Interactive traffic impact assessment study for Kuantan

Transcription

[Home] [Session index] [Author index] [Presenter index]
23rd ARRB Conference – Research Partnering with Practitioners, Adelaide Australia, 2008
INTERACTIVE TRAFFIC IMPACT ASSESSMENT STUDY
FOR KUANTAN
Adnan ZULKIPLE, Universiti Malaysia Pahang, Malaysia
Riza Atiq Abdullah O.K. RAHMAT, Universiti Kebangsaan Malaysia,
Malaysia
Amiruddin ISMAIL, Universiti Kebangsaan Malaysia, Malaysia
Azlina ISMAIL, Universiti Malaysia Pahang, Malaysia
ABSTRACT
Issues of maintaining the transportation system that can cope with the land development has
been the main challenge to Local Government Authorities in Malaysia. Realizing this fact, traffic
engineers and planners in the country are struggling to come up with the so called interactive
traffic impact assessment models or techniques which are conveniently associated with the
Geographical Information System (GIS) as the most popular supporting tool for providing data
bases and displaying results of the analysis. However, the application of GIS is not as straight
forward as in most developed countries since the digitalization of the base map and compilation
of the demographic information for the country by a centralised Government Agency are yet to
be completed and handily available for the public use. Interim measures to overcome the
shortcomings of a complete GIS package have to be sought in keeping up with the needs to
develop the interactive traffic analysis and management tools for the Local Authorities. This
paper is proposing a procedure to conduct an interactive traffic impact assessment for District of
Kuantan with aim to simply the route for future integration with the national GIS framework.
INTRODUCTION
Kuantan is the state capital of Pahang, the largest state in Peninsular Malaysia. It is situated
near Kuantan River mouth and facing the South China Sea. If measuring the distance along the
east coast of Peninsular Malaysia, it is located roughly halfway between Singapore and Kota
Bharu. With over 500,000 people Kuantan is the largest city on the Malaysian east coast
(Kuantan 2006).
Kota Bahru
West Malaysia
Pahang
Kuala
Lumpur
Sumatra
Island
Brunei
Kuantan
East Malaysia
Singapore
Borneo
Figure 1: Geographical location of the study area – Kuantan Town
Kuantan is said to have been established since the 1850s. In its early days it is known as
Kampung Teruntum and is situated around the mouth of Sungai Teruntum which is in front of
the current general hospital. Primary economic activities had been fishing and small
© ARRB Group Ltd and Authors 2008
1
businesses. Towards the late 19th century, settlement of Chinese miners and traders saw the
early establishment of township in Kuantan and also nearby tin mines such as Gambang and
Sungai Lembing. Since the shifting of the administrative and commercial centre of Pahang to
Kuantan in 1955, Kuantan is known as a tropical getaway with tourism as one of its major
economic activities. Trade and commerce largely supports the economy of the town with timber
and fishing industries also play vital roles in the local economy. Kuantan is also blessed by a
strong presence of petrochemical industries, located about 25 km to the north of the town
centre. National Physical Plan 2005 has also identified Kuantan as the future growth centre hub
of trades, offices, transportation and tourism in the east coast of Peninsular Malaysia.
Kuantan is connected to Kuala Lumpur via the East Coast Expressway and Federal Highway
Route 2. The East Coast Expressway is not only linking major towns within the state but also
will eventually link Kuantan to other state capitals in the east coast of Peninsular Malaysia. Long
distance travelers however still prefer the old trunk road called Federal Highway Route 2 which
at present provides the essential link to other important east coast towns in the absent of the full
package of the East Coast Expressway. With total length of approximately 176 km within the
State of Pahang, the federal route is easily the most preferred route by both the locals and the
long distance travelers. At national level it provides the link from Kuantan Port to Kuala Lumpur
(the National Capital) and Port Klang (the National Port located about 300 km in the west coast
of Peninsular Malaysia). Figure 2 shows the relative location of the East Coast Expressway and
Federal Highway Route 2 serving Kuantan.
ay
ressw
t Exp
Coas
East Completed
To
Kuala
Lumpur
East Coast Expressway
Under Construction
Kuantan
Interchange
To Major
Town in
The East
Cost
Port of
Kuantan
Gambang
Interchange
2
oute
ay R
ighw
ral H
Fede
Gambang Town
Zone
Kuantan Town
Zone
Figure 2: Relative location of the East Coast Expressway and Federal Route 2
The affected Federal Highway Route 2 that becomes the subject of the study is known as
Kuantan - Gambang Road that link Kuantan Town to Gambang Town and forms the backbone
of Kuantan road network. At present it is an urban arterial of dual 2-lane carriageway similar to
the East Coast Expressway in number of lane but a rank lower in the hierarchy of roads in
Malaysia. With the operation of the main route, the East Coast Expressway, long distance
travellers are supposed to deviate away from using the route. However, there is an unbalanced
consideration for through and local traffic since the road continue to cater as the main trunk
road for through traffic despite its new role to cater for local and generated traffic demand from
new developments along the federal route as shown below.
2
12 km
To/from
Kuantan
&
Terengganu
TUDM
(Air force &
Airport)
Taman Seri Mahkota Aman
Taman Seri Mahkota
Taman Seroku
Pusat Sembelih
MEC Industrial
area 1
Kg Mahkota
Pusat Serenti
University
Malaysia
Pahang
Kg Seri Fajar
MEC Industrial area 2
Gambang Perdana
6 km
bridge
Toll Expressway
Schools zone
Interchange
Legend:
Dual 2-lane carriageway
Major routes
Minor roads
Ingress and egress
(with u-turns for right turning)
Signalised
Intersection
Jaya Gading
Industrial area
Gambang
Transport
Terminal
Taman Seri Mahkota
Federal Route 2
Signalised
Intersection
To/from
Town
Center
Figure 3: Illustration of developments along Kuantan – Gambang Road
OBJECTIVE OF THE PAPER
This paper will emphasize on the issues of implementing the isolated traffic impact assessment
works as per the current practice, explain about the effort to produce a coordinated traffic
impact assessment within a study area and outline of the idea of initiating an interactive traffic
impact assessment system for the town.
GIS for the national road and highway networks in Malaysia have been prepared for application.
Useful data and information such as major link characteristics and traffic volume data might be
available at input level when conducting local road network study such as traffic impact
assessment of a development site. Coordinated effort on converting the results of these studies
into GIS format and export the output to the national/regional GIS web portal will induce a
sustainable practice in the long run as explain below.
REVIEW OF THE PRACTICE OF TRAFFIC IMPACT STUDY IN
MALAYSIA
Traffic impact assessment (TIA) study has been practiced in Malaysia by the local authority as
part of the submission for obtaining the Development Order of a new development since the
early 90’s although it has not been made mandatory by the Government. It has been treated as
one of the essential study elements during the planning and design stage that the developer
needs to comply. However, in most cases, it is required to be carried out in full accordance with
the prevailing best practice, in particular in the area under the jurisdiction of the municipal
council where the project is situated. The developer has to appoint a reputable traffic and
transportation consultant to undertake the study, which include among others the assessment of
the existing and future transportation system with and without the proposed development.
Draft TIA Guidelines (2005) by Road Engineering Association Malaysia (REAM) proposed that a
set of standard criteria and trigger levels to conduct the TIA study be adopted by the authorities
as follows:
•
Additional of 150 vehicle per hour is added from the new development to the road
network during the peak hours.
•
Additional 200 vehicle per hour is added from the new development to the road
network during the off peak hours.
•
The scale of the residential use of the new development is more than 200 dwelling
units.
3
•
The scale of the commercial use of the new development is more than 4000 square
meter.
All the four criteria must be tested, and if any of the criteria reaches the trigger level, then a TIA
study shall be required. However, in specific cases TIA shall be required even if the added trip
generation may be lesser than the trigger levels.
The main goal of the current traffic impact assessment approach is to obtain the approval of the
authority on the proposed traffic mitigation and management measures as to counter the impact
of the proposed development to the prevailing transportation system. According to Zulkiple, et.
al. (2005), the step for obtaining the approval commencing with the appointment of the traffic
impact assessment consultant by the developer and ending with the approval of the approving
authority of the traffic impact assessment study proposals. Outcomes of the TIA study are
supposed to be implemented by the developer with the supervision of the authority. The
developer has no problem to comply with any traffic mitigation plans proposed inside the
compound of the development area since this will help in the sale of the proposed development
units. However, the construction of the access road and the intersection with the main road is
normally limited to priority or signalized intersection that is low cost in nature and can sustain
short to moderate term traffic demand. It is very rare that the access road and the intersection
can sustain long term traffic demand since along the way, other developers might just request to
obtain access to the same intersection via the same access road and the service life of the
access road and the intersection become shorter. The problem is exaggerated by passing
through traffic from new development outside the area of influence of the proposed
development which is not accounted for during the TIA study process. As it is happening, the
traffic congestion problem become complex and simple solution such as readjusting the traffic
signal timing and widening of the intersection are not effective anymore. A more costly solution
such as constructing an interchange or constructing additional lane are more effective but is yet
to be the best solution. The best solution would be the implementation of a comprehensive
public transport system that require a long term planning right from the inception of an isolated
development within the town since in the future, the developers are not around and they are
also not liable anymore to contribute in any form for the upgrading of the proposed
infrastructure.
At present, traffic impact assessment procedure in the country is not well established so that the
approach to the study is not uniform among the traffic consultants even though for studies
conducted within the same study area. Often, the study is tailored to suit the development
needs rather than in the first place to ensure the compliance of the proposed development to
the prevailing traffic management and transportation system of the study area as specified in
the transportation master plan.
The lack of a standardized procedure to conduct traffic impact assessment, contributes to the
deterioration of prevailing transportation system and the inefficiency of the transportation master
plan. Moreover, the proposed traffic mitigation measures of certain developments might not be
streamlined with other developments due to lack of systematic coordination by the governing
authority despite its spatial homogeneity such as its relative location. Thus, the final destination
of having transportation system that contribute to energy-cost-time savings and reduction of the
green effect will never be a reality.
Under a working group committee set up by REAM to produce guidelines for traffic safety and
traffic congestion measures, a draft national traffic impact assessment guideline was prepared
as shown in figure 2. The draft guidelines which adopt similar approach as of the prevailing
traffic impact assessment procedures will ensure standard practices by all traffic consultants
which are one of the vital elements for building up transportation system GIS data base
(Zulkiple, et. al. 2004).
4
Appointment of a registered TIA
Consultant
Implementation of the TAP &
update of the transport master plan
Assessment of the existing
conditions & proposed development
Appointment of the Detail Design
Consultant for the proposed plans
Scooping of the study and setting
up criteria & procedures
Submission of the TIA report for
the approval of the Authority
Study the transport master plan of
the planning/approving authorities
Update the TIA report to meet the
latest changes
Traffic generation analysis
Submission of draft TIA report to
Client/ Planners/ Architects
Assessment of:
• Accessibility
• Circulation & Parking
• Pedestrian & Public Transport
Proposal for an affordable
Transport Action Plans (TAP) and
preparation of the TIA report
Figure 4: Flowchart of the proposed traffic impact assessment procedures
The new guidelines also give more emphasize to the provision of the pedestrian and public
transport facilities such that adequate study must be conducted as to ensure the safe and
reliable movement of the non-vehicular traffic while providing efficient network for the private
vehicle. Current traffic impact assessment practice is often over estimated with the assumption
that 100% of generated traffic will be of private vehicle that has to be mitigated at the access to
the main road. The split to public transport is used only as basis for the provision of the public
transport facilities such as bus stop, pedestrian walkway and pedestrian crossing.
Despite considering all possible elements and in the absence of transportation master plan and
or linkage to GIS data base, isolated actions may well be implemented which, whilst achieving
their immediate objectives, exacerbate other existing problems.
DEVELOPMENT OF AN
ASSESSMENT MODEL
INTERACTIVE
TRAFFIC
IMPACT
General approach to develop the proposed model is outlined in figure 5. Essentially, having a
regional traffic model in possession will be a great advantage to the assessor of the TIA of a site
development. Therefore, the first step required in standardizing the traffic impact study
approach is to develop a regional traffic model that contains the required elements for validation
purposes such as permanent traffic census station and well updated socio-economic
parameters. Operational parameters of the traffic model such as congestion level, road density
and travel speed are other elements to be monitored and updated depending on the scope and
needs of the study. If possible generalized elements such as network total time saving and total
distance travel should be included to the list of the validation parameters.
5
Presentation & validation tools
Regional traffic
model/data base
TIA of proposed
development site
by standardized
procedure
Site local traffic
model (those with
multiple access)
Store traffic data
and road network
information in
GIS-T format
Links & junctions
performance and
road safety analysis
Figure 5: Proposed approach for modelling TIA with GIS capabilities
The approach steps of executing the procedures are provided below:
1.
Prepare and review study plan to suit budget and the condition of the study area.
Compile all submitted TIA reports for all committed developments and categorized them
into new, on-going and completed developments. Take note for projects developed in
phases. There is also the possibility that too much data is collected. These are both
waste of resources and hindrance to an understanding of the problem. The data
collected from an adequate survey suppose to contain a lot of information regarding
travel behavior. Analyses of these data are very useful for designing the existing
facilities such as traffic system management or arrangements of public transport
system. Besides, it provides an understanding of the relationship between travel
behavior and the environment so that the relationships can be established and
synthesized quantitatively using modeling techniques.
2.
Locate the site of the proposed development on the regional road network and
determine the accessibility of the development to the trunk road. Manual trip forecasting
is limited to development with single access. Developments with multiple accesses
have to make use of one of the macroscopic traffic models. The zoning and coding
system however must be consistent to that of the regional traffic model (the microscopic
model). The latest regional traffic model available for the study area is provided by the
2nd Highway Network Development Plan Study for Malaysia by Highway Planning Unit
Ministry of Works Malaysia (HNDP, 2005).
3.
For the completed development projects, devise a procedure on how to determine the
overall occupancy rate and generated trips as compared to those of the TIA reports.
This is the main aspect to be resolved because it is the cause of inconsistency for the
assumptions of the generated traffic from the particular developments. Trip generation
can be considered as a decision to make a journey. It examines the relationship
between the number of trips made and certain quantifiable parameters such as trip
purpose, household income, vehicle-ownership and land use. Published trip generation
rates for all types of land use are updated bi-annually by Highway Planning Unit,
Ministry of Works Malaysia (Trip Generation Manual, 2005).
6
Figure 6: Reported and actual occupancy & generated rates
4.
5.
The next stage in TIA is trip distribution-trip assignment-modal split exercises which can
be undertaken manually for a simple two way split that is for distributing trips to two
directions. If there are more that two directions, the trip distribution-trip assignmentmodal split exercise have to be undertaken through systematic (computerised)
modelling techniques such as applying one of those macroscopic or microscopic
software depending on the scope of the study. As a completed transport model has
been assembled, data consistency checks should be followed. Actual traffic counts at
certain location are checked with the volumes from the synthetic model. If there is
discrepancy, the mathematical relationship formed earlier has to be adjusted and this
process is so call calibration. Then, finally the model can be used to forecast future
travel demands. In order to forecast the future travel demands, it is necessary to obtain
as much information affecting travel behaviour as possible such as population,
employment and income distribution. A transport model that satisfactory explains the
present use of the existing transportation system is mandatory guide for future planning
any other transportation system. Forecasting normally involves prediction of the future
demand for travel, the future availability of transport and use of the available transport.
When conducting TIA for certain development, identify and list all affected junctions
(existing and new) on the trunk roads. Compare and code them as per regional road
network nodes and links ID. The new nodes and links created in the local traffic model
can be streamlined with those of the regional traffic model. This procedure will help to
reduce nodes and links redundancies while adding new one and of deleting the less
important one to and from the regional traffic model.
7
Figure 7: Include all affected nodes and links in the regional traffic model
For every node and link, traffic data and travel pattern characteristics should be
obtained from the updated regional traffic volume database. This should include also all
necessary traffic safety aspects which can be based on the grouping of the regional
road accident data base. Information on the major cause of accidents and the proposed
mitigation measures should also be specified by area-wide or route wise basis. The
compilation of traffic accident data in GIS system that is presently limited to the federal
road can now be expanded to the state and local road network. Published traffic volume
counting data at strategic census stations along federal and major state and town
routes are updated annually by Highway Planning Unit, Ministry of Works Malaysia
(Traffic Volume Malaysia, 2005).
Legend
Jabor & West &
South of Terengganu
Kemaman & East &
South of Terengganu
tC
Eas
l Route
Federa
N
Dual 2-lane carriageway expressway
Dual 2-lane carriageway Federal Route
Ex
oast
Dual 2-lane carriageway State Road
Single 1-lane carriageway Federal Route
Single 1-lane carriageway State Road
Other Minor/Local Roads
3
sw
pres
N
By ew
pa
ss
6.
ay
New
Interchange
State
R
Jalan oad C4
Sunga
i Lem
bing
Polisas
tan e
an ng
Ku c ha
r
e
t
In
Telok
Cempedak
Airport
tre
TUDM
ute 2
To
Federal Ro
3
te
ou
Route 12
Muadzam Shah &
Southwest of Pahang
lR
ra
de
Fe
Federal
KL, Maran
& North West
of Pahang
3)
(F R
UIAM
wn
bang
Gam ange
terch
In
y
wa
t Express
East Coas
UMP
ass
Byp
Ce
n
Sg. Lembing
Port
Federal Route 2
Note:
Strategic traffic survey stations are located along
Federal Route and major State Road
Pekan & Southeast
of Pahang
Kuala
Pahang
Figure 8: Traffic volume data & information
8
7.
After the completion of traffic forecasting process, the results need to be evaluated.
Firstly, the computation process and output must be reconfirmed. It is mainly numerical
evaluation to ensure that the model is mathematically correct. Following that, the
apparent accuracy of the forecasts should be examined. Other than evaluation of the
model itself, operational and economic evaluations also need to be carried out. The
purpose of operational evaluation is to check whether a new proposed system or
network is able to satisfy the forecast travel patterns whereas, economic evaluation is to
study the cost-benefit so that to choose the best network proposal which falls within a
given budget constraint, but with maximum benefit to the community by minimizing the
cost of travel. This can be done by using traffic analysis software such as HCS, SIDRA
or other equivalent procedures. The prevailing Level of Service (LoS) can be set as the
benchmarks to determine the “severity” of future developments to the existing road
network system.
Figure 9: TIA analysis process
8.
A graphical dictionary to represent future scenario should be created as visual
description of the traffic impacts mitigation measures as shown in figure 10. For every
scenario, the end product of the analysis should include the list of proposed innovative
and cost effective mitigation measures as to cope with future developments impact.
Effort should also be made to develop a common database for every application such
that data redundancies and double counting is minimized. This is actually the gist of the
GIS application in traffic and transportation studies. In this aspect, the GIS Unit of Road
Branch, Public Works Department, Ministry of Works Malaysia has been developing the
national road network with GIS capabilities call SUTRA (Abdullah, 2004).
9
Figure 10: Graphical dictionary of future scenario
9.
The relevant data and results of the TIA study should be updated into the custodian GIS
portal. From time to time, the custodian should transfer the latest version of the regional
traffic model into the main portal for website application. With the Local Authority
functioning as the custodian of the GIS system, all new developments can be imposed
to be subjected to the proposed TIA procedures.
Figure 11: Validation and update of traffic models
10
GIS IMPLEMENTATION FOR THE NATIONAL ROAD NETWORK
IN MALAYSIA
The Public Works Department of the Ministry of Works Malaysia (PWD) has been appointed by
Malaysia Centre Geospatial Infrastructure (MaCGDI) as one of the prime data custodians as
well as the lead agency that is responsible to build up relevant spatial databases and propose
the national standard for roads dataset. MaCGDI is an infrastructure setup at the national level
to enhance data exchange among data users and makes sure that the required data are
collected and conform to national as well as international standards. It is therefore a priority of
PWD that complete digital maps of Federal and States Road Network are available particularly
for uses of GIS-based and Geo-spatial applications. Transportation infrastructure management
for PWD are being accomplished through a GIS based road information and management
system that provide for extensive database querying in a user-friendly environment at the
departmental level (Abdullah 2006).
GIS implementation in PWD started as a research project in 1993 that aim to initiate,
implementing and monitoring the usage of GIS technology in the department by the formation of
SUTRA, the long term GIS project for PWD. SUTRA has been developed into 5 phases since it
inception in 1993. Phase 1 has been a standalone `proto-type' with users from various units and
branches contributed for the existing attribute data. The first product was introduced in
December 1995. In phase 2 the network base maps are digitized. Data collected in phase 1 was
updated and expanded with the collaboration of all units within the department. Personnel form
the various branches were trained to develop their knowledge on concept and tools of GIS so
that they would be able to handle data and develop applications. In phase 3 the base maps is
link to data extension and provide facility for new and from other application to these maps.
Everything needed is initially developed on SUTRA desktop before making use of the
departmental networking system. In phase 4, the work of data capturing in form of points, lines
and polygon using GPS technology was outsourced to several vendors. PWD is responsible on
coordinating, verifying the accuracy of the data and to ensure that the collected data meets its
requirements. The process of verifying the integrity of the captured data was completed by
2004. Phase 5 (the current stage) is the process of updating and maintenance of the existing
data and to capture new features. The Road Information and Management System (RIMS) that
is used by Road Branch professional to plan, monitor, update and maintained the road features
and related data is being produced at the moment. For the data to be up to-date, the
coordinator at respective state must create their own GIS teams which consist of the
representative from district level PWD. This team will update the data periodically at the district
level.
Overall the GIS System development of SUTRA utilises a number of models developed using
the software or system packages namely EMME2 for network analysis of road infrastructure,
HDM4 for road and traffic volume analysis, BMS for bridge management system, MAAP for
accident data analysis, MARRIS for road registration, SKALA for project monitoring system,
SEPAKAT for human resource system, SIMS for slope information management system,
SMART for slope management and risk tracking system and SPRS for slope priority ranking
system. Data integration and updating is managed by the custodians and others who have
interest on the GIS system can gain access to display, query and analyse data when formal
application is made. Figure 12 indicates the completed routes map in GPS and GIS format.
11
(a) Initial (GPS based)
(b) Final Product
Figure 12: Completed road map of Peninsular Malaysia
The available road dataset can also be access through Malaysian Centre for Geospatial Data
Infrastructure (MaCGDI) website: http://www.macgdi.gov.my and individual need to sign up to
become registered users of the MyGDI (Malaysian Geospatial Data Infrastructure) application.
THE LAND USE - ROAD DEVELOPMENT DENSITY MODEL FOR
KUANTAN
Mohamad and Muhammad (2006) has developed an interactive land use – road development
density model for Kuantan by combining a set of conventional modelling techniques and an
open source simulation application called UrbanSim (2006). In assisting the modelling process,
a GIS (Arc View) is used to establish the geospatial database which includes data of various
forms and from various sources. The model is regressed by least square fitting method and
calibrated to study the level of acceptability. For the future land use plan, the model is then used
to predict the road density level and again GIS is applied to import the forecasted data and
graphically display the distribution. The results demonstrate that only five out of eighteen
independent variables tested show the significant effects on the road density for the town.
In the study, the relationship between land use and transportation activities is described
graphically as follows:
Figure 13: Relationship between land use and transportation activities (Source:
Rosenbaum and Koenig 1997)
The modelling strategy for this study was based upon empirically solving these two separate but
interrelated land use dynamics g(•) and transport dynamic f(•) functions sequentially as shown
in figure 14.
12
Figure 14: Modelling sequence (Source: Mohamad and Muhammad 2006)
The methodology of the study involved the following steps:
1.
Data modelling with UrbanSim.
This is a data intensive activity for collection and analysis of the land use (spatial
distribution), household, employment, property and transportation related data. GIS is
an integral part of the model as it is used to provide the land use data required for
UrbanSim to perform the simulation of urban growth.
2.
Geospatial mapping and analysis
Basic parameters of a base year data are prepared in the following format for input into
UrbanSim model:
•
A map subdivided into 1 km x 1 km grid.
•
Total number of households within a grid cell.
•
Percentage of occupied area for housing within a grid cell.
•
Percentage of occupied area for roads within a grid cell (the road density).
•
Distance from the centre of grid cell to the nearest major highways or arterial
roads.
In preparing the above datasets, a number of analytical functions including map overlay,
distance measurement and attribute data manipulation are applied to extract the
required information using the GIS.
3.
Development of geospatial database
A geospatial database is a database that contains objects with locational information. In
this study, all hardcopy maps representing themes related to the study are digitized and
transformed into ground coordinates. The datasets available include:
•
Boundary of the study areas
•
Land use
•
Road network
•
Boundary of housing area
•
Boundary of planning blocks
•
1 km x 1 km grid map
To complement the map as the basic source document to extract the land uses, aerial
photographs and remote sensing images are also used. The processing procedures for
these image data are mainly the coordinate transformation and image interpretation.
13
4.
Feature clipping
Since UrbanSim requires the entry of the parameters to be made according to grid cell
location, all features contained in a particular map layer have to be clipped in a 1 km x 1
km square. This layer is used to clip whatever feature, from which statistical information
related to that features within any particular grid cell boundary can be extracted (e.g. the
total length of a road network and the percentage of households).
5.
Analysis of overall land use pattern
The land use pattern can be analysed visually or statistically. Visualization can be made
by portraying the types in different colours and referred to the map legend. Statistical
analysis on the other hand can be made by selecting records that represent a certain
type of land use and computing a particular attribute required such as the total area.
Further computations such as conversion of measuring unit and the proportion of area
according to the land use types can be made if necessary.
6.
Extraction of spatial parameters
Spatial analysis tools available in the GIS are used for map overlay and neighbourhood
search in term of determining the total number of household within a particular cell or
the distance from a particular cell centre to a highway.
7.
Development of regression model
Using the base year data, a multivariate regression model that define the interaction
between the dependent variable, road density, and the independent variables are
developed by removing any co-linearity between the variable as to ensure that the final
set of independent variables is truly independent of each other, and the only interaction
that exists is that between the independent variables and the dependent variable.
The removal of collinear independent variables is done through a statistic method called
the Variance Inflation Factor (VIF) where a large VIF value, i.e. VIF > 4, indicates the
existence of co-linearity in a specific variable. Thus, any independent variable that
produces a VIF value greater than 4 is removed from the final regression equation. The
computations of the VIF for each of the independent variables are done using SPSS
statistical software.
As a final step in getting the regression equation, the independent variables that are not
significant at α=0.05 level are also removed. Thus, the final regression equation
contains variables that are significant as well as variables that are not co-linearly related
with other independent variables.
8.
Model calibration
The predicted road density for a base year is compared to the actual road development
density for the same year as to determine the prediction error in term of the mean errors
followed by the t-test.
9.
Road development density forecasting
Having established the base year model, the road development density of any future
year can now be forecasted. As a test, the variables for the year 2010 are used to
compute the percentage of space required for road development of each square grid.
The numerical results of this computation are then exported into Arc View GIS where
graphical representation of the road development density level is displayed.
The major outcome of the study as expected is the establishment of a road development
density model in relation to the variation of land uses as follows:
Road development density = 1.721E-5*P5 + 8.555E-7*P8 + 3.788E-3*H3
14
where:
P5 = Commercial area
P8 = Industrial area
H3 = Average household income
Figure 15 shows the actual and modelled road development density for Kuantan in the year
2000 which gives an error of 5.06 when compared. Figure 16 shows the predicted road
development density for Kuantan in year 2010 using the simulated land use changes given by
UrbanSim model.
(a) Actual
(b) Modelled
Figure 15: Actual and modelled road development density of Kuantan in year 2000
(Source: Mohamad and Muhammad 2006)
Figure 16: Predicted road development density of Kuantan in year 2010 (Source:
Mohamad and Muhammad 2006)
CONCLUSION AND RECOMMENDATIONS
The successful implementation of the interactive procedure will depend on the efforts to store
the site traffic impact assessment data into a common traffic GIS database (GIS-T). When there
15
is a need to conduct a new site traffic impact assessment study, the GIS-T database can be
referred for gathering prevailing traffic and land use data of the study area. The TIA can then be
carried out and the process to store and update the GIS-T database will be continuous as 2-way
system. Having the GIS-T database will also serve the need of the approving authorities in their
day-to-day planning needs and as a decision-support mechanism for verification purposes.
Hence, the approach in the development of the GIS-T model will be needs driven rather than
adopting a pre-conceived plan. In addressing this factor, a key issue, data standardization
needs particular attention from both the consultants and the approving authorities. This is to
ensure that the common database is truly a compilation of common data that is usable by every
party involved. Technology transfer or training, which once was critical issues of GIS
implementation in governmental departments in the early 90s, will be tackled by developing a
user-friendly procedure for traffic impact studies.
REFERENCES
Abdullah, MR 2004, ‘Current status of GIS implementation in JKR’, 1st national GIS conference
and exhibition 2004, PWTC, Kuala Lumpur.
Highway Planning Unit 2005, Trip Generation Study Report, Public Works Department, Ministry
of Works Malaysia.
Kuantan
2006,
Goggle
Search,
http://www.malaysiasite.nl/kuantaneng.htm.
viewed
30
October
2007,
Mohamad NS & Muhammad ZS 2006, GIS as a supporting tool in the Establishment of land use
–
road
density
model,
GISdevelopment.net,
viewed
6
August
2007,
http://www.gisdevelopment.net/application/urban/agglomeration/mm026pf.htm.
REAM 2005, Draft Manual of REAM Traffic Impact Assessment (TIA) Guidelines. Road
Engineering Association Malaysia. (Not published).
Rosenbaum, AS and Koenig, BE 1997, Evaluation of Modelling Tools for Assessing Land Use
Policies and Strategies, Report EPA420-R-97-007, Ann Arbour, MI: Office of Mobile Sources,
U.S. Environmental Protection Agency.
UrbanSim 2006, University of Washington, Seattle, USA, viewed 7 August 2007,
http://cuspa.washington.edu/people/.
Zulkiple, A, OK Rahmat, RAA & Ismail, A 2004, ‘Developing interactive traffic model with GIS
capabilities’, 3rd national technical post graduate symposium (Tech’pos04), Universiti Malaya,
Malaysia, 5pp.
Zulkiple, A, OK Rahmat, RAA & Ismail, A 2005, ‘National traffic impact assessment (TIA)
guidelines for Malaysia – a step forward for sustainable development’, 23rd conference of
ASEAN Federation of Engineering Organizations (CAFEO – 23), 9pp.
ACKNOWLEDGEMENTS
My sincere appreciation to Department of Education, Science and Training (DEST) of the
Australian Government for sponsoring my Endeavour Malaysia Research Fellowship
attachment at University of South Australia. My special thanks to Professor MAP Taylor and
colleagues at Transport System Centre, UniSA for making my stay in Adelaide a memorable
one.
AUTHOR BIOGRAPHIES
Adnan Zulkiple is an associate professor at Universiti Malaysia Pahang and the current
chairman of Highway and Transportation Engineering Technical Division of Institution of
Engineers Malaysia.
16

Interactive traffic impact assessment study for Kuantan

Transcription

Similar documents

Citrawarna Malaysia

Brief - Juwita Suwito

Winston County, Louisville Tornado: DeSOto County GIS

Traffic Signals Perth March2015

POWERED BY HERBALIFE

Hi Everyone, WSFFM welcomes some new members to our

national eye hospital based optometry degree programme in malaysia

GIS Department Alamance County

catering rating (cr)

CYBERJAYA

Hotel Grand Continental • KUANTAN