scholarly journals The Effect of Posted Speed Limit on the Dispersion of Traffic Flow Speed

2019 ◽  
Vol 11 (13) ◽  
pp. 3594 ◽  
Author(s):  
Chao Gao ◽  
Jinliang Xu ◽  
Qunshan Li ◽  
Jie Yang
Keyword(s):  
Traffic Flow ◽  
Flow Speed ◽  
Traffic Volume ◽  
Free Flow ◽  
Speed Limit ◽  
Flow State ◽  
Speed Limits ◽  
Limit Values ◽  
Average Speed ◽  
The Road

Speed dispersion is an important indicator to portray the quality of traffic flow and is closely related to the road safety operation level. In order to clarify the influence of posted speed limits on the dispersion of traffic flow speed, three sections with speed limits of 80 km/h, 100 km/h and 120 km/h on the same expressway were selected for observation, and traffic volume, speed and other parameters were collected. The characteristic speeds, such as average speed, V15 and V85, were evaluation indicators, where V15 and V85 are the speeds of the 15th and 85th percentiles measured at the feature points of the road when the traffic is in a free-flow state and the weather is good. The relationship between different posted speed limit values and the above indicators was analyzed using the statistical analysis software, SPSS. The results show that the speed limit has a high correlation with the average speed of traffic flow, V15 and V85 in free-flow state, with the coefficient of determination being as high as 0.84, 0.85 and 0.92, respectively. In the restricted flow state, the factors affecting the driver’s driving speed are mainly the decrease in driving freedom caused by the increase of traffic volume rather than the speed limit value. In a free-flow state, when the posted speed limit is increased and the average speed and the V85 also increased by approximately the same magnitude. The posted speed limit values of 80 km/h, 100 km/h and 120 km/h correspond to the 90, 88 and 97 percentile speeds of the traffic flow, respectively. The higher the speed limit is, the larger the speed difference between V15 and V85 becomes. The results of the study are very useful for rationally determining the speed limit scheme under different traffic flows.

scholarly journals Modeling of the Relationship Between Speed Limit and Characteristic Speed of Expressway Traffic Flow

2019 ◽  
Vol 11 (17) ◽  
pp. 4621 ◽  
Author(s):  
Jie Yang ◽  
Jinliang Xu ◽  
Chao Gao ◽  
Guohua Bai ◽  
Linfang Xie ◽  
...  
Keyword(s):  
Traffic Flow ◽  
Highway Safety ◽  
Free Flow ◽  
Speed Limit ◽  
Vehicle Speed ◽  
Flow State ◽  
Speed Limits ◽  
Characteristic Speed ◽  
The Relationship ◽  
Strong Linear Relationship

Understanding the relationship between speed limit and characteristic speed of expressway traffic flow is of great significance for formulating a reasonable speed limit scheme and improving highway safety and transportation efficiency. In this study, the speed data of the same traffic flow passing through speed limits of 80, 100, and 120 km/h were continuously collected through a field test. The 85th, 15th, and 50th percentile speeds were considered the characteristic speed parameters of the traffic flow. A regression analysis was performed to establish a relationship between the characteristic speed parameters of the traffic flow and the speed limit. Under a free-flow state, the characteristic speed exhibited a strong linear relationship with the speed limit, where the variation ranges of the 85th and 50th percentile speeds were approximately consistent with that of the speed limit. However, a slight inconsistency was found for the 15th percentile speed, which was approximately half the speed limit increase; under a non-free-flow state, the correlation between the speed limit and the vehicle speed was no longer significant.

scholarly journals Improving the Level of Service of a Portion of 60-M Ring-Road in Erbil City

2019 ◽  
Vol 3 (1) ◽  
pp. 12-17 ◽  
Author(s):  
Dlzar B. Qadr ◽  
Shorsh A. Mohammed ◽  
Ibrahim A. Hasan ◽  
Rawand F. Mohammed Ali
Keyword(s):  
Traffic Flow ◽  
Urban Area ◽  
Video Camera ◽  
Traffic Volume ◽  
Level Of Service ◽  
Kurdistan Region ◽  
Average Speed ◽  
Ring Road ◽  
The Road ◽  
New City

This study aims to implement the factors that can improve the level of service of 60-M Ring-Road in Erbil, Kurdistan Region of Iraq. These factors are minimizing the traffic volume, providing a higher quality pavement, widening the road carriageway, and constructing bridges. The main objective of this paper is to increase the LOS of a specific road known as 60-m ring road from New City Mall to PAR hospital in Erbil city. For this purpose, the data on speed and traffic flow are collected using video camera to collect data to be reasonably analyzed with respect to the speed of the vehicles and set the LOS for the proposed road. The result shows that average speed in this study is 19 km/h, and this confirms that the LOS in this particular road segment is at F category. In addition, the calculated peak hour factor is 0.97 which is more than a typical value in urban area. Finally, the study revealed that the traffic volume on this specified road is too high.

Numerical Simulation of Traffic Flow in the Tollgate Area with Variable Speed Limits

2011 ◽  
Vol 130-134 ◽  
pp. 3404-3409
Author(s):  
Wen Xing Zhu ◽  
Zhi Ping Jia
Keyword(s):  
Traffic Flow ◽  
Velocity Model ◽  
Flow Speed ◽  
Open Boundary ◽  
Speed Limit ◽  
Variable Speed ◽  
Variable Speed Limit ◽  
Speed Limits ◽  
Optimal Velocity ◽  
Variable Speed Limits

We investigate behaviors of vehicles passing a controlled area with variable speed limits (VSL) before a tollgate. The traffic flow mathematical model is formulated based on optimal velocity model. The typical sketch of tollgate area is plotted and variable speed limit signs are set in the area to control the traffic flow speed for fear of accident and congestion. Simulations are carried out to examine the influence on traffic flow passing the controlled area with different number of the speed limit signs under open boundary condition. The simulations results show that more speed limit signs may reduce the risk of rear-end collision and the occurrence of the congestion in the tollgate area.

scholarly journals ANALISIS KAPASITAS DAN KINERJA LALU LINTAS PADA RUAS JALAN JENDERAL SUDIRMAN JAKARTA

2021 ◽  
Vol 4 (1) ◽  
pp. 95
Author(s):  
Sarah Haryati ◽  
Najid Najid
Keyword(s):  
Flow Speed ◽  
Traffic Volume ◽  
Capital City ◽  
Free Flow ◽  
Degree Of Saturation ◽  
Level Of Service ◽  
Traffic Jam ◽  
Traffic Capacity ◽  
Traffic Behavior

Jakarta as the capital city of Indonesia is the center of economy, culture, and politics. Jenderal Sudirman street always crowded with passing vehicles, traffic snarls up everyday. The causes of these traffic jam is an increase the number of vehicles and cause a change in traffic behavior. Theoretically there is a fudamental relationship between flow, speed, & density, so the purpose of these research are to analyze and evaluate performance of traffic capacity in various conditions based on Manual Kapasitas Jalan Indonesia 1997 and Greenshields model. Conclusion of the analysis are, after compared with traffic volume, capacity and speed based on MKJI are 3.127,6 pcu/hour and 55,7 km/hour, but the capacity of the model are selected because it’s largest, for sudirman – thamrin it’s 8.272,5 pcu/hour, and for thamrin – sudirman it’s 8.067,9 pcu/hour, While the calculation of free flow for sudirman – thamrin it’s 41.2 km/hour the lowest occurs in  evening, and for thamrin – sudirman it’s 43,9 km/hour the lowest occurs in  afternoon. The largest capacity it’s used for the next analysis, the next analysis are calculating degree of saturation and level of service, the result  shows that the roads are at C and D.ABSTRAKJakarta ibu kota negara Indonesia merupakan pusat ekonomi, budaya, dan politik. Sebuah jalan di Jakarta yaitu Jenderal Sudirman selalu dipadati kendaraan. Lalu lintas di Jalan Jenderal Sudirman setiap hari mengalami kemacetan penyebabnya adalah peningkatan jumlah kendaraan di dalam kota dan menyebabkan perubahan perilaku lalu lintas, secara teoritis terdapat hubungan yang mendasar antara arus, kecepatan, dan kepadatan. Tujuan penelitian ini adalah untuk menganalisis, mengevaluasi kinerja dan kapasitas lalu lintas di berbagai macam kondisi, tentu berdasarkan pedoman Manual Kapasitas Jalan Indonesia dan kapasitas model Greenshields. Dari hasil analisis hasil perhitungan kapasitas dan kecepatan arus bebas berdasarkan MKJI sebesar 3.127,6 smp/jam dan 55,7 km/jam setelah dibandingkan dengan volume lalu lintas dipilih kapasitas model yang terbesar yaitu sebesar 8.272,5 smp/jam pada sudirman - thamrin & 8.067,9 smp/jam pada thamrin - sudirman, dan hasil perhitungan kecepatan arus bebas terendah sebesar 41,2 km/jam di sore hari untuk sudirman - thamrin, sebaliknya thamrin - sudirman terendah sebesar 43,9 km/jam di siang hari. Gunakan kapasitas yang terpilih tersebut untuk analisis berikutnya yaitu perhitungan ratio perbandingan arus dan kapasitas (DS) dan tingkat pelayanan yan berada pada tingkat pelayanan huruf C dan D di kedua arahnya.

scholarly journals THE TRAFFIC VOLUME AND LEVEL OF SERVICE (LOS) OF UNIVERSITI PUTRA MALAYSIA (UPM) SERDANG CAMPUS MAIN ACCESS

2019 ◽  
Vol 17 ◽  
Author(s):  
Zakiah Ponrahono ◽  
Noorain Mohd Isa ◽  
Ahmad Zaharin Aris ◽  
Rosta Harun
Keyword(s):  
Traffic Flow ◽  
Traffic Congestion ◽  
Noise Pollution ◽  
Traffic Volume ◽  
Level Of Service ◽  
Idle Mode ◽  
The Road ◽  
Road Capacity ◽  
Motorized Vehicles ◽  
University Setting

The inbound and outbound traffic flow characteristic of a campus is an important physical component of overall university setting. The traffic circulation generated may create indirect effects on the environment such as, disturbance to lecturetime when traffic congestion occurs during peak-hours, loss of natural environment and greenery, degradation of the visual environment by improper or illegal parking, air pollution from motorized vehicles either moving or in idle mode due to traffic congestion, noise pollution, energy consumption, land use arrangement and health effects on the community of Universiti Putra Malaysia (UPM) Serdang. A traffic volume and Level of Service (LOS) study is required to facilitate better accessibility and improves the road capacity within the campus area. The purpose of this paper is to highlight the traffic volume and Level of Service of the main access the UPM Serdang campus. A traffic survey was conducted over three (3) weekdays during an active semester to understand the traffic flow pattern. The findings on traffic flow during peak hours are highlighted. The conclusions of on-campus traffic flow patterns are also drawn.

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 Urban Arterial Road Optimization and Design Combined with HOV Carpooling under Connected Vehicle Environment

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Lina Mao ◽  
Wenquan Li ◽  
Pengsen Hu ◽  
Guiliang Zhou ◽  
Huiting Zhang ◽  
...  
Keyword(s):  
Traffic Congestion ◽  
Negative Impact ◽  
Traffic Volume ◽  
Road Segment ◽  
Connected Vehicle ◽  
Traffic Data ◽  
Average Speed ◽  
The Road ◽  
Arterial Road ◽  
Urban Arterial

The HOV carpooling lane offers a feasible approach to alleviate traffic congestion. The connected vehicle environment is able to provide accurate traffic data, which could optimize the design of HOV carpooling schemes. In this paper, significant tidal traffic flow phenomenon with severe traffic congestion was identified on North Beijing road (bidirectional four-lane) and South Huaihai road (bidirectional six-lane) in Huai’an, Jiangsu Province. The historical traffic data of the road segments were collected through the connected vehicle environment facilities. The purpose of this study is to investigate the effect of adopting two HOV schemes (regular HOV scheme and reversible HOV carpooling scheme) on the urban arterial road under connected vehicle environment. VISSIM was used to simulate the proposed two HOV carpooling schemes at the mentioned road segment. The simulation results showed that the reversible HOV carpooling scheme could not only mitigate the traffic congestion caused by traffic tidal phenomenon but also improve the average speed and traffic volume of the urban arterial road segment, while the regular HOV scheme may exert a negative impact on the average speed and traffic volume on the urban arterial road segment.

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 Estimating Free-flow Speed from Posted Speed Limit Signs

2011 ◽  
Vol 16 ◽  
pp. 306-316 ◽  
Author(s):  
Matthew D. Deardoff ◽  
Brady N. Wiesner ◽  
Joseph Fazio
Keyword(s):  
Flow Speed ◽  
Free Flow ◽  
Speed Limit ◽  
Free Flow Speed
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