scholarly journals Impacts of Autonomous Vehicles on Traffic Flow Characteristics under Mixed Traffic Environment: Future Perspectives

2021 ◽  
Vol 13 (19) ◽  
pp. 11052
Author(s):  
Mohammed Al-Turki ◽  
Nedal T. Ratrout ◽  
Syed Masiur Rahman ◽  
Imran Reza

Vehicle automation and communication technologies are considered promising approaches to improve operational driving behavior. The expected gradual implementation of autonomous vehicles (AVs) shortly will cause unique impacts on the traffic flow characteristics. This paper focuses on reviewing the expected impacts under a mixed traffic environment of AVs and regular vehicles (RVs) considering different AV characteristics. The paper includes a policy implication discussion for possible actual future practice and research interests. The AV implementation has positive impacts on the traffic flow, such as improved traffic capacity and stability. However, the impact depends on the factors including penetration rate of the AVs, characteristics, and operational settings of the AVs, traffic volume level, and human driving behavior. The critical penetration rate, which has a high potential to improve traffic characteristics, was higher than 40%. AV’s intelligent control of operational driving is a function of its operational settings, mainly car-following modeling. Different adjustments of these settings may improve some traffic flow parameters and may deteriorate others. The position and distribution of AVs and the type of their leading or following vehicles may play a role in maximizing their impacts.

2021 ◽  
Vol 9 (4) ◽  
pp. 378
Author(s):  
Jong Kwan Kim

As high vessel traffic in fairways is likely to cause frequent marine accidents, understanding vessel traffic flow characteristics is necessary to prevent marine accidents in fairways. Therefore, this study conducted semi-continuous spatial statistical analysis tests (the normal distribution test, kurtosis test and skewness test) to understand vessel traffic flow characteristics. First, a vessel traffic survey was conducted in a designated area (Busan North Port) for seven days. The data were collected using an automatic identification system and subsequently converted using semi-continuous processing methods. Thereafter, the converted data were used to conduct three methods of spatial statistical analysis. The analysis results revealed the vessel traffic distribution and its characteristics, such as the degree of use and lateral positioning on the fairway based on the size of the vessel. In addition, the generalization of the results of this study along with that of further studies will aid in deriving the traffic characteristics of vessels on the fairway. Moreover, these characteristics will reduce maritime accidents on the fairway, in addition to establishing the foundation for research on autonomous ships.


2008 ◽  
Vol 19 (11) ◽  
pp. 1705-1715 ◽  
Author(s):  
WEI-WEI ZHANG ◽  
RUI JIANG ◽  
YAO-MING YUAN ◽  
QING-SONG WU

This paper investigates traffic dynamics of two-lane mixed traffic flow system composed of cars and buses, which are characterized by different lengths and different maximum velocities. Four lane changing regulations are studied, which reveals effect of lane changing ban, symmetric and asymmetric lane changing rules on traffic flow characteristics (flow rate, carry capability, lane changing frequency, and lane usage). We expect that our results could be useful for traffic management.


2016 ◽  
Vol 78 (7-2) ◽  
Author(s):  
Nurul ‘Azizah Mukhlas ◽  
Nordiana Mashros ◽  
Othman Che Puan ◽  
Sitti Asmah Hassan ◽  
Norhidayah Abdul Hassan ◽  
...  

Understanding traffic behavior for obtaining a smooth, safe and economical traffic operation requires a thorough knowledge of traffic flow parameters and their mutual relationships.Eventhough adverse weather can reduce traffic efficiencies, there are still questions to answer regarding the relationship between weather conditions and traffic flow at night. This paper presents an investigation of the rainfall effects to the traffic flow characteristics on atwo-lane rural highway during night time. The traffic data and corresponding rainfall data for uninterrupted road segment of Federal route 3 at Dungun, Terengganu were collected under road lighting condition during the north-east monsoon season. The effect of good weather condition, light rain, moderate rain and heavy rain conditions on speed, flow and density were quantified and compared. Results from the analysis indicate that mean speed, mean flow and mean density are reduced under various rainfall conditions. In general, the impact of good weather and various rainfall conditions on Greenshield’s fundamental traffic flow relationship have weak correlations except for the relationship between flow and density. The important points in the fundamental diagram derived from flow-density relationships indicated that critical density, maximum flow, critical speed, jam density and free flow speed of roadway all decrease as rainfall intensity increases. It can be concluded that traffic flow characteristics of two-lane rural highway in Terengganu are affected by rainfall conditions.


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