Dr Hamid AL- Jameel
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Dr Hamid AL-Jameel 1 Developing a Simulation Model to Evaluate the Capacity of Weaving Sections
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Developing a Simulation Model to Evaluate the Capacity of Weaving Sections. Dr Hamid AL- Jameel. 1.The aims and objectives 2.Definition of a weaving section 3.Limitations of existing methods 4.Data Collection and Analysis 5.Car-following sub-model 6.Gap Acceptance sub-model - PowerPoint PPT Presentation
Transcript of Dr Hamid AL- Jameel
Dr Hamid AL-Jameel
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Developing a Simulation Model to Evaluate the
Capacity of Weaving Sections
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1.The aims and objectives
2.Definition of a weaving section
3.Limitations of existing methods
4.Data Collection and Analysis
5.Car-following sub-model
6.Gap Acceptance sub-model
7.Weaving rules
8.Calibration of the developed model
9.Validation of the developed model
10.The application of the developed model
11.Management scenarios used by the developed model
12.Conclusions and recommendations
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The aims of this research are to build a simulation model capable of representing the factors influencing the behaviour of weaving vehicles and to evaluate the weaving capacity.
The aim of this study
The aim of this study
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1.To determine the factors/variables that affect weaving capacity based on previous
literature research.
2.To build a simulation model that is capable of representing weaving section using
Visual Compact Fortran.
3.To collect data from several weaving sections with different geometric design.
4.To calibrate the system with field data and to validate the model using another set of
field data.
5.To introduce countermeasures to improve the capacity of weaving section such as
selection of the best location for warning signs or guide signs, and applying different
types of management in terms of changing some geometric designs using pavement
markings.
ObjectivesObjectives
Weaving area: the crossing of two or more traffic streams while travelling in the same general direction without the aid of traffic control devices (HCM 2000).
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DefinitionDefinition
Weaving area: the crossing of two or more traffic streams while travelling in the same general direction without the aid of traffic control devices (HCM 2000).
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DefinitionDefinition
On-ramp
Motorway
Off-ramp
Motorway
R-R
M-M
M-R
R-M
W1= R-M or M-R
W2=R-M or M-R
Vw= W1+W2
VR=VW/V
R=W1/Vw
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DefinitionDefinition
Entrance point
Exit point
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Data have been collected from different sites in the UK . More than 50 hours video recording have been gathered from 7 weaving sections. Besides these data, MIDAS data and published data have been used.
Some of these investigated characteristics are:
1. Effective length For weaving length > 300m is 200m. For weaving length < 150m is all actual length. 2. merging points for merging point < 100m is 80%. for diverging point < 100m is 90%.
2. Volume ratio and weaving ration.
3. Upstream characteristics and gap acceptance for the selected samples from these sites.
Data collectionData collection
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A new safety car-following model has been developed and calibrated with field data
Car-followingCar-following
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The developed model for weaving section has been developed as integrated model for different sub-models such as car- following, lane changing, gap acceptance and weaving. then the developed model has been calibrated with field data such as flow and speed taken from the upstream loop detector as input data and comparison with output data from the two down stream loops from both simulated and field data.
Calibration processCalibration process
Upstream loop After merging loop After diverging loop
M60 9034B M60 9030B M60 9026B
190m 200m 90m
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Calibration processCalibration process
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Validation processValidation process
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The applicationThe application
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The applicationThe application
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The applicationThe application
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The applicationThe application
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The applicationThe application
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The developed model has been used to investigate the effect of some characteristics and
new management scenarios on the capacity of weaving sections. These are:
The HGVs have large effect the capacity of weaving sections because the HGVs occupy
large spacing and poor capability in terms of acceleration and deceleration rates.
The PCE (passenger car equivalent) has been found slightly higher than corresponding
values obtained by other studies such as Vermijs and Shuurman (1998).
Different speed limits have been applied using the developed model. The results show that
the speed limit has no noticeable effect to increase the efficiency of operations at weaving
sections.
new management has been applied by shifting diverging vehicles for a specific distance
downstream of the entrance point. This shifting has been applied using longitudinal solid
line of pavement marking to prevent diverging vehicles from changing lane. Different lengths
of this solid line have been applied using the developed model. A 150m was found to be the
optimum value among others.
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A new management has been applied by this developed model after its calibration and validation. This new management can be summarised by changing the weaving section type from ramp weave (Type A) to Type B using just pavement markings. This change could be applied under specific conditions. The results of applying this management show more encouraging outputs in terms of increasing the level of speed and reducing the effect of bottleneck and queue formation for the field case taken from the Northenden Site 1.
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Thank YouThank You
