of secondary crashes in different traffic flow states. Crash data and traffic data were collected on the I-880 freeway in California from 2006 to 2011. The traffic flow states are categorised by three-phase traffic theory. The Bayesian conditional logit model has been established to analyse the statistical relationship between the secondary crash probability and various traffic flow states. The results showed that free flow (F) state has the best safety performance of secondary crash and synchronized flow (S) state has the worst safety performance of secondary crashes. The traditional logistic regression model has been used to analyse the contributing factors of secondary crashes in different traffic flow states. The results indicated that the contributing factors in different traffic flow states are significantly different.


2012 ◽  
Vol 23 (09) ◽  
pp. 1250060 ◽  
Author(s):  
YIZHI WANG ◽  
YI ZHANG ◽  
JIANMING HU ◽  
LI LI

One frequently observed congested traffic flow pattern is wide moving jam (WMJ), in which the average vehicle speed is very low and the density is very high. In some recent studies, variable speed limits (VSL) were proposed as effective measures to eliminate or abate the influence of jam waves. However, in most of these studies, the stochastic features of driving behaviors and the resulting uncertainty of traffic flow dynamics were not fully considered. In this paper, we use cellular automaton (CA) model-based simulations to test the performances of different VSL control strategies and apply the three-phase traffic theory to further analyze the obtained results. Based on the simulation results, we got two novel findings. Firstly, we observed seven, instead of the previously assumed six, states of traffic flow in the evolution process of WMJ, when VSL were applied. Secondly and more importantly, we found that inappropriate speed limit may induce new WMJ and exaggerate congestions in two ways: one way corresponds to an F → J transition and the other corresponds to an F → S → J transition. Based on these findings, the appropriate lower bound of VSL was finally discussed in this paper.


Author(s):  
Joshua Stipancic ◽  
Luis Miranda-Moreno ◽  
Nicolas Saunier

Mobility and safety are the two greatest priorities within any transportation system. Ideally, traffic flow enhancement and crash reductions could occur simultaneously, although their relationship is likely complex. The impact of traffic congestion and flow on road safety requires more empirical evidence to determine the direction and magnitude of the relationship. The study of this relationship is an ideal application for instrumented vehicles and surrogate safety measures (SSMs). The purpose of this paper is to correlate quantitative measures of congestion and flow derived from smartphone-collected GPS data with collision frequency and severity at the network scale. GPS travel data were collected in Quebec City, Quebec, Canada, and the sample for this study contained data for more than 4,000 drivers and 20,000 trips. The extracted SSMs, the congestion index (CI), average speed ( V), and the coefficient of variation of speed (CVS) were compared with crash data collected over an 11-year period from 2000 to 2010 with the use of Spearman’s correlation coefficient and pairwise Kolmogorov–Smirnov tests. The correlations with crash frequency were weak to moderate. CI was shown to be positively correlated with crash frequency, and the relationship to crash severity was found to be nonmonotonous. Higher congestion levels were related to crashes with major injuries, whereas low congestion levels were related to crashes with minor injuries and fatalities. Surprisingly, V was found to be negatively correlated with crash frequency and had no conclusive statistical relationship to crash severity. CVS was positively correlated with crash frequency and statistically related to increased crash severity. Future work will focus on the development of a network screening model that incorporates these SSMs.


2014 ◽  
Vol 17 (3) ◽  
pp. 129-139
Author(s):  
Tuan Anh Nguyen ◽  
Zhou Wen-Hui ◽  
Yu Jian-Jun

With the continuous growth of the urban population, traffic congestion has become a major problem in all cities. Congestion charging is in practice an effective tool to solve this problem. In this paper, we use the classical model of Congestion Charging to study the issues of pricingcharges in Ho Chi Minh City. In order to capture the traffic flow, we adopt the Drake speed - density model, which relies on the relationship of speed, density and flow and is further conducted by monitoring the traffic flow. After collecting the base traffic data of Ho Chi Minh City, we analyzed the relationship among speed, density and flow. The result showes that, the model we use performance better in reflecting the actual situation in Ho Chi Minh City than other models. Finally, this paper also numerically shows how much should charge to achieve the expected speed. The corresponding traffic density and flow are given in these examples as well.


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