scholarly journals The impact of the average traffic flow speed on occurrence risk of road crash

2019 ◽  
Vol 65 (2) ◽  
pp. 29-36
Author(s):  
Dalibor Pešić ◽  
Boris Antić ◽  
Emir Smailovic ◽  
Bojana Todosijević
Keyword(s):  
Traffic Flow ◽  
Flow Characteristics ◽  
Flow Speed ◽  
Flow Density ◽  
Average Speed ◽  
Flow Parameters ◽  
Flow Speeds ◽  
Road Crash ◽  
The Subject ◽  
The Impact

Traffic flow characteristics have a significant impact on occurrence risk of road crash. The most important characteristics of the traffic flow, the impact of which is the subject of numerous studies, are the traffc flow, density, average traffic flow speed, dispersion of traffic flow speeds, as well as the contents of vehicle in traffic flow. These characteristics are in strong correlation between each other, so changes in one parameter conditional make change of other parameters. Research shows that speed-related traffic flow parameters have a significant impact on occurrence risk of road crash. Therefore, in this study an analysis of the impact of the change in the average speed of the traffic flow on the risk of an accident occurred. The research includes a section of the single carriageway from Preljina to Ljig. After the construction of the highway in the stated section of the signle carriageway, a change in the characteristics of the traffic flow occurred, with this study examining the impact of changing the average speed of the traffic flow to the occurrence risk of road crash. The connection between the speed of traffic flow and the risk of accidents has been confirmed in this study, so with the increase in average speed the risk of accidents increases.

scholarly journals Research of time headways at roundabout approaches

2021 ◽  
Vol 67 (3) ◽  
pp. 23-28
Author(s):  
Dunja Radović ◽  
Vuk Bogdanović
Keyword(s):  
Traffic Flow ◽  
Flow Characteristics ◽  
Driver Behaviour ◽  
The Road ◽  
Traffic Conditions ◽  
Flow Parameters ◽  
Standard Procedures ◽  
Capacity Calculation ◽  
The Impact

It is known that traffic flow characteristics have significant influence at the capacity of all functional segments of the road and street network. One of the most important traffic flow parameters which affect the capacity of roundabouts is follow-up headway at minor approaches of roundabouts. This traffic flow parameter, like the most others, depends on driver behaviour, i.e. local traffic conditions. This paper presents the research results related to follow-up headway at three roundabouts obtained by the photographic method. This data collection method is chosen because its application completely eliminates the impact of research at behaviour of traffic participants. After the research, a representative sample is formed and its processing and analysis led to conclusions about the value of follow-up headway at roundabouts which can be applied in standard procedures for capacity calculation at roundabouts in midsize cities of our region.

scholarly journals Influence of Large Vehicles on the Speed of Expressway Traffic Flow

2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
Chao Gao ◽  
Jinliang Xu ◽  
Xingli Jia ◽  
Yaping Dong ◽  
Han Ru
Keyword(s):  
Traffic Flow ◽  
Large Scale ◽  
Flow Speed ◽  
Flow Data ◽  
Passenger Cars ◽  
Mixing Rate ◽  
Data Set ◽  
Average Speed ◽  
Rate Analysis ◽  
The Impact

Large vehicles impact the quality of traffic flow. To predict the impact of large-scale vehicles on the average speed of traffic flow, vehicle speeds under different vehicle mixing rates were collected through field observations. A laser roadside traffic survey instrument with automatic vehicle type identification functionality was used to collect cross section traffic flow data. The v/C ratio, large vehicle mixing rate, and average speed of traffic were calculated for each data set. A total of 158 traffic flow data sets were captured and divided into three groups according to the v/C ratio of the expressway. The v/C ratio ranges of the three groups are v/C≤0.35, 0.35<v/C≤0.55, and 0.55<v/C≤0.90. SPSS software was used to analyze the correlation between the vehicle mixing rate and the average speed under different traffic flow conditions, and a model was determined between the average speed of the vehicle flow and the large vehicle mixing rate. Analysis of the results with SPSS revealed a negative logarithmic linear relationship between the average traffic speed and the mixing rate of large vehicles. The results could also be applied to passenger cars. The models are considered as corrections of the average speed of the traffic flow after the mixing of large vehicles. When the mixing rate of large vehicles is close to zero, the forecast value of the model is the average speed of passenger cars. Furthermore, as the traffic volume of the road section increased, the influence of the mixing rate on traffic flow speed became more obvious. The adaptability of the proposed prediction model of the expressway mixing rate was verified by evaluating model predictions against actual measurements.

scholarly journals Research on the impact of ship traffic flow on the restricted channel segment of the middle Yangtze River based on traffic wave theory

2021 ◽  
Vol 3 (8) ◽  
Author(s):  
Ting Liu ◽  
Gabriel Lodewijks
Keyword(s):  
Traffic Flow ◽  
Flow Rate ◽  
Flow Simulation ◽  
Wave Theory ◽  
Flow Density ◽  
List Type ◽  
Ship Traffic ◽  
Traffic Wave ◽  
The Impact ◽  
Channel Segment

Abstract Abstract On the basis of the influence of dry season on ship traffic flow, the gathering and dissipating process of ship traffic flow was researched with Greenshields linear flow—density relationship model, the intrinsic relationship between the ship traffic congestion state and traffic wave in the unclosed restricted channel segment was emphatically explored when the ship traffic flow in a tributary channel inflows, and the influence law of multiple traffic waves on the ship traffic flow characteristics in unclosed restricted segment is revealed. On this basis, the expressions of traffic wave speed and direction, dissipation time of queued ships and the number of ships affected were provided, and combined with Monte Carlo method, the ship traffic flow simulation model in the restricted channel segment was built. The simulation results show that in closed restricted channel segment the dissipation time of ships queued is mainly related to the ship traffic flow rate of segments A and C, and the total number of ships affected to the ship traffic flow rate of segment A. And in unclosed restricted channel segment, the dissipation time and the total number of ships affected are also determined by the meeting time of the traffic waves in addition to the ship traffic flow rate of segments. The research results can provide the theoretical support for further studying the ship traffic flow in unclosed restricted channel segment with multiple tributaries Article Highlights The inflow of tributaries' ship traffic flows has an obvious impact on the traffic conditions in the unenclosed restricted channel segment. The interaction and influence between multiple ship traffic waves and the mechanism of generating new traffic waves are explained. The expression of both dissipation time of queued ships and the total number of ships affected in the closed and unclosed restricted channel segment are given.

scholarly journals Developing a New Spatial Unit for Macroscopic Safety Evaluation Based on Traffic Density Homogeneity

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Chen Wang ◽  
Lin Liu ◽  
Chengcheng Xu
Keyword(s):  
Traffic Flow ◽  
Traffic Control ◽  
Flow Characteristics ◽  
Traffic Density ◽  
Minimization Method ◽  
Spatial Unit ◽  
Flow Parameters ◽  
Safety Knowledge ◽  
Traffic Operation ◽  
Crash Modeling

Macrolevel crash modeling has been extensively applied to investigate the safety effects of demographic, socioeconomic, and land use factors, in order to add safety knowledge into traffic planning and policy-making. In recent years, with the increasing attention to regional traffic management and control, the safety effects of macrolevel traffic flow parameters may also be of interest, in order to provide useful safety knowledge for regional traffic operation. In this paper, a new spatial unit was developed using a recursive half-cut partitioning procedure based on a normalized cut (NC) minimization method and traffic density homogeneity. Two Bayesian lognormal models with different conditional autoregressive (CAR) priors were applied to examine the safety effects of traffic flow characteristics at the NC level. It was found that safety effects of traffic flow exist at such macrolevel, indicating the necessity of considering safety for regional traffic control and management. Furthermore, traffic flow effects were also examined for another two spatial units: Traffic Analysis Zone (TAZ) and Census Tract (CT). It was found that ecological fallacy and atomic fallacy could exist without considering traffic flow parameters at those planning-based levels. In general, safety needs to be considered for regional traffic operation and the effects of traffic flow need to be considered for spatial crash modeling at various spatial levels.

Impact of Rainfall Condition on Traffic Flow and Speed: A Case Study in Johor and Terengganu

2014 ◽  
Vol 70 (4) ◽  
Author(s):  
Nordiana Mashros ◽  
Johnnie Ben- Edigbe ◽  
Sitti Asmah Hassan ◽  
Norhidayah Abdul Hassan ◽  
Nor Zurairahetty Mohd Yunus
Keyword(s):  
Traffic Flow ◽  
Monsoon Season ◽  
Flow Speed ◽  
Free Flow ◽  
Road User ◽  
Traffic Data ◽  
Average Volume ◽  
Rainfall Condition ◽  
Free Flow Speed ◽  
The Impact

This paper explores the impact of various rainfall conditions on traffic flow and speed at selected location in Terengganu and Johor using data collected on two-lane highway. The study aims to quantify the effect of rainfall on average volume, capacity, mean speed, free-flow speed and speed at capacity. This study is important to come out with recommendation for managing traffic under rainfall condition. Traffic data were generated using automatic traffic counters for about three months during the monsoon season. Rainfall data were obtained from nearest surface rain gauge station. Detailed vehicular information logged by the counters were retrieved and processed into dry and various rainfall conditions. Only daylight traffic data have been used in this paper. The effect of rain on traffic flow and speed for each condition were then analysed separately and compared. The results indicated that average volumes shows no pronounce effect under rainfall condition compared to those under dry condition. Other parameters, however, show a decrease under rainfall condition. Capacity dropped by 2-32%, mean speed, free-flow speed and speed at capacity reduced by 3-14%, 1-14% and 3-17%, respectively. The paper recommends that findings from the study can be incorporated with variable message sign, local radio and television, and variable speed limit sign which should help traffic management to provide safer and more proactive driving experiences to the road user. The paper concluded that rainfall irrespective of their intensities have impact on traffic flow and speed except average volume.

scholarly journals The impact of heavy vehicle’s composition to traffic performance of Jakarta Intra Urban Toll Road (JIUT) in macroscopic level

2019 ◽  
Vol 276 ◽  
pp. 03018
Author(s):  
Nahry Yusuf ◽  
Ismi Dilianda Wulandari
Keyword(s):  
Traffic Flow ◽  
Exponential Model ◽  
Flow Speed ◽  
Heavy Vehicles ◽  
Flow Models ◽  
Toll Road ◽  
Traffic Performance ◽  
Traffic Flow Models ◽  
The One ◽  
The Impact

Freight vehicle access restriction policy in 2011 has had an impact on the performance of Jakarta Intra Urban Toll way (JIUT) system. The statutory segment (Cawang-Tomang) of this toll road system seems to have better performance, but not for the advisory segment (Cawang -Ancol). Basically, heavy vehicles (HV) shift their routes to the advisory segment to avoid the statutory segment at which they are prohibited to access from 05.00 a.m. to 10.00 p.m.. This study aims to investigate the impact of the HV composition on the traffic performance of the advisory segment of JIUT. Data were obtained from 48 hours of traffic recording at a part of Cawang-Ancol segment. It was found that the Underwood Model (exponential model) can represent the relationship between the three main parameters of traffic flow on the advisory segment, i.e. volume, speed, and density. Based on the developed traffic flow models which are classified on the HV composition, it is shown that the free flow speed (uf) for HV composition < 6% (i.e. 144.91 km/h) is higher 35.41% than the one of HV > 6% (i.e. 107.02 km/h). The actual road capacity (qm) in HV composition < 6% (i.e. 4442 pcu/hour) also higher 12.83% than the one of HV > 6% (i.e. 3937 pcu/hour). The results will benefit to the transport authority to justify the truck access restriction implementation.

Chaos in a Discrete Dynamic Model of Traffic Flow

2007 ◽  
Author(s):  
Meng Xu ◽  
Ziyou Gao
Keyword(s):  
Traffic Flow ◽  
Dynamic Models ◽  
Chaotic Behavior ◽  
Flow Speed ◽  
Free Flow ◽  
Flow Density ◽  
Fundamental Diagram ◽  
Discrete Dynamic ◽  
Curve Model ◽  
Two Parameters

This paper aims to discuss unstable traffic flow and to identify if chaotic phenomena exist in a traffic flow dynamic system. Two discrete dynamic models are proposed, which are derived from the flow-density-speed fundamental diagram and Del Castillo and Benitez’s exponential curve model and maximum sensitivity curve model. Both the models have two parameters, which are the ratio of free flow and spacing average speed and the ratio of the absolute value of kinematic wave speed at jam density and free flow speed. Chaos is found in the two models when the two values increase separately. The Liapunov exponents were used to examine the characters of the chaotic behavior in the two models. These results are illustrated by numerical examples.

scholarly journals Data-driven profiling of traffic flow with varying road conditions

2019 ◽  
pp. 149-157 ◽  
Author(s):  
O K Golovnin
Keyword(s):  
Traffic Flow ◽  
Road Traffic ◽  
Flow Characteristics ◽  
Weather Conditions ◽  
Flow Speed ◽  
Data Driven ◽  
The Road ◽  
Data Driven Approach ◽  
Traffic Flow Characteristics ◽  
The City

The article describes the road, institutional and weather conditions that affect the traffic flow. I proposed a method for traffic flow profiling using a data-driven approach. The method operates with macroscopic traffic flow characteristics and detailed data of road conditions. The article presents the results of traffic flow speed and intensity profiling taking into account weather conditions. The study used road traffic and conditions data for the city of Aarhus, Denmark. The results showed that the method is effective for traffic flow forecasting due to varying road conditions.

Sign in / Sign up

Export Citation Format

Share Document