Relation Among Average Speed, Flow, and Density and Analogous Relation Between Density and Occupancy

1997 ◽  
Vol 1591 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Michael J. Cassidy ◽  
Benjamin Coifman
Keyword(s):  
Vehicle Speed ◽  
Average Speed ◽  
Loop Detectors ◽  
Speed Flow ◽  
Growing Body ◽  
Analogous Relation

To counter the growing body of literature disputing that average vehicle speed is the ratio of flow to density, the relation is shown to hold as an identity when the variables are defined in the manner described by Edie. In similar fashion, the analogous relation between density and occupancy is shown to be true. These identities are illustrated with data measured by paired loop detectors, which underscores that Edie’s definitions are natural ways to treat the variables. The detector data are further used to show that any disputes surrounding the validity of these identities are largely the result of having defined (i.e., measured) the traffic variables in some other ways.

Lane-by-Lane Analysis Framework for Conducting Highway Capacity Analyses at Freeway Segments

2019 ◽  
Vol 2673 (8) ◽  
pp. 523-535
Author(s):  
Fabio Sasahara ◽  
Lily Elefteriadou ◽  
Shen Dong
Keyword(s):  
Flow Distribution ◽  
Time Of Day ◽  
Heavy Vehicles ◽  
Highway Capacity ◽  
Operational Conditions ◽  
Highway Capacity Manual ◽  
Loop Detectors ◽  
Speed Flow ◽  
Flow Speeds ◽  
The Usa

The Highway Capacity Manual (HCM) methodology for freeway systems yields average speed values for each segment and does not consider lane-by-lane flow and operational conditions. However, flows are not equally distributed between lanes. In congested conditions and particularly when spillback occurs, flows and traffic conditions vary widely. For example, the rightmost lane may be blocked while the leftmost lane is free-flowing. The purpose of this research is to develop a model for estimating lane-by-lane speeds and flows under various freeway designs and demands. Speed and flow data from loop detectors at several locations around the USA were collected, totaling 531,000 observations aggregated in 15-min intervals. The results show that lane flow distribution is highly dependent on the segment total flow, with different patterns for 4-, 6-, and 8-lane segments. The percentage of heavy vehicles, presence of nearby ramps, day of week, and time of day also affect the distribution of flow among freeway lanes. Theoretical lane-by-lane speed-flow curves were developed and the results were compared with field data. Results showed that lane-by-lane speeds can be estimated accurately, as long as inputs for capacity and free-flow speeds can be provided for each lane in the segment.

Research on Speed Monitoring and early Warning Method for Vehicles Based on RFID Sensor Tag

2010 ◽  
Vol 44-47 ◽  
pp. 466-470
Author(s):  
Jiang Yuan ◽  
Kui Yan ◽  
Zi Xue Qiu ◽  
Jian Xin Shao
Keyword(s):  
Real Time ◽  
Early Warning ◽  
Experimental Results ◽  
New Method ◽  
Vehicle Speed ◽  
Control Center ◽  
Average Speed ◽  
Identity Information ◽  
Monitoring And Early Warning

A new method was proposed for vehicle speed monitoring and early warning based on RFID sensor tag technology to realize real-time speed monitoring in high way. The principle of speed monitoring, the hardware and software of RFID sensor tag and reader network using GPRS technology were introduced in detail. Experimental results show that the actual velocity of vehicles can be acquired by on board RFID sensor tag, when the vehicle drives over the limited speed, the system can voice alarm to the driver. The identity information, actual speed and time of vehicle are read wirelessly by readers installed along the roadside, these messages can be upload to control center through GPRS network to monitor vehicle states, such as the position, average speed, the flow of transportation and so on.

Research on Traffic Flow Characteristics of Urban Expressway

2014 ◽  
Vol 587-589 ◽  
pp. 2036-2039 ◽  
Author(s):  
Yue Li ◽  
Hua Pu Lu
Keyword(s):  
Flow Characteristics ◽  
Scientific Basis ◽  
Urban Traffic ◽  
Traffic Density ◽  
Flow Density ◽  
Stream Data ◽  
Loop Detectors ◽  
Urban Expressway ◽  
Speed Flow ◽  
The Relationship

Urban expressways play an important role in urban traffic networks. Different from the highway speed-flow-density relationship, the urban expressway has more complicate characteristics. With the traffic stream data collected from loop detectors on different sites of the expressway in Beijing, traffic parameters of traffic speed, density and volume are analyzed. As the relationship of speed flow and density changes remarkably during different period of time, this paper establish a speed-flow-density model during nighttime and daytime separately. The relationship among traffic density, speed and volume are key-points analyzed. The research can provide data support and scientific basis for the design and planning of urban expressway.

scholarly journals Effects of Visual Active Deceleration Devices on Controlling Vehicle Speeds in a Long Downhill Tunnel of an Expressway

2021 ◽  
Vol 11 (15) ◽  
pp. 6753
Author(s):  
Fu Wang ◽  
Dengjun Gu ◽  
Yuanyuan Li ◽  
Wei Liu ◽  
Guoyun Wang
Keyword(s):  
Traffic Safety ◽  
Vehicle Speed ◽  
Road Tunnel ◽  
Obvious Effect ◽  
Average Speed ◽  
Environment Changes ◽  
Fold Line ◽  
Before And After ◽  
Passing Ability ◽  
Tunnel Entrance

Because the inside of a road tunnel is a closed strip, the driving environment changes suddenly at the tunnel entrance and exit, which is why accidents occur more frequently in tunnels than elsewhere. Based on visual psychology, reverse-perspective-illusion deceleration lines (RPIDLs) and visual-intervention deceleration devices (VIDDs) were designed to control vehicle speeds near the entrance and in the middle of a tunnel, respectively. Then, to assess the speed-controlling performance of the RPIDLs and VIDDs for vehicles in a long downhill tunnel, laser velocimeters were used to measure the vehicle speeds at different observation points in the tunnel before and after implementing the RPIDLs and VIDDs. The results show that the RPIDLs and VIDDs decreased the average vehicle speed and controlled its dispersion effectively. The 60 m RPIDLs improved the traffic safety in the tunnel without lessening the passing ability therein. The slash-line VIDD had no obvious effect on the maximum vehicle speeds in the middle of the tunnel. Both the 90° fold-line VIDD and the four-yellow–four-white VIDD decreased the maximum vehicle speeds significantly. The 60 m RPIDLs and the 90° fold-line VIDD gave the best deceleration effect on vehicles near the entrance and in the middle of the tunnel, respectively, and controlled the average speed and its dispersion effectively.

scholarly journals PENERIMAAN CELAH YANG DITERIMA DAN EFEKTIFITAS ZEBRA CROSS PADA JALAN PROF. A. MAJID IBRAHIM, KOTA SIGLI

2018 ◽  
Vol 1 (2) ◽  
pp. 47-57
Author(s):  
Saiful Saiful ◽  
Sugiarto Sugiarto ◽  
Renni Anggraini
Keyword(s):  
Hypothesis Testing ◽  
Statistical Method ◽  
Road Networks ◽  
Vehicle Speed ◽  
Gap Acceptance ◽  
Average Speed ◽  
Urban Road ◽  
Pedestrian Crossing ◽  
Banda Aceh

Along with urbanism and rapid motorization in the Pidie district leads to increasing private-mode dependency. Increasing number of the vehicle used in urban road networks could affect the pedestrian crossing facilities, especially within the school zone. Therefore, this study aims to evaluate the needs for pedestrian crossing facilities within school zone located at Prof. A. Majid Ibrahim Road in the Pidie District. The gap acceptance approach is used to evaluate accepted and rejected gaps. Furthermore, the effectiveness of the pedestrian crossing (Zebra Cross) regarding whether it is truly appropriate or not then evaluates using the statistical method of hypothesis testing. The analysis result reveals that the higher speed in the traffic, the greater gap required by crosser. The average speed for the traffic direction of Medan - Banda Aceh is about 47,13 km/h; pedestrians require the distribution of gap value of 85% or about 7 m crossing distance is necessary to available. At the location of the zebra cross 1, in the morning and noon observations show the average gap is about 7.71 and 9.18 seconds, respectively. Furthermore,  as for the location of the zebra cross 2, in the morning and noon observations show the average gap is about 8.69 and 10.20 seconds, respectively. Based on the gap distribution, it concluded that the zebra cross facility at Prof. A. Majid Ibrahim Road is still worth using. As for the effectiveness of zebra cross, based on 85% speed at a distance from 50 m and 30 m can be concluded that zebra cross at Prof. A. Majid Ibrahim Road is ineffective. The absence of a decreasing in vehicle speed as it passes through the zebra cross, the velocity of the vehicle at 50 m from the zebra cross ≥ 30 m from the zebra cross. The speed of the vehicle tends to be stable at the time of going through the zebra cross.

scholarly journals Analisis Dampak Lalulintas Exit Tol Jatikarya Terhadap Jalan Transyogi Cibubur Jawa Barat (Tol Cimanggis-Cibitung)

2018 ◽  
Author(s):  
Darmadi Ir
Keyword(s):  
Traffic Management ◽  
Impact Analysis ◽  
Traffic Density ◽  
Vehicle Speed ◽  
Average Speed ◽  
Toll Road ◽  
Traffic Conditions ◽  
Modeling Analysis ◽  
Traffic Impact ◽  
The Impact

Transyogi Road is the main road used by transportation originating from the Depok city, Bogor district, Bekasi city and Bekasi district. The Transyogi Road and the networks connected to it have experienced a significant increase in traffic density each year, this fact is based on the indicator level of the VC ratio on the Transyogi and surrounding road segments which have reached 0.8 at busy times. With the increase in trips generated from Bekasi Regency and an increase in residential density in Depok and Bogor, it has the potential to increase generation and the traffic attraction from and to the area is affecting by the construction of the Cimanggis - Cibitung toll road. This Traffic Impact Analysis aims to predict the impact of the construction of the Cimanggis - Cibitung Toll Road on the Jatikarya exit, and determine the form of improvement needed, harmonize the decisions regarding land use with traffic conditions, the number and location of access, and alternative improvements . This study method uses 4 (four) transportation modeling, analysis of road capacity, vehicle speed .. From the results of this study, it was concluded that before the toll road the Transyogi road had a performance with a V / C ratio of 0.8 and an average speed of 20 km / hour (if do nothing), while after the exit of the jatikarya toll was operated the V / C ratio was 0.7 and the average speed is 23 km / h (do nothing). While the performance of Transyogi road in the design year 2025 without performing geometric improvements (do nothing) has a road performance with a V / C ratio of 0.98 and an average speed of 12-13 km / hr. While if performance changes are made with capacity building traffic management arrangements, predictive traffic conditions in 2025 traffic performance will be obtained with a v / c ratio of an average of 0.7 with an average speed of 26 km / hour (do something).

scholarly journals EVALUATION OF DEVELOPMENT EFFICIENCY OF BRIGJEND SUDIARTO BUSINESS TOWARDS MOSQUITOON ON SIMPANG MODELING

Pondasi ◽  
2020 ◽  
Vol 23 (1) ◽  
pp. 50
Author(s):  
Muhammad Teqi Wijaya ◽  
Kartono Wibowo
Keyword(s):  
Quantitative Method ◽  
Level Of Service ◽  
Vehicle Speed ◽  
Traffic Flows ◽  
Average Speed ◽  
Traffic Jam ◽  
Traffic Delay

ABSTRACTThis research aims to examine the efficiency of Brigjend Soediarto fly over development towards the traffic jam in Pedurungan intersection. The approach conducted in this research is quantitative paradigm, with the quantitative method in the process of analysis. According to the analysis, the recent condition indicates high traffic flows density in each intersection. The level of service (LOS) in Brigjend Soediarto road is 1,421 in the F level. It is predicted that after the development of fly over, the level of service increasse into C with LOS = 0.579. Meanwhile, the LOS in Soekarno-Hatta road is 0.854 with the D level, and increases into B level with LOS = 0.226. While LOS Fatmawati road is 0.856 with the D level and increases into B with LOS=0.284. Before the development, the vehicle speed in Pedurungan intersection was 5.914 km/hour. After the development is is predicted that the vehice speed will be 49.885 km/hour. So that the average speed is 43.97 km/hour. Based on those analysis, the efficiency of the development of Brigjend Soediarto fly over is 76.28%. It can be concluded by the development of Brigjend Soediarto fly over, it is efficiently increasing the flow of traffic in Pedurungan intersection. Keywords : Brigjend Soediarto Fly Over, Pedurungan Intersection, Traffic Delay 

Sign in / Sign up

Export Citation Format

Share Document