Browsing by Author "Perera, HLK"

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item: Conference-Abstract
Analysis of optimal expansion level of a single runway airport
(Department of Civil Engineering, Faculty of Engineering, University of Moratuwa, 2022-12) Siriwardena, KDSV; Perera, HLK; Mallikarachchi, C
Air travel is rapidly increasing all over the world and airport capacities are crucial when serving this growing demand. When it comes to airport capacities, whether it is passenger or freight, runway capacity is the key determining factor among many. At the same time, adding a runway to an existing airport is an expensive process from the design itself to obtaining approvals, construction and completion, compared to any other developments associated with an airport such as passenger areas and other service areas. However, despite the cost and other negative external factors involved, most airport authorities tend to make a bold decision to add another runway to the existing airport without looking at optimising existing and future operations. This seems to be the case for the Bandaranaike International Airport (BIA) which made plans to add a second new runway to accommodate future traffic. Therefore, the main aim of this research is to identify how to achieve the optimal expansion of a single-runway airport without adding a second runway. This is achieved by identifying critical parameters that affect the runway capacity and analysing ways to obtain the optimal capacity. Hence, the next appropriate solution to accommodate future traffic growth is to optimise current operations rather than physical expansion, due to drawbacks such as high capital costs, long implementation times, community opposition, and so on. After collecting the necessary data, an analysis was carried out to determine the current capacity and the utilisation of the runway in BIA. From the analysis, it was found that during a peak period more than 50% of the runway capacity is idling, meaning that it is been underutilised heavily at present. In other words, BIA can simply double the operations with the existing runway and now the question is whether BIA expects a growth more than this within the next 15-20 years. Beyond finding out the truly available runaway capacity there are ways to optimise runaway capacities. One such option would be to assist air crafts to evacuate from the runaway in the shortest possible time so that they can conduct the next operations. This was found to be the next largest bottleneck hindering runaway capacity and as a result implementation of highspeed exits have been considered in this study using the REDIM software. In addition, the best departure and arrival sequences were discovered using Python code to utilise the time more efficiently as Runway Occupancy Time (ROT) differs according to the aircraft category. It canbe concluded that the existing runway capacity can be further improved by optimising the current operations, as ROT was reduced by 10%.
item: Conference-Abstract
Analysis of optimal expansion level of a single runway airport
(Department of Civil Engineering, University of Moratuwa, 2022-12) Siriwardena, S; Perera, L; Perera, HLK
Air travel is rapidly increasing all over the world, and airport capacities are crucial when serving this growing demand. When it comes to airport capacity, whether it is passenger or freight, runway capacity is the key determining factor among many others. At the same time, adding a runway to existing airports is an expensive process, from the design itself to obtaining approvals, construction, and completion, compared to any other developments associated with an airport, such as passenger areas and other service areas. However, despite the cost and other negative external factors involved, most airport authorities tend to make a bold decision to add another runway to the existing Airport without looking at optimizing existing and future operations. This appears to be the case for Bandaranaike International Airport (BIA), which made plans to build a second new runway to accommodate future traffic. Therefore, the main aim of this research is to identify how to achieve the optimal expansion of a single-runway airport without adding a second runway. This is achieved by identifying critical parameters that affect runway capacity and analyzing ways to obtain the optimal capacity. Hence, the next appropriate solution to accommodate future traffic growth is to optimize current operations rather than physical expansion due to drawbacks such as high capital costs, long implementation times, community opposition, and so on. After collecting the necessary data, an analysis was carried out to determine the current capacity and the utilization of the runway at BIA. From the analysis, it was found that during a peak period, more than 50% of runway capacity is idle, meaning that it's been underutilized heavily at present. In other words, BIA can simply double the operations with the existing runway, and now the question is whether BIA expects a growth rate greater than this within the next 15-20 years. There are ways to optimize runaway capacities in addition to determining the truly available runaway capacity. One such option would be to assist air crafts in evacuating from the runaway in the shortest possible time without any hindrance to RADAR and wake turbulence separations so that they can conduct the next operations. This was found to be the next largest bottleneck hindering runaway capacity, and as a result, the implementation of high-speed exits has been considered in this study using the REDIM software. In addition, the best departure and arrival sequences were discovered using Python code to utilize the time more efficiently, as runway occupancy time (ROT) differs according to the aircraft category. It can be concluded that the existing runway capacity could be further improved by optimizing the current operations, as ROT was reduced by 10%. ROT reduction leads to a reduction in costs and delays, which would make a significant difference during peak hours. As the world's busiest Airport that operates with a single runway, Mumbai airport handles aircraft at 65-second intervals, and it's important that optimization strategies are implemented at such airports to avoid significant delays.
item: Conference-Abstract
Analysis of suitability of dry-back process in Sri Lankan road pavement construction
(Department of Civil Engineering, University of Moratuwa, 2022-12) Vasavan, V; Mampearachchi, W; Perera, HLK
Moisture content is an important component in the Compaction of pavement layers in road construction. Moisture content in pavement layers is varied by precipitation and environmental factors in the construction and operational stages. If the measured moisture content of the pavement layers exceeds the optimum moisture content, it causes premature pavement failures, such as traffic compaction in the wheel path. Also, this excess moisture content leads to the formation of undulation in the pavement. Therefore, the Dry-back process is widely used in Australia and New Zealand to prevent such pavement failures. The dry-back process is required to prevent the pavement from moisture-related failures. Water is added to the pavement material to achieve a specified density in the construction stage. If the moisture content of the pavement layer exceeds the optimum moisture content, pavement material must be allowed to dry to a certain level below the optimum moisture content. It is known as the dry-back process. Before laying one pavement layer over the other, the water content of the laid pavement must be checked. This is the quality measurement activity for the dry-back process. This research mainly focuses on the dry-back Requirement in Sri Lankan Road pavement construction. The research was carried out using four methods such as survey, material comparison, case study, and practical analysis. First, based on carried out industrial surveys, it was found that the dry-back method is followed in Sri Lankan pavement construction practices without understanding the exact process of it. Second material comparison, In Australia, higher quality materials are allowed for pavement construction when compared with the Sri Lankan Standards. In Australia, field compaction is maintained at a higher value, whereas California Bearing Ratio (CBR) is kept lower than the Sri Lankan materials specification. Various testing methods are practised in Australian Construction processes to ensure the quality of materials compared to Sri Lanka. The third Case study, weather reports, and testing summaries were interpreted to identify the pavement layers with high moisture content, specifically during the rainy season. On the other hand, failures on the pavement surface were identified. Professionals were interviewed regarding these pavement failures, while weather reports and material testing-related data were analyzed. Both approaches clearly illustrate that high moisture content might increase the possibilities of reconstruction of layers, obstruction in the pavement compaction, and pavement failures. Further, this finally practical analysis was carried out in the road sections where cracks are formed on pavements due to moisture content above the optimum moisture content. The moisture content of the pavement layer should be below 60% degree of saturation is preferable for the Sri Lankan pavement condition. This condition is derived from the literature survey and practical analysis of this research. Hence it can be concluded that the dry-back process is a primary requirement in Sri Lankan Road pavement construction.
item: Conference-Abstract
Analysis on design standards of bus terminals in Sri Lanka
(Department of Civil Engineering, University of Moratuwa, 2021-10) Medawatte, V; Sirisoma, N; Perera, HLK
Transportation has become a major component in a countries’ development. Improvement of public transportation along with their infrastructure is a timely need to address its demand. The comfort, safety, and attractiveness of a public transport mode should be ensured in order to promote it among citizens. Buses are one of the main public transport modes in Sri Lanka, which has accessibility to a wider area of the country. In order to attract more people to utilize buses, passengers should be offered with necessary services. Bus terminal is a main component of bus transport network, where bus trips are generated or halted. These bus terminals are utilized by a massive number of passengers daily. Therefore, infrastructure should be developed at these stations under proper standards in order to ensure the quality of service provided. However, the existing terminals are unable to fulfill the basic amenities required by passengers and are not sufficiently designed to ensure comfortable movements inside the terminal. Many passenger-bus conflicts, bus-bus conflicts are commonly experienced in terminals. Entry and exit points creates negative traffic impacts at terminal locations. The main reason for this is the absence of a proper set of guidelines that can be referred to, when constructing bus terminal structures and infrastructure. Currently a set of design standards to be reffered for a bus terminal design within the Sri Lankan context does not exist. The main objective of this study is to introduce systematic bus terminal design guidelines ensuring the supply of complete infrastructure facilities needed for bus passengers. Western Province has been selected as the study area for this research. Western province bus route data is obtained from National Transport Commission (NTC), Western Province Passenger Transport Authority (WPPTA), and Sri Lanka Transport Board (SLTB). The origins and destinations of the bus route data were used to identify the bus terminals within the study area due to the absence of a centralized database. The basic features of these identified bus terminals such as total number of bus routes generated, number of long-distance and short-distance bus routes, number of A/C and non-A/C bus routes generated, and the availability of multimodal facility was obtained by classifying the collected data. A total of 44 bus terminals were recognized within Western Province, disregarding the terminals which generate less than 5 bus routes. A terminal classification was developed considering the nature of the identified bus terminals. The terminals were categorized into four main categories namely Category A, B, C and D. Along with the above classification, a terminal ID was developed considering the basic features identified for terminal classification along with its location details. A questionnaire survey was carried out with a total sample size of 300 respondents distributed among bus passengers and bus terminal staff covering 3 bus terminals from each category (12 bus terminals). The objective of the questionnaire survey was to identify the passenger requirements and the standards of the existing terminal facilities. The passengers’ tendency to use these facilities while traveling and additional facility requirements apart from the available were taken into consideration. Literature related to existing bus terminal guidelines in other countries and the design standards currently used by architects for terminal construction in Sri Lanka were referred. The features of the Sri Lankan bus transport network, such as types of 32 buses and passenger behaviors were taken into consideration. Based on the research finding a guide book was developed to be used in Sri Lankan bus designs. It includes a set of design guidelines are submitted for the drafting of bus terminal designs under several sections. Basic building construction guidelines, layout factors such as bus bays, turning radii, parking requirements, pedestrian space requirements, passenger amenities such as seating requirements, queue lines, terminal staff requirements, information, signages, demand of differently-abled passengers and safety standards were taken into consideration. This code of guidelines would be beneficial as there are no proper designing instructions for bus terminals available for the Sri Lankan context at present. Other than that, certain functional requirements for bus terminals are separately identified as mandatory and optional requirements according to the terminal categories. It would prevent the over-allocation of resources in construction of terminals based on the terminal category. This study recommends to follow the guidelines presented in constructing new terminals considering the features of the terminal facilities. It can also be referred to prioritize the facilities to be addressed in the refurbishment of existing terminals.
item: Conference-Abstract
Analysis on transport mode choices of school children in Colombo District, Sri Lanka
(Department of Civil Engineering, University of Moratuwa, 2020-12) Damsara, P; De Silva, D; Sirisoma, N; Perera, HLK
The increase in the usage of private transport modes for school trips has become a major reason for traffic congestion in Colombo District during peak hours. Colombo District consists of 402 functioning government schools, with a total student population of 374,995. Those schools have been categorized into four categories based on the availability of classrooms. According to the Ministry of Education, there is a limitation which is imposed on the distance from home to school, in the student enrollment process. However, it has been identified that the distances are exceeding the limitation, with respect to the school type and location. As a result, students choose different transport modes based on many factors such as accessibility, connectivity, safety, reliability and comfort. This study focuses on identifying the distances from home to school and the respective transport mode choice of the students in Colombo District. In addition, the factors which affect those school children to avoid public transport modes were analyzed. The quantitative research approach has been used in developing the research methodology in several phases such as factor identification, mode choices and demand distribution. Data collection has been conducted through a questionnaire survey which covers 28 selected schools under four categories, with a total sample size of 2875 in all Divisional Secretariat Divisions (DSDs) of Colombo District. Stratified sampling technique was used to collect data from the above school types. Schools which have classes in all streams up to advanced level (1AB schools) show the highest percentage of students (44%) who travel a distance of 2-10 km from home to school, while other school types show the highest percentage of students (49%) who travel a distance range of less than 2 km. Further, it has been identified that 1AB schools have some students who travel more than 25 km daily for their school trips. School van/bus services are the main mode of transport which is used by the students of schools located in Colombo Municipal Council (CMC) area, while public transport modes such as bus, train and “Sisu-Sariya school bus service” are the main modes of transport which are used by the students outside the CMC area. Active transport modes are the least popular mode of travel in both CMC and Non-CMC area (13% each), while private transport modes, which consists of car/van/jeep, motorbikes and three-wheelers contribute 25% in CMC area and 33% in Non-CMC area. Furthermore, it has been identified that longer travel times, longer waiting times, poor accessibility, less security and less comfort are the main reasons for the students in Colombo District, to not use public transport services. Even though there is a dedicated public transport service (“Sisu-Sariya”), which have been provided for school children, it has been found that there is a considerable usage of private transport modes for school trips in the district. Therefore, this study recommends a procedure to develop an improved public transport system for school trips including a model for trip distribution patterns, network connectivity and system planning to attract more students into public transport services.
item: Conference-Abstract
Applicability of standard density in QC and QA of asphalt surfacing
(Department of Civil Engineering, University of Moratuwa, 2021-10) Rathnasiri, P; Mampearachchi, WK; Perera, HLK
The significance of quality control and quality assurance at the compaction operation in the asphalt pavement has long been recognized by the industry since the compaction maintains the volume of air in the asphalt, which has a profound effect on pavement performance and pavement service life. As a compaction quality control parameter, the degree of compaction, expressed as a percentage ratio between field density and the reference density, is used in the pavement industry. There are several methodologies to establish the reference density to formulate the degree of compaction in the present. However, for decades, measuring densities from daily laboratory compacted samples during construction (Marshall Density) has been the mainstream practice to establish the reference density in Sri Lanka. The major drawback of establishing Marshall laboratory density as a reference density is its inability to represent any unnoticed material or plant variations in the field. This study focuses on solving the aforementioned constraint by developing a new systematic approach called the ‘Standard density method’ to establish the reference density. The standard density is determined as the mean value of densities of Marshal test specimens from morning and evening operations only for a specified number of days after the commencement of construction. This study aims to evaluate the feasibility of the concept of standard density method by comparing current practice with the proposed method. In-place density readings and their respective Marshall laboratory density measurements were collected from different road projects, and the compaction performance was evaluated according to the degree of compaction (at least 97 percent of reference density) in both the existing and proposed methods. To increase the reliability of this comparison, method comparison hypothesis testing (student t-test) was developed for both the existing method and the proposed method to analyze the compaction performance. This t-test was designed to support the alternative hypothesis ‘in-place density > 97% of reference density (from Marshall density & standard density)’. According to hypothesis test results, the analysis reveals a significant correlation in compaction rates between the current and proposed methods (significant at a 5% level of significance). Moreover, the study shows that the hypothesis mentioned above can be rejected only in the standard density method if any material or plant variations have occurred in the project; in addition, these hypothesis rejections appear after a considerable time period from the commencement of the construction.
item: Conference-Abstract
Application of data science technologies to take proactive decisions to control road crashes
(Department of Civil Engineering, University of Moratuwa, 2021-10) De Silva, I; Perera, L; Perera, HLK
Traditionally, road traffic crash analysis and accident modeling resorted to regression models and discrete choice models. Many countermeasures have been identified and implemented but still, the number of crashes and severities are increasing every year. Since road traffic crashes occur across space and time, conventional approaches have failed to provide alerts and insights in relation to geospatial regions, enabling proactive prevention measures. Aggregation of other data sources such as real-time weather, traffic flow counts and congestion levels etc. to alert authorities on increased crash risks is another gap that needs attention. The lack of geospatial analysis or visualization on available crash data (e.g., crash hotspots identification) limits road agencies' abilities in prioritizing funds allocation to more impactful improvements. The enforcement authorities also find it difficult to deploy their staff strength to high-risk areas. The latest advancements in programmatic geospatial analysis, interactive map visualizations and open-source software offer a unique opportunity to fill these gaps in a cost-effective way. This paper presents an application of data science and data visualization technologies to analyze road crashes. Popular packages written in Python programming language were used for the analysis. GeoPandas library provided the ability to process GPS locations (latitude and longitude) while Matplotlib was used to generate static maps. Folium library and the underlying Leaflet.js library were applied to generate interactive maps to help visualize crash hot spots. The study developed algorithms to combine GPS location data from crash records with boundary and attributes data from geospatial files to generate road crash density maps by administrative division areas and population. Interactive maps that allow authorities to drill down (or zoom in) to hot spots were also developed. Unlike GUI-driven analysis tools such as ArcGIS or QGis, the programmatic approach developed in this study enables the repeatable application of the analysis and visualization to new and old datasets with minimal effort. The application of existing geospatial analysis tools to road crash data is the key contribution of this study. The findings from the study lay the foundation for a digital system that can become an online platform for road and enforcement agencies to obtain reports and alerts on road crash risks and hot spots. The application was tested using crash data in Sri Lanka and outcomes are presented in this study. Future work such as real-time prediction of crash risk using machine learning technologies and fusion of multiple data sources onto the same platform can bridge the current gaps in crash prevention measures.
item: Conference-Abstract
Application of intelligent transport system (ITS) in passenger boarding and alighting surveys
(Department of Civil Engineering, University of Moratuwa, 2020-12) Vidanapathirana, C; Thilakshan, T; Sharic, S; Bandara, S; Perera, HLK
Bus passenger transportation essentially requires continuous planning, evaluation and upgrading to maintain its level of service. Necessary traffic data including passenger counts, bus stop locations and corresponding demand, speed, relevant functional and infrastructure information have to collect regularly by the authorities to conduct such studies. Though there exist various conventional approaches for data collection, most of them are regarded as less effective in the present context. Global Positioning System (GPS) based applications in intelligent transport systems have proven to be efficient and cost-effective in identifying and tracking the geolocation of connected elements. Hence, with the intention of narrowing the technological gap, a holistic system that embodies both hardware components and software applications were developed for real-time data acquisition with remote access. This multidisciplinary engineering solution collects data mainly from two sources. Firstly, a mobile application was developed to facilitate the collection of trip-specific data. For every journey, at the departure, the surveyor can create a new trip in the app and input the origin, destination, date, surveyor’s position (front door, back door or middle door) and characteristics of the vehicle. Then a recurring sequence of features appears on the screen to record the GPS locations of bus stops, boarding and alighting counts at every bus stop, passenger demographics and the characteristics of each bus stop. All the data are transmitted to a server in real-time for storage and remote retrieval purposes. The surveyors are provided with unique login identities to improve the credibility of the survey. Every journey is labelled with a system-generated identifier which can be changed if necessary, to facilitate conducting surveys by placing two surveyors at the front and back doors of the same bus. On such occasions, retrieval of data can be carried out corresponding to the journey ID. Secondly, a handheld portable electronic device which is capable of locating its position at regular intervals was developed with single-board computers (e.g.: Raspberry Pi), GPS receivers, data communication module and rechargeable power sources. An interactive display similar to a mobile phone is available in this device. The surveyor can input the details about each journey before the departure. When the journey begins, the automatically recognized realtime GPS coordinates and travelling speed are displayed to the user. A single-click feature to log waypoints with an accuracy of 2.5m was also provided. This serves as a facility to locate bus stops, bottlenecks, intersections, or any other parameter as expected in the survey. These data are also sent to the same server and can be visualized through the front-end user interface. This approach can be directly utilized in assisting annual fare reviews incorporating both the cost component and income component eliminating past barriers. The data helps in developing driving cycles and thus fuel consumption and other cost parameters can be identified involved in bus services. The boarding and alighting surveys reflect the income components via the collected data. Thus, the calculation for fare review revisions become relevant and reliable with a good rationale and justifiable outcome helping three stakeholders (related authorities, passengers and bus owners/employees). This can be a fair play fare platform to all involved entities. The quality and level of service of public transit can be improved using this technological introduction including route requirements, increasing or decreasing supply as per the demand, improving and altering timetables (scheduling services) and restructuring bus stop locations and level of service of bus stops/terminals with available data based on demand and usage. The results that can be tabulated in terms of data via the ITS incorporated approach can be utilized for analysis with effective outcomes. It is very important to attain the quality of data along with a considerable quantity. This approach helps in establishing healthy quality data over the conventional methodology in Passenger Boarding and Alighting Surveys. The outcomes from analysis of the available data can be utilized with a higher acceptance in inclusion for required transportation applications. The data security and storage phases provide high effectiveness in comparison to conventional technology redundant approaches. A digital platform can facilitate easy quick data retrieval without having to waste considerable time and effort. In a sustainable perspective, the inclusion of technology into the surveys and its process helps in the reduction of waste and usage of resources increasing environmentally prominent actions in terms of the survey process and outcomes. This technique is deemed the way forward of surveys in transportation engineering since it has a low margin for error unless it is a technical malfunction. With the use of highly reliable and state of the art technology, better levels of precision and accuracy can increase the validity of decision making in the industry. This approach which is initially implied to be applied in public bus transport services can be extended to other public transit forms such as railways with minor parametric changes and can be developed further into a passenger transport analytics platform.
item: Conference-Abstract
Application of sub-ballast embedded with waste rubber tyres in rail infrastructure in Sri Lanka
(Department of Civil Engineering, University of Moratuwa, 2022-12) Silva, PS; Nawagamuwa, U; Perera, HLK
Railway transportation has become one of the most popular modes for transporting freight and passengers all over the world due to factors such as increased road traffic on highways, urbanization, and population growth. Maintenance of rail tracks consumes a considerable cost. A ballast is introduced to bear loads, facilitate water drainage and prevent underlying vegetation from surfacing. While transferring the imposed loading uniformly to subgrade soil at a stress tolerable for the subgrade material, it provides the necessary degree of elasticity and resilience to absorb vibrations and shocks. However, ballast degradation is one of the major issues in the rail substructure due to excessive stresses and vibrations. Increasing the durability of the rail substructure will minimize the cost needed for maintenance and replacement. Geogrid and geocells can be placed below the ballast layer to prevent the frequent maintenance of the ballast layer. The three-dimensional cylindrical shape of the rubber tyre and the material properties match with the ground improved with geocells. Further, rubber tyre is a wasteland and cause numerous environmental and health hazards when dumped inappropriately. This research is a numerical study done with Finite Element Analysis using ABAQUS software. The traditional rail substructure, which contained the Ballast, Sub ballast, and Subgrade layers, is considered in the analysis. Proposed rubber tyres are embedded in the sub-ballast layer filled with sub-ballast material. 250kN and 350kN axle loads with the frequency of 10Hz dynamic load conditions are applied on the sleepers, considering the rail speeds in Sri Lanka. The impact of the sub-ballast embedded with filled rubber tyres subjected to cyclic loading is observed by varying the tyre sizes. Sizes of rubber tyres were selected based on the available wase quantity of such tyres in Sri Lanka. Sub-ballast embedded rubber tyre layer reduces the vertical stresses which are transferred to the subgrade, causing settlements. According to the results of the analysis, the most effective tyre size for reinforcement is 165/55R14 among the analyzed tyre sizes. The effectiveness of the tyre layer is increased with the decrease in the tyre section height. The number of rubber tyres that are needed to reinforce the 1km of rail track is also calculated in this study
item: Conference-Abstract
Applying Built – Operate - Transfer (BOT) systems for Sri Lankan expressways: a case study
(Department of Civil Engineering, University of Moratuwa, 2020-12) Perera, AP; De Silva, D; Perera, HLK
Sri Lankan transport network had a massive development during the last decade experiencing highway infrastructure, with the utilization of foreign concessions and local government funds of the country. Road Development authority holds the pioneering authority to operate and maintain the highway and expressway network in periodically. The user benefits generated with the road network are travel time saving, developed infrastructure and living standards also with the social benefits which are not counter measured in quantitatively. As a developing country, a lack of financial stability for the infrastructure of the government may lead to foreign loans and concessions. The concessions lead to rapid involvement in the fund involvement for mega infrastructure projects as the necessity and demand of the country. The Build-Operate-Transfer (BOT) concession model is becoming a major trend in the privatization of infrastructure projects and the concession period and interest rate are critical parameters for BOT contracts. In this study, a model is developed to demonstrate the potentiality of applying BOT system for the expressway network of the country. The demand estimation, operation and maintenance cost and toll revenue used as the inputs for this model and financial viability is observed with different scenarios. The concession period, interest rates and optimality of selection of BOT are decided with different criteria based on financial viability. As the Colombo-Katunayaka Expressway (CKE) meets the highest demand for traffic in the expressway network, inputs of CKE used to demonstrate the potentiality of applying BOT model and optimum subsidy level was determined with the application of variable concession periods. This BOT model is further developed to validate any expressway network in urban or suburban basis by considering traffic demand with the considerations of unit length costs and revenues in operations with the performed analysis for existing and proposed expressways in Sri Lanka The urban and sub-urban links were defined for expressways, by considering the actual traffic demands between each intersection of Outer Circular Highway (OCH), Southern Expressway and forecasted traffic on ongoing Central Expressway and proposed Ruwanpura Expressway and costs and revenue per unit length were determined for each link in respectively by applying actual data.
item: Conference-Abstract
Assessing the walk-score of walking paths in Kandy City area for better walking experience for the tourists
(Department of Civil Engineering, University of Moratuwa, 2020-12) Wijeweera, KP; Dias, TWKIM; Perera, HLK
Walking has been always considered as a sustainable method of transportation which is more suitable for short-distance trips. The concept of “short distance trip” changes with the convenient maximum walking distance of a human being. However, it is observed that tourists would prefer to walk more than residents in cities with many tourist attractions located within close proximity. The City of Kandy, in Sri Lanka, can be recognized as one good example for such cities. Even though the tourists are willing to walk longer distances, this study has assessed the walking experience of a pedestrian in the city limits of Kandy, based on a walk score. Several walkability characteristics are taken into account to generate the walk score for segments of roads in the city and Pedestrian Level of Service (PLOS) was also considered. PLOS does not have considerations for tourists, it was used only to assess the basic requirements for pedestrians. A study done by Hall and Ram in 2018 comparing TripAdvisor ratings and Walk Score found that more specific assessments of walkability are required to evaluate the tourist requirements. Considering several works of literature as such, this study used an evaluation criterion developed by Dias in 2012 to obtain the walk-score and tourism specific features such as availability of shops and ATMs were taken into account. The objective of this study was to recognize the best walking paths between the tourist attractions using these qualities. The study area was based on the tourist attractions in Kandy and the importance of walking for the tourists within the city. Data were collected through field surveys in 2018 to identify walking facilities provided and to estimate PLOS in the selected street segments. Recommendations are proposed to improve the walking experience for the tourists. Twenty-six road segments were selected for the study and the Walk-score ranged from 24% to 60% with an average of 45% which cannot be considered as a satisfactory situation. As a walk score criteria were used, there was no requirement to do an opinion survey among tourists who walk these paths. Availability of amenities for pedestrians is one factor in estimating the walk-score in which the availability of bank facilities, restaurants, shopping malls, transportation terminals (bus stops and train stations), roadside benches etc. However, the results showed the lack of such amenities in many street segments which can be discouraging tourists to choose the street segment for their route. According to the results, it is important to remove obstructions which are located in the sides of the walkway which reduce the effective walkway width creating unnecessary queues. When selecting a walking path to reach a tourist destination it is expected that they will tend to select the best walking path. Using the results of this study, a tourist can take an informed decision on choosing the best route and also the relevant authorities can prioritize the budget allocations on improving roadside facilities.
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Axle load distribution characterization for mechanistic pavement design
(Department of Civil Engineering, University of Moratuwa, 2020-12) Sumanasekara, S; Mampearachchi, W; Perera, HLK
As per the World Bank records of the year 2018, Sri Lanka had the highest road density among the South Asian countries with 173.9 km of roads per 100 square kilometres of land. Sri Lankan government reserves a considerable amount of finance in every year for developing and maintaining the existing road infrastructure, which is a well-recognized national priority. Currently, in local road designs, the Overseas Road Note 31 and AASHTO method are the most frequently used design references. However, in these methods, the consideration given for utilization of readily available in-situ materials and incorporating characteristics of substandard materials into the designs is not significant. Therefore, in most of the occasions, the economics of the construction processes are adversely affected due to overdesigns. The AASHTO Mechanistic-Empirical (M-E) method of pavement design combines the physical causes such as stresses, strains, and deflections within a pavement structure and the empirical mathematical models. It also allows the designer to utilize in-situ materials and allows to optimize the pavement design to suit the conditions at the site. Although attempts had been made to adopt M-E design method in Sri Lanka, since the M-E design process requires a lot of data input, the preference of local practitioners in using the M-E method is not satisfactory. Out of the input parameters required for M-E design, traffic volume and axle load distribution data are crucial parameters. This study aimed at identifying trends in axle load group type distributions in different regions and to establish a classification for the pavement loading in regions throughout the island. It has been found that there are similar patterns in the distribution of axle group types throughout the island. Accordingly, on average the total axle counts in different regions constitutes of 57% single axles with single tires, 38% single axles with dual tires, 5% tandem axles with dual tires, and 0.1% tri axles with dual tires. Further, in this study, hierarchical clustering techniques have been utilized to identify geographical regions with similarities in pavement loading conditions. An attempt for zoning traffic load distributions for selected geographic areas has been presented in this study. Comparative for the resource utilization in obtaining axle load distributions, obtaining manual classified counts for a road is convenient. With the aid of the identified traffic load zones, this study will be useful for determining the traffic data input for M-E design, with a degree of accuracy level 2 as defined in the M-E design method.
item: Conference-Abstract
Axle load distribution for mechanistic-empirical pavement design in Sri Lanka
(Department of Civil Engineering, University of Moratuwa, 2022-12) Sumanasekara, S; Mampearachchi, W; Perera, HLK
The AASHTO Mechanistic-Empirical (ME) method of pavement design seeks to combine physical causes such as stresses, strains, and deflections within a pavement structure and empirical mathematical models. The pavement responses under the ME method are computed using detailed traffic loading, material properties, and environmental data and are used to predict incremental damage over time. The design of pavements under the ME method is an iterative process using analysis results based on trial designs postulated by the designer. The basic advantage of the combined ME method over a purely empirical method is the ability to accurately characterize in-situ material. Hence it can be used for both existing pavement rehabilitation and new pavement construction, and also, the ME method accommodates changing load types and allows the designers to optimize the pavement designs. However, in Sri Lanka, the design references frequently used for local road designing purposes are the Overseas Road Note 31 and AASHTO method, which do not allow the designers to utilize the in-situ material characteristics in the design process in order to utilize the readily available materials effectively. Therefore, in most scenarios, the economy of road construction is affected detrimentally. Therefore attempting to adopt the ME design method in Sri Lanka is worthwhile investigating. For the pavement design using the ME method, the axle load spectrum data is required. In general, traffic volume is more convenient to obtain than load spectrum, considering the time and resource consumption in gathering data. The historical traffic counts and vehicle classifications are more likely to be available on many existing routes. However, for a new route, historical traffic data may not exist at all. Under these circumstances, it is necessary to estimate load spectra based on indirect information. Therefore, there is a need to develop default or representative axle load spectra that can be used with some level of confidence in the design process. Therefore, this research is aimed at deriving region-specific axle load spectra that will allow the generation of more appropriate inputs for pavement designs from the ME method. This study uses hierarchical clustering methodology and Euclidean distance matrix to identify geographical zones having similar characteristics in axle load frequency distributions. For single axle/ single tires axle loads, three geographical zones and for single axle/dual tires axle loads, four geographical zones have been identified for having similar characteristics in axle load frequency distributions. The axle load zones derived in this research will allow the estimation of traffic input to the ME pavement design approach from limited site-specific traffic data and will support the implementation of the ME design method in Sri Lanka.
item: Conference-Abstract
Barriers in adoption and operation of electric buses into the existing public transit network
(Department of Civil Engineering, University of Moratuwa, 2021-10) Thilakshan, T; Sugathapala, T; Bandara, S; Perera, HLK
Transportation has been identified as a major contributor in terms of increase in air pollution and related impacts resulting in climate change and global warming amongst other threats to the world and people. The nature of transportation related pollution has been caused by increasing motorization along with the absence of targeted policies especially in developing countries and frameworks for cleaner transportation options. Many types of measures to fight transportation related pollution are adopted globally including modal shift towards public transport, electrification, low-carbon fuels and energy vectors, demand management, innovation and upscaling, and improved design, operations and planning of transport systems. Electrification of vehicles has been globally accepted as a transfer of high potential due to the absence of tailpipe emission and the possibility to generate electricity from renewable energy sources has more potential to make electric vehicles cleaner in an overall context. Sustainable transportation mainly comprises of development of public transit and transfer of private vehicle users to public transit modes. It is evident that public transit is one of the most preferred sustainable options in transport but it’s contribution to the overall transport emission scenario is significant at present, especially in developing countries, due to higher model share. The use of cleaner technology in public transport can make a substantial impact on the reduction in emissions. This study concentrates on public bus services and the replacement with or introduction of electric buses which is currently being initiated globally. The adoption of electric buses (e-buses) includes its set of positive outcomes but is a challenge in the initiation and implementation process. The adoption of e-buses is not an easy transition which is impacted by a number of barriers including high initial procurement costs, issues related to charging and related infrastructure development, still relatively new/novel in terms of technology, scarcity of skilled labour, unavailability of data amongst others. The outcome from the study with respect to the barriers and the related mitigation measures to facilitate adoption and operation of electric buses is attained via a comprehensive review of the available sources published including research papers, national/non-governmental reports and relating documents which discuss on the air quality levels especially in the urban context and the contribution of the transport sector to the overall air pollution ratio. This study identifies the barriers, elaborates the reasons behind the barriers and recommends mitigation strategies to accommodate these barriers in the best possible manner to ensure transition to electric buses can be facilitated in a smooth manner with no considerable impacts to any stakeholders. The infrastructure related to electric buses operation is a major part of operating a viable electric bus network. Thus, identifying the stakeholders and the related barriers in adoption and operation of e-buses, development of effective operational strategies and development of an efficient evaluation mechanism are important parts of the e-buses framework considered in this study. The study discusses the identification of the right technology & viable business models, the framework for the development of an optimization model for electric bus operation subject to resource constraints which include planning of routes, 10 development of schedules and charging intervals in compliance with the available infrastructure. Outcomes from the study are expected to facilitate and educate operators of electric buses in the public transit network with the positioning of electric buses in the right framework so that the service can be provided with no disruptions to adoption and operation along with the prime goal of maximizing the expected outcome of the total reduction of emission and promotion of e-buses in an economically viable manner.
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Benchmarking: a tool to evaluate the performance of information and fare integration in a city
(Department of Civil Engineering, University of Moratuwa, 2021) Joshi, G; Arkatkar, S; Dawda, N; Perera, HLK
Rapid urbanization, a rise in population, and a booming economy have stimulated the growth in cities and resulted in higher dependence on private vehicles for personnel mobility. This has raised issues over the sustainability of transport infrastructure in cities. Public transportation systems (PT) can help achieve the goal of sustainable transportation, but they face tough competition from other private and informal modes of transport. Hence, to ensure sustainability, the existing transport systems, i.e., both public and private, need to re-plan their operations to complement each other. To achieve this aim, the development of multimodal transportation has emerged. Technically, a multimodal transport system (MMTS) has five levels of integration, i.e., physical, operational, institutional, information and Pricing or fare setting. Among these, the Informational and fare setting (I&F) can be achieved easily by developing a trip planner and unified fare collection system. As a result, various cities across the globe have tried to achieve I&F integration and developed trip planners. However, if we evaluate these trip planners, they have considerable variations in their features and characteristics. With this background, the present paper attempts to evaluate the performance of trip planners of twenty-six cities across the globe using benchmarking technique. For the evaluation of I&F integration, based on the detailed literature review, the checklist was designed to measure the degree of I&F integration. The checklist contained six major components, i.e., design of Trip Planner, Information available in Status Updates, Availability of Maps, fare integration, help & contact, and other information. Twenty Indian (Surat, Vadodara, Kolkata, Nasik, Nagpur, Chennai, Chandigarh, Bhopal, Bangalore, Ahmedabad, Kanpur, Prayagraj, Agra, Varanasi, Indore, Amritsar, Pune, Mumbai, Bhubaneswar, and Delhi) and six international cities (London, Singapore, Hong Kong, Paris, New York, and Munich) were evaluated. Finally, their composite information & fare performance index was obtained. To design the I&F performance index of the city, the information available in the mobile-based application was compared with the available checklist. It was observed that Indian cities lag in status updates and other information components. Further, a composite information & fare integration index for all cities was calculated (CI&FII), representing the information and fare integration level achieved in the cities. The CI&FI values of only two Indian cities, i.e., Delhi and Mumbai, were competitive with international cities while the other Indian cities were lagging. Availability of dynamic real-time information of transit stops and transit routes, development of distance-based fare structure for all the public modes of transport, and designing a definitive guide book related to I & F setting are the essential recommendations proposed to improve the MMTS of the (cities).
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Civil Engineering Research Symposium 2021 (Pre Text)
(Department of Civil Engineering, 2021) Perera, HLK
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Corridor level traffic management through variable messaging systems: a case study on east west links entering Colombo
(Department of Civil Engineering, University of Moratuwa, 2021-10) Arunakirinathan, V; Premasiri, M; De Silva, D; Matsunuma, T; Perera, HLK
Increasing traffic volumes on the major road corridors result in building up traffic congestion during the peak hours. Even in a congested road network, some route options are relatively lower congested while some are overly congested. This implies that drivers are not always wellinformed about all the route options they have, and the road network is not in a full equilibrium state. When temporary road closures, partial closures for road maintenance, etc. happen chaotic traffic congestion can be seen as drivers try to find alternative routes without proper information about traffic condition in other roads and possible delays. Drivers currently can use vehicle in-built navigational system or smart devices with navigational applications to get real time traffic information. But in a country like Sri Lanka, majority rely on their experiences rather than the digital navigational aid. Displaying the dynamic travel time information and route options using Variable Message Sign (VMS) boards as an adaptive traffic control system, is tested to be simple but highly effective by several researchers. Providing information about the real time congestion level on regular routes and possible delays will help the drivers to avoid the overloaded routes and balance the road network which will ultimately optimize the system performance. One of the key parameters to be considered while implementing an effective VMS system is identifying the locations where the signboards should be erected. These places should be determined considering the route alternatives, possible diversions, and ease of the drivers. This study looks at finding optimal locations to achieve corridor level diversions for the vehicles entering Colombo from east to west direction. The Low-level Road, High-level Road and Kaduwela Road/ Sri Jayawardenapura Mawatha (SJP) corridors are considered the main three corridors from east west direction, connecting the Outer circular expressway and Baseline Road in North-South direction. Among the three corridors SJP is one of the critical corridors where demand exceeds capacity now. A calibrated macro-model covering Western Province of Sri Lanka, was used for the analysis. Select-link-analysis were done to identify the major origin destination pairs of and the route analysis was done separately for each origin links to identify their destination zones and potential diversion volumes. 6 major locations for corridor level diversion using VMS and 7 minor locations to support the major diversion using auxiliary signage boards were identified. From each major diversion locations potential number of vehicles to divert were identified. The results show that with 30% of potential diversion vehicles directed through VMS, a 10% vehicle reduction in Rajagiriya section and 18% in Malabe could be achieved. 19 This method can be adopted to any larger corridor level diversions as well as to local diversions inside the city limits and implemented using movable or fixed VMS with real time traffic information system such as M-TRADA, (A travel time estimator using Google API)
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A data acquisition methodology for the development of local driving cycles
(Department of Civil Engineering, University of Moratuwa, 2020-12) Gajanayake, S; Bandara, S; Sugathapala, T; Perera, HLK
Driving Cycles (DCs), the time speed profiles of a certain vehicle type for a given road segment can be considered as one of the main tools to quantify and to assess the performance in terms of fuel economy and emissions of a given vehicle category. There have been numerous approaches that have been adopted to develop DCs locally, representing various geographical regions of the world. Despite various approaches adopted, the researchers have defined a four-stepped common methodology for DC development viz. Route Selection, Data Acquisition, Cycle Construction and Cycle Assessment. During the study, approaches have opted under each step pertaining to the purpose of the DC development, i.e. for the characterization of fuel economy. Acquisition of data for DC development is one of the most important steps of the procedure since the representativeness of the DC of local driving behaviour depends on the quality of the data collected. Regardless of the approach adopted, the acquired data should be reliable, representative, consistent and homogeneous. The three main approaches that are in practice throughout the world can be listed viz. chase-car method, instrumented-car method and hybrid method. During this study, more focus is concentrated on suggesting a methodology of data collection for DC development. Since local driving behaviour incorporates irregular kinematic patterns integrated with aggressive driving behaviour, the instrumented-car method has opted over the chase-car method. Moreover, the operational complexity and the cost associated with the latter approach is higher than that of the opted method. Furthermore, on par with the introduction of On-Board Diagnostics (OBD) protocol as a worldwide standard for automobiles in the later 1990s, the invention of many OBD data logging devices happened. Consequently, the data logging on an automobile has been made convenient than ever. When it’s funnelled down to the instrumented-car method, the techniques in practice can be listed under two main categories viz. device-based methods and device and app-based methods. In device-based methods, the data are saved in internal storage and then it’ll be transferred for analysis. On the other hand, the device and app-based method facilitate the real-time data to be transferred to the connected app-hosting device viz. a mobile device, tablet or a laptop. In the latter method, the data logging device is connected with the app-hosting device primarily via Bluetooth or WIFI. Car manufacturers have introduced their own OBD data logging devices with internal storage viz. Chrysler DRBIII, Ford New Generation Star Tester, General Motors Tech II, Toyota Diagnostic Tester, Nissan Consult, VAG 551, etc. The said devices have mostly been introduced with the manufacturers’ proprietary technology which has made them costlier. Due to the cost factor in the device-based method, most of the researchers have adopted device and app-based methods which have come up with low-cost alternatives. A dedicated data logging device, ELM-327 adapter has opted for the research study. Due to its lower cost and hence multiple devices can be used for parallel data collection in vehicles. Out of several third-party software applications for OBD data logging, Torque ProTM has been opted for the study mainly due to its feature-rich interface, operational convenience and compatibility with a wider range of vehicle variants. The data is sampled at a frequency of 1 Hz. The logged data onto the app-hosting device is saved in two main types i.e. ‘.csv’ file type and ‘.kml’ file type. The mechanical parameters viz. engine speed and fuel flow rate, the spatial parameters viz. latitude, longitude and altitude have been logged using the said device-app arrangement. During the study, data is planned to collect from two-wheelers (2W), three-wheelers (3W) and four-wheelers (4W). The initial phase of the study would be to analyze the data streams pertaining to 2W, 3W and 4W, then evaluate whether there are significant discrepancies among the driving behaviours and patterns. Then the second phase of data collection would be conducted to develop the local driving cycle. Unlikely in 4W, in 2W and 3W, an OBD port cannot be found in common. Thus, an app-based data acquisition method is recommended for 2W and 3W. With respect to this case, several readily available applications are tested. The major limitations of the applications are that they log data at lower frequencies such as less than 1 Hz and the operational difficulty of obtaining the logged data from the users’ devices since the real-time data logging feature is unavailable in most. Therefore, a locally developed application at the University of Moratuwa which suits the data collection requirements has opted. The sample size has been selected as thirty vehicles from each category, accounting for ninety vehicles altogether in all three types. The geography of data collection has been selected as the urban areas of Colombo City.
item: Conference-Abstract
Decision-making framework for effective trip planning based on travel time reliability
(Department of Civil Engineering, University of Moratuwa, 2021-10) Vidanapathirana, C; Bandara, S; Perera, HLK
Decision making is a key element in trip planning. As the vehicle volumes on road networks increases, the uncertainty of traffic and roadside situations grows resulting in unreliable travel times. Hence, planning a trip becomes a challenging task, especially in situations where there are alternate routes and no reliable data (i.e.: travel times, real-time traffic levels) to make sound decisions. Since a trip possesses a monetary value that can be measured in terms of time and/or cost, trip planning and related decision-making have become key aspects of contemporary transportation. Traffic data collection had been a conventional practice until the recent advances in research work introduced many technology-based automated solutions. These inventions facilitated real-time large-scale data collection and provided access to such data revolutionizing the field of transportation. The analyses conducted on travel conditions generate useful information that aids the trip planning and decision-making process. The objective of this study is to aid the users of transport systems with the trip planning process through a systematic decision-making process. The methodology of the research involves developing a data-driven decision-making framework to fulfil the said purpose. Travel time reliability which is defined as the dependability of travel times is the key parameter incorporated in the proposed framework and it is measured using indicators: the cumulative probability of arriving at the destination at the desired arrival time (primary measure), and coefficient of variation of the travel time distribution of the selected route (as a secondary measure if needed). The basis of the decision is â€˜the risk of experiencing an unpunctual arrival’ which is measured in terms of cumulative probability as stated before. The risk can be a late arrival as well as an early arrival. The outputs are generated based on the user requirements namely departure time, arrival time, and route choice. Hence, this is a user-specific (or scenario-specific) decision-making tool that produces solutions for an exact trip-making instance. In other words, this framework does not produce general solutions. This paper presents the final framework developed in this research for the decision-making process. It requires historic travel time data of road segments to determine the cumulative probability for reliability measurement. Provided that such information is available, this framework can be effectively utilized to assist the users in the decision-making process of trip planning. The latter part of the study demonstrates the applications of the proposed decisionmaking framework using several scenarios that represent different expected departure and arrival time conditions. For situations such as selection of the most suitable route for a trip from the available alternatives and determination of the most probable arrival time for a trip, this method can be applied. The outputs can assist the user to make choices rationally thereby avoiding unnecessary delays and/or losses. The outputs generated based on the proposed methodology are simple and straightforward; thus, this method can be directly adopted in the trip planning process. Even for the users with less technical knowledge and analytical skills, this framework can provide guidance to methodically arrive at a decision (e.g.: distinguishing the most suitable route and the optimum departure time for the trip, the decision on the optimum departure time based on a fixed arrival time or when there are limitations on the latest arrival time, determination 14 of a desirable arrival time based on a set departure time or when there are limitations on the earliest departure time) regarding the trip. The access to more accurate data will further improve in the future and the technological breakthroughs will pave the way for the development of a user application for day-to-day trip planning needs. The transport planners, authorities, and regulators can also benefit from this framework as it allows them to establish traffic management decisions (e.g.: identification of reliability-related high-priority links on the road network and implementing suitable traffic plans) based on the generated outputs.
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Demand-based roadside parking control strategy for a main road corridor
(Department of Civil Engineering, University of Moratuwa, 2022-12) Dissanayake, M; Gamlath, I; Bandara, S; Perera, HLK
Overcrowding in parking lots near high-demand locations is common in any main urban road, where parking demand often exceeds supply and parking spaces are distributed unevenly. This study aims to develop an effective roadside parking control methodology and strategy using the case study area of the Galle Road Corridor in Colombo, Sri Lanka. To accomplish this objective, it is necessary to identify various parking management strategies, identify parking fee methods and monitoring tools that are being used. In addition, the parking demand and supply on the selected section of the road are required. A single transportation corridor in an urban setting was studied, focusing on light and medium-duty vehicles. Instead of implementing a single uniform parking fee system for the entire region, we are proposing to implement a method where the parking fee varies based on the location and time of day so that demand can be distributed to less congested areas. Parking fees will be decided based on the above criteria. The methodology was developed using data such as parking location data and parking time data from the Colombo Municipal Council (CMC). Furthermore, the number of parking spaces was compared to what is currently being collected through Google Maps. The Galle Road section between Kollupitiya and Wellawatta was divided into 13 zones, and parking usage was analyzed by identifying demand, rush hours, and day variations of parking using CMC parking usage data. Following that, a physical survey was conducted to verify the past data that had been analyzed. The use of parking spaces during the day, as well as the vehicle type of parking vehicles, was monitored in the selected sections. Then identify, the pattern between those data and high, medium and low-demand sections was identified based on the time of the day and day of the week. Using CMC parking usage data, spot demand and parking variation by time and by day were identified. High parking was observed between 12.30 pm and 1.30 pm and 6.30 pm to 7.00 pm in the section from Pentrive Gardens to 5th Lane, as well as excess parking in the Alfred House Gardens to Bagathale Road section. As a result, pricing mechanisms can be used to distribute parking. The parking price and parking arrangements were adjusted according to the demand of the location. As a result of these changes, a new smart strategy for managing public parking in urban areas, such as a mobile app and features, was suggested, allowing for more efficient use of parking spaces in the city.