Traffic Impact Assessment on a New Commercial Development in the Neighbourhoods of Ampang Town in Selangor

Traffic impact assessment (TIA) on a proposed commercial development in the neighbourhoods of Ampang Town in Selangor was conducted. In this study, trip rate analysis and regression analysis were carried out to assess future traffic expected to be generated by the proposed new commercial development. Calculations of trips were based on the Malaysian Highway Planning Unit (HPU) Trip Generation Manual (TGM) Malaysia 2010 related to a category of proposed new commercial development. Before and after construction study on the proposed new commercial development at neighbouring critical intersections and roads was carried out to determine existing and projected traffic volumes. A Statistical Package for the Social Sciences (SPSS) software was used to analyse traffic growth rate. This procedure uses a growth factor in the traffic data to show an increase in demand for transport journeys in the future. Then, intersections and roads traffic performances were analysed using the Signalised and Un-signalised Intersection Design and Research Aid (SIDRA) software. Result of SIDRA analysis with traffic projection horizon of year 2026 shows deterioration in Level of Service (LOS) D at one of the existing main junctions leading to the proposed new commercial development. Finally, traffic improvements were proposed to address future impact of generated traffic caused by the proposed new commercial development. Consequently, this study has provided a framework for TIA preparation and would assist developers and local authorities in their decision making to meet all the requirements needed in the design and improvement of traffic flow.


INTRODUCTION
A proficient transportation system has a great importance on the infrastructural as well as the overall economic development of a country.Therefore, National Transformation Program (NTP) of Malaysia under its 10 th.Malaysia Plan has produced better road network connectivity, longer road as well as larger airports and ports.Sperling and Gordon (2010) estimated by 2030, more than two billion vehicles expected to be generated by this world where California and China are having the most troublesome emissions problems.
These problems may also due to population growth not only due to traffic capacity of vehicles that are too heavy but also because of economic and social factors, particularly when there is a little effort in public transport provision.Based on published document such as HPU (2015) and the busy road network as we can see in Figure 1, the traffic volume of Ampang Town is growing at an alarming rate with a large number of population and development projects.The town also contains several developments such as an International School of Kuala Lumpur (ISKL) secondary campus, hospitals and a few small shopping complexes such as Ampang Tesco (beside the MRR2 near the Pandan Jaya exit).
Thus, the town is expected to witness higher rate of population growth including increase in traffic volumes and may cause recurring congestion on roads from time to time.However, without proper understanding of development impact on the existing road network it will have serious consequences for economics and social well-being such as traffic congestion.Therefore, as stated in Minhans et al. (2013), Nazir Huzairy Zaki (2013) and Sharmeen et al. (2012) have suggested Traffic Impact Assessment (TIA) needs to be carried out to determine whether the existing road network surrounding the proposed new development will be able to handle additional traffic while still maintaining an acceptable level of service (LOS) and to identify roadway improvements to minimize the traffic impact such as installation of a traffic signal or a roundabout, creating additional lanes and others.
For this study, the objectives of TIA are underlined below: 1. To analyse and examine access arrangement and impact of the proposed new development on the adjacent external roads and junctions in immediate vicinity of the development site.2. To identify the pattern of traffic flow and the impact of the traffic growth caused by the proposed new commercial area for the year of 2026.3. To propose appropriate improvements or mitigation on the transportation network for especially the existing roads in Ampang.Hence, in order to achieve the study objectives, the following tasks have been performed: 1.To carry out road and junctions inventories to determine the present road and junction characteristics in the vicinity of the proposed development site.This includes determining the number of lanes, junction control and layout as well as other existing traffic facilities near the project site.4. To forecast the amount of traffic likely to be generated by and attracted to the proposed and surrounding development taking into consideration the proposed development components. 5. To distribute and assign development traffic to the adjacent road network based upon the present traffic pattern.6.To investigate the impact of the development traffic on the external roads and junctions in terms of their capacities and performances and recommend mitigation measure to accommodate any possible impacts if necessary.7. To assess the access arrangement serving the new development site and advice traffic issues associated with the proposed access points.

METHODOLOGY
The first step of the study starts with extensive literature survey and review to develop clear understanding of the concept of TIA.Then select the area for study.In this paper, a proposed new commercial development project by Perfect Eagle Development Sdn. Bhd., hereinafter refer as the Developer was planning to build office tower on Lot PT 8881, Bandar Ampang, Daerah Hulu Langat, Selangor Darul Ehsan has been selected as the study area.The primary data was obtained by carrying an inventory in the Ampang Town to assess future traffic conditions and the mean trip rates.Secondary data on traffic and land uses in terms of type and scale of all the land uses were also obtained from the Dewan Bandaraya Kuala Lumpur (DBKL).Highway Planning Unit document on Trip Generation Manual (TGM) Malaysia 2010 was used to estimate the mean trip rates for new commercial development.The projected traffic volumes at critical intersection and road during before and after construction near the proposed new commercial development was analysed using SIDRA Intersection 6.1 (2015) software (Signalized and Un-signalised Intersection Design and Research Aid) to determine the traffic performance of roads and intersections.The success of SIDRA Solutions products has been built on reputation and career-long achievements of Dr Rahmi Akçelik, who is the company director and author of SIDRA Intersection and SIDRA Trip.In addition, IBM Statistical Package for the Social Sciences (SPSS) version 22.0 (2015) software was used in this study to analyse the rate of traffic growth as described in details in Barrette el al. (2001).This procedure uses a growth factor in the traffic data to show an increase in demand for transport journeys in the future.
Finally, traffic improvements as described in Geetam and Mohan ( 2016) have been proposed to address the impact of traffic caused by the proposed new development in the future.The study methodology is summarized in a flowchart as shown in Figure 2.

RESULTS AND ANALYSIS SITE LOCATION
The proposed development site is located to the south of Tesco Ampang and to the north of MRR2 Ampang Petronas Station.Presently, the main roads leading to the development site from Jalan Lingkaran Tengah 2 (MRR2) and Jalan Pandan 1 are Jalan Pandan 5 and Jalan Pandan Prima. Figure 3 shows the location of development site in relation to the existing road and the detail components of the proposed development.

DATA COLLECTION
Procedures described in Ismail Abdul Rahman (1991) have been adopted for data collection as follows: 1. Inventory was carried out at roads and junctions leading to the proposed development site to determine the existing characteristics of roads and junctions such as roadway lanes, width, traffic circulation, junctions' control and layout as well as traffic condition.2. There was six major junctions' in vicinity of the proposed development site expected to receive immediate impact from the proposed development as shown in Performance of the existing roads is measured based upon the volume to capacity (V/C) ratio and LOS.Generally, LOS A and F represent the best and the worst operating conditions respectively while LOS D is considered the acceptable traffic conditions for design criteria in an urban environment.Table 2 shows the results of the overall performances of existing roads.The results of roadway V/C analysis indicated existing Jalan Pandan Prima and Jalan Pandan 5 are operating at acceptable traffic condition with LOS A during morning and evening peak hours.This is reflected during the on-site observation where there was no major traffic congestion at the mid-block section of these roads.Assumptions have been made due to the local road of Jalan Pandan Prima is already in a 3-lane one-way road and most of the drivers are likely to use the highway path rather than local road with signalized junction.

PERFORMANCE OF ExISTING JUNCTIONS
The existing operational performance of immediate junctions to the development site was evaluated as suggested by Ahmad Faiz Nasir (2012) using SIDRA software.The performances of junctions were analysed based on degree of saturation and the results are as shown in Table 3.
Based on the analysis and observations that have been made, Jalan Pandan Prima / Jalan Pandan Prima 2 (J5) is operating at the worst performances during peak evening with level of service LOS D compared to other intersections but still at acceptable traffic condition.Figure 4 shows the plan layout and performance of junction 5 (J5).

FORECAST OF FUTURE TRAFFIC
With reference to HPU Road Traffic Volume Malaysia ( 2015), an annual traffic growth of 3.0% was applied for the existing traffic to reflect the current natural growth of the locality.The adoption of these growth rates over the next ten years is expected to provide a realistic forecast for future traffic demand.The forecast of development traffic is usually undertaken by using trip generation rates.The development traffic forecast and the trip generation rates used to estimate traffic generated by and attracted to the proposed development is based on TGM 2010 Malaysia, as shown in Table 4 and 5 respectively.

PROPOSED TRAFFIC IMPROVEMENT
Based on the understanding of existing traffic characteristic and traffic issues in the vicinity of development site and predicted year 2026 traffic forecast, the following traffic improvement as shown in Geetam and Mohan (2016) have been recommended to ensure smooth flow of traffic and acceptable level of service performance for the existing road and junction.The junctions plan layout and the analysis of expected traffic volume in 2026 for morning and evening peaks are as shown in Figure 5.The outcomes of the analysis are: 1. To proposed junction modification of the existing Jalan Pandan Prima / Jalan Pandan Prima 2 Left-in/left-out Stop-control Junction (J5) with provision of physical kerb/median at west approach of the junction in order to prevent the illegal right turn movement from Jalan Pandan Prima 2 to Jalan Pandan Prima.2. To proposed a new access junction 1 (AJ1) for the proposed development in a form of left-in/left-out stopcontrol junction.The analysis of future traffic on the adjacent roads will be based on the proposed traffic improvement and the future peak hour traffic volumes.Table 6 shows the total future traffic and the predicted performance of the existing roads leading to development site.The results of future roadway capacity analysis indicated with the proposed road upgrading, the existing Jalan Pandan Prima and Jalan Pandan 5 are expected to operate at acceptable traffic condition with LOS A during morning and evening peak hours in Year 2026.No improvements are required.

2.
To carry out traffic count survey on a weekday at existing roads and junctions in close proximity of the development site.3. To analyse and evaluate traffic condition on the existing road to determine the present traffic flow, traffic composition, peak hours' periods and performance of existing road and junction in the vicinity of the development site.

FIGURE 3 .
FIGURE 3. Location and the detail components of proposed commercial development (Source: Proposed development layout plan)

FUTURE
TRAFFIC IMPACT ON ExISTING JUNCTIONS Future junction performance analysis by including the proposed traffic improvement and future peak hour traffic volumes of other intersections has been carried out; however, the results are still at acceptable traffic condition.The performance of junction is measured in term of degree of saturation and vehicular queues.The outcomes of future Year 2026 junctions' analysis are tabulated as in Table7.The results of future roadway capacity analysis indicated with the proposed junction upgrading, the existing and junctions leading to the development site are expected to operate at acceptable traffic condition with level of service ranging from LOS A to LOS C during morning and evening peak hours in Year 2026.CONCLUSIONTIA can be a very useful tool for engineers, architects and planners to determine the possible adverse effects of a project on the transportation and traffic system.This study introduces the concept, procedure and come up with the solution by traffic improvement on the proposed new commercial development at Ampang Town.The analysis on road efficiency, additional traffic volume and its impact, state performance of surrounding and adjacent roads, statistical modelling and relevant analysis have been used in developing the TIA document.To improve expected traffic congestion due to the new commercial development, additional traffic and traffic growth for year 2026, the study has suggested to consider building a physical kerb/median at the critical junction 5 (J5) and proposed a new Access Junction 1 (AJ1) for the proposed new commercial development.It will assure a smooth traffic flow on the road network in the future.

Table 1
TABLE 2. Existing roads operational performance FIGURE 2. Study methodology flow chart PERFORMANCE OF ExISTING ROADS

TABLE 4 .
Trip generation rates and percentage of trips in and out of study area

TABLE 5 .
Peak hour development traffic forecast (pcu/hour) FIGURE 5. Junction plan layout and expected morning and evening peaks for year 2026 FUTURE TRAFFIC IMPACT ON ExISTING ROADS

TABLE 9 .
Result of regression analysis

TABLE 10 .
Result of Pearson's correlation (r) analysis • By time (year) (Pearson's correlation) FIGURE 6. Statistical analysis summary flows FIGURE 7. Scatterplot graph analysis of the volume of vehicle against time