Proceedings of the 9th Asia Pacific Conference on Transportation & the Environment, 2017
Investment on transport infrastructure is a significant component in a country’s budget as it is ... more Investment on transport infrastructure is a significant component in a country’s budget as it is identified as a key factor to facilitate the country’s development. At the same time demand for transportation is positively correlated with the development. With this increasing demand for transport infrastructure and limited funding available, it is necessary to prioritise appropriate projects. Current appraisal practices at the early stages of projects fail to identify some important criterions and therefore, may ultimately end up not selecting the most appropriate project(s) which addresses contemporary concerns. Therefore the objective of this study is to identify a cost effective method and factors that should be considered in evaluating alternatives at the early stages of transport infrastructure projects. Both academic and grey literature was reviewed to identify current practises; methodologies and factors concerned in the recent past. Most of the time feasibility reports used descriptive format and often gave vague conclusions. Therefore the final selection of alternative(s) is implicit. A performance matrix was developed in this study based on multi criteria analysis linear additive model. This method was primarily selected as it is easy to use in practise. In addition to the traditional criterions, this matrix contains new criterions that should be looked into with the current interests. A case study for Kandy expressway alternative selection based on this developed performance matrix is presented in this paper. In addition to the new matrix, a modified scoring system was used in the analysis to minimise the variations, as scores are given by different experts. Further, analysis was compared with the view of different experts and results of sensitivity analysis to address the possible arguments on weight given to each criterion.
Artificial islands are considered as a lucrative option for countries facing land shortage and co... more Artificial islands are considered as a lucrative option for countries facing land shortage and congestion. However, many countries such as, Australia, China, Canada, Hong Kong, Japan, UAE and Maldives have constructed such artificial islands for various reason. The Colombo Port City is an offshore artificial island which will be constructed next to the extended Colombo harbour in Sri Lanka which has a gross land area of 269 hectares (2.66 km). The main purpose of this city development is to offer an eminent potential for business, leisure and tourism, high quality of living not only for Sri Lankans but also for internationals. The land use of the new city will consist of residential developments, shopping areas, hotels, apartments, offices, educational institutes, recreation areas, a variety of sport facilities, marinas as well as a supporting transportation network. Colombo City is full with congestion most of the times and recent studies have found that the average vehicle speed h...
<jats:title>Abstract</jats:title> <jats:p>Trucks generate more externalities (e... more <jats:title>Abstract</jats:title> <jats:p>Trucks generate more externalities (environmental and social) than passenger vehicles, especially when trucks divert off freeways. When toll charges increase, such as the significant recent rise in Mel-bourne, Australia, more trucks tend to avoid toll roads (quality roads), generating more externalities. This diversion adds sub-stantial negative impacts on residents, the environment, and so-ciety. In fact, determining an optimum toll charge for freight ve-hicles is a crucial decision to be made by policymakers consid-ering socioeconomic aspects. The objective of this study is to develop an approach to design an optimal toll pricing scheme for multiclass vehicles, including specific truck types, consider-ing both direct costs and externalities. Additionally, the study developed an approach to identify the tradeoffs between vari-ous objectives of the designed scheme considering given con-straints. Nonlinear programming and user equilibrium techniques are used to model the problem, and the costs (direct costs and externalities) are quantified for Victoria, Australia. This nonde-terministic polynomial-time hard (NP-hard), nonconvex problem with nonlinear constraints was solved using the nondominated sorting genetic algorithm (NSGA) II. The model was applied to both a small-sized hypothetical network and a real network, with static demand conditions to illustrate differences between common toll schemes. Results are presented for Pareto-optimal solutions.</jats:p>
Research in Transportation Business & Management, 2021
Abstract Stakeholder acceptance of any transport policy is crucial for its successful implementat... more Abstract Stakeholder acceptance of any transport policy is crucial for its successful implementation and sustainability. Many initiatives have failed in the past mostly due to stakeholder non-acceptability. As a result, the multi-stakeholder approach towards solving transportation problems is essential for sustainable transportation in the future. This study is focused on how different toll charging policies are perceived by various stakeholders and their level of acceptability. Various toll charging policies are considered where each toll scheme is optimizing at least one of the multi-stakeholder objectives such as user cost, social cost, environmental cost or the rate of return for investment. In addition, for comparison purposes, the currently established toll scheme is also added to the list. Even though each toll scheme is favoured by one or a few stakeholders (objectives) the overall acceptance from all the stakeholders is questionable. Therefore, the Multi-Actor Multi-Criteria Analysis (MAMCA) methodology has been used to evaluate all toll schemes and to identify the most suitable toll scheme considering multiple stakeholders. Different stakeholder opinions are explicitly considered in MAMCA and have been tested and used to successfully evaluate many solutions in the past. From this study, it was found that out of 10 alternatives 3 toll schemes are better at serving all stakeholders interests. It is important to note that in all three solutions heavy vehicles are charged less compared to light vehicles, which is against the present practice of charging heavy vehicles higher tolls.
A driving cycle is a speed time profile which represents the driving characteristics of a selecte... more A driving cycle is a speed time profile which represents the driving characteristics of a selected area. This can be of use to both legislative and non legislative purposes such as development of emission inventory, determination of fuel consumption etc. As driving cycles are dependent on the traffic constituents, driver behaviour and road conditions established driving cycles cannot be used in Sri Lanka. Hence the objective of this research is to develop a methodology and to constructa driving cycle(s) which represent given set of conditions in Sri Lanka such that it can be use to establish emission inventory in future. To achieve these objectives, it is necessary to collect and analyse the on road speed-time data on selected routes which will represent the driving patterns of urban or rural conditions. Due to the restriction of time and resources, study was limited to one transport corridor, anurban condition and for light vehicles only. A sample driving cycle was developed based on the data collected on the Galle Road, section from Katubedda to Fort using on board method. Cycle was developed using micro trip based cycle construction and computer application was developed to aid this purpose. In this study we observed average speed 21.37km/h, average running speed 25.78km/h, average acceleration 2.03km/h/s and average deceleration 2.02km/h/s with acceleration, deceleration, cruising and idling proportions of 27.37%, 23.70%, 31.43% and 17.49% respectively for selected urban condition. This study would facilitate the further studies on development of driving cycles for other conditions and could be of use for traffic engineering studies as well as sustainable development
Introduction of a roundabout is a proven method of minimizing delays and risks at an intersection... more Introduction of a roundabout is a proven method of minimizing delays and risks at an intersection simply due to the reduction in number of conflict points, implementation of give way rule, single directional circulation and reduced speed due to the lateral displacement. However, there arestill opportunities and desires for improvements in reducing the delay and increasing the safety at roundabouts. The safety risk and delay is significant when vehicular volume is high. Roundabout performance can degrade if precautions are not taken eitherduring the design or the operation phases. Therefore this study is focused on seeking traffic engineering solutions to minimize the delay and risk of accidents at roundabouts to be implemented at design and construction stages. During the study, it was realized that a solution should be obtained through both literature reviews and data analysis. Therefore a comprehensive literature review was carried out on related sub topics. Crash and geometric data were collected for two normal roundabouts and analysed. Increasing the diameter of the central island up to the required level specified by the guidelines, decreasing the approach curve radius, elevating the circulating carriageway with respect to the approach carriage by introducing a ramp for the entering vehicles are proposed for the roundabouts as traffic engineering solution
Proceedings of the 9th Asia Pacific Conference on Transportation & the Environment, 2017
Investment on transport infrastructure is a significant component in a country’s budget as it is ... more Investment on transport infrastructure is a significant component in a country’s budget as it is identified as a key factor to facilitate the country’s development. At the same time demand for transportation is positively correlated with the development. With this increasing demand for transport infrastructure and limited funding available, it is necessary to prioritise appropriate projects. Current appraisal practices at the early stages of projects fail to identify some important criterions and therefore, may ultimately end up not selecting the most appropriate project(s) which addresses contemporary concerns. Therefore the objective of this study is to identify a cost effective method and factors that should be considered in evaluating alternatives at the early stages of transport infrastructure projects. Both academic and grey literature was reviewed to identify current practises; methodologies and factors concerned in the recent past. Most of the time feasibility reports used descriptive format and often gave vague conclusions. Therefore the final selection of alternative(s) is implicit. A performance matrix was developed in this study based on multi criteria analysis linear additive model. This method was primarily selected as it is easy to use in practise. In addition to the traditional criterions, this matrix contains new criterions that should be looked into with the current interests. A case study for Kandy expressway alternative selection based on this developed performance matrix is presented in this paper. In addition to the new matrix, a modified scoring system was used in the analysis to minimise the variations, as scores are given by different experts. Further, analysis was compared with the view of different experts and results of sensitivity analysis to address the possible arguments on weight given to each criterion.
Artificial islands are considered as a lucrative option for countries facing land shortage and co... more Artificial islands are considered as a lucrative option for countries facing land shortage and congestion. However, many countries such as, Australia, China, Canada, Hong Kong, Japan, UAE and Maldives have constructed such artificial islands for various reason. The Colombo Port City is an offshore artificial island which will be constructed next to the extended Colombo harbour in Sri Lanka which has a gross land area of 269 hectares (2.66 km). The main purpose of this city development is to offer an eminent potential for business, leisure and tourism, high quality of living not only for Sri Lankans but also for internationals. The land use of the new city will consist of residential developments, shopping areas, hotels, apartments, offices, educational institutes, recreation areas, a variety of sport facilities, marinas as well as a supporting transportation network. Colombo City is full with congestion most of the times and recent studies have found that the average vehicle speed h...
<jats:title>Abstract</jats:title> <jats:p>Trucks generate more externalities (e... more <jats:title>Abstract</jats:title> <jats:p>Trucks generate more externalities (environmental and social) than passenger vehicles, especially when trucks divert off freeways. When toll charges increase, such as the significant recent rise in Mel-bourne, Australia, more trucks tend to avoid toll roads (quality roads), generating more externalities. This diversion adds sub-stantial negative impacts on residents, the environment, and so-ciety. In fact, determining an optimum toll charge for freight ve-hicles is a crucial decision to be made by policymakers consid-ering socioeconomic aspects. The objective of this study is to develop an approach to design an optimal toll pricing scheme for multiclass vehicles, including specific truck types, consider-ing both direct costs and externalities. Additionally, the study developed an approach to identify the tradeoffs between vari-ous objectives of the designed scheme considering given con-straints. Nonlinear programming and user equilibrium techniques are used to model the problem, and the costs (direct costs and externalities) are quantified for Victoria, Australia. This nonde-terministic polynomial-time hard (NP-hard), nonconvex problem with nonlinear constraints was solved using the nondominated sorting genetic algorithm (NSGA) II. The model was applied to both a small-sized hypothetical network and a real network, with static demand conditions to illustrate differences between common toll schemes. Results are presented for Pareto-optimal solutions.</jats:p>
Research in Transportation Business & Management, 2021
Abstract Stakeholder acceptance of any transport policy is crucial for its successful implementat... more Abstract Stakeholder acceptance of any transport policy is crucial for its successful implementation and sustainability. Many initiatives have failed in the past mostly due to stakeholder non-acceptability. As a result, the multi-stakeholder approach towards solving transportation problems is essential for sustainable transportation in the future. This study is focused on how different toll charging policies are perceived by various stakeholders and their level of acceptability. Various toll charging policies are considered where each toll scheme is optimizing at least one of the multi-stakeholder objectives such as user cost, social cost, environmental cost or the rate of return for investment. In addition, for comparison purposes, the currently established toll scheme is also added to the list. Even though each toll scheme is favoured by one or a few stakeholders (objectives) the overall acceptance from all the stakeholders is questionable. Therefore, the Multi-Actor Multi-Criteria Analysis (MAMCA) methodology has been used to evaluate all toll schemes and to identify the most suitable toll scheme considering multiple stakeholders. Different stakeholder opinions are explicitly considered in MAMCA and have been tested and used to successfully evaluate many solutions in the past. From this study, it was found that out of 10 alternatives 3 toll schemes are better at serving all stakeholders interests. It is important to note that in all three solutions heavy vehicles are charged less compared to light vehicles, which is against the present practice of charging heavy vehicles higher tolls.
A driving cycle is a speed time profile which represents the driving characteristics of a selecte... more A driving cycle is a speed time profile which represents the driving characteristics of a selected area. This can be of use to both legislative and non legislative purposes such as development of emission inventory, determination of fuel consumption etc. As driving cycles are dependent on the traffic constituents, driver behaviour and road conditions established driving cycles cannot be used in Sri Lanka. Hence the objective of this research is to develop a methodology and to constructa driving cycle(s) which represent given set of conditions in Sri Lanka such that it can be use to establish emission inventory in future. To achieve these objectives, it is necessary to collect and analyse the on road speed-time data on selected routes which will represent the driving patterns of urban or rural conditions. Due to the restriction of time and resources, study was limited to one transport corridor, anurban condition and for light vehicles only. A sample driving cycle was developed based on the data collected on the Galle Road, section from Katubedda to Fort using on board method. Cycle was developed using micro trip based cycle construction and computer application was developed to aid this purpose. In this study we observed average speed 21.37km/h, average running speed 25.78km/h, average acceleration 2.03km/h/s and average deceleration 2.02km/h/s with acceleration, deceleration, cruising and idling proportions of 27.37%, 23.70%, 31.43% and 17.49% respectively for selected urban condition. This study would facilitate the further studies on development of driving cycles for other conditions and could be of use for traffic engineering studies as well as sustainable development
Introduction of a roundabout is a proven method of minimizing delays and risks at an intersection... more Introduction of a roundabout is a proven method of minimizing delays and risks at an intersection simply due to the reduction in number of conflict points, implementation of give way rule, single directional circulation and reduced speed due to the lateral displacement. However, there arestill opportunities and desires for improvements in reducing the delay and increasing the safety at roundabouts. The safety risk and delay is significant when vehicular volume is high. Roundabout performance can degrade if precautions are not taken eitherduring the design or the operation phases. Therefore this study is focused on seeking traffic engineering solutions to minimize the delay and risk of accidents at roundabouts to be implemented at design and construction stages. During the study, it was realized that a solution should be obtained through both literature reviews and data analysis. Therefore a comprehensive literature review was carried out on related sub topics. Crash and geometric data were collected for two normal roundabouts and analysed. Increasing the diameter of the central island up to the required level specified by the guidelines, decreasing the approach curve radius, elevating the circulating carriageway with respect to the approach carriage by introducing a ramp for the entering vehicles are proposed for the roundabouts as traffic engineering solution
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Papers by Loshaka Perera