Browsing by Author "Sirisoma, RMNT"

Now showing 1 - 7 of 7

item: Conference-Extended-Abstract
Development of a methodology for bus route network analysis for the western province
(2002) Sirisoma, RMNT; Bandara, JMSJ; Kumarage, A
The selection of an optimal public transport route structure for a transit network is a combinatorial type optimization problem. Therefore finding a good solution would not be based on theoretical network analysis methodologies. All passengers would prefer to have a direct route connecting each node pair so that it will reduce their travel cost and transfer cost. Then the level of service will also increase. On the other hand, it will increase the operator cost. Further, the demand between some of the node pairs will be very low and a direct bus route cannot be justified. The operator would always prefer to operate on a route with a higher demand and higher income. Therefore, there should be a compromise between these two situations. The optimum solution should be found that satisfies both parties. Design of such a route network cannot be done manually due to the complexity of the road network and the demand distribution pattern.
item: Conference-Abstract
Formulation of a rapid transit route network for Colombo
(Department of Civil Engineering, University of Moratuwa., 2016-08) Devasurendra, KW; De Silva, GLDI; Sirisoma, RMNT; Bandara, JMSJ; Pasindu, HR
Colombo, as many major cities in the world with a growing population and an expanding economy, is facing the challenge of meeting the demands of increasing mobility needs within the city in terms of quantity and quality. Over the past few decades, land transport in Colombo has evolved in to traffic clogged roads especially during the peak hours making access and mobility between households, work places and other important locations a time consuming and a tiring task. Therefore, improving the mobility and accessibility in the inner core of the city, has become one of the major requirement of the country. A review of literature for the possible interventions suggested that an elevated mode of rapid transit is the best due to the unavailability and high costs of lands in this area. The other supporting reasons for such a system are the comfort, ease of access, less obstruction for the existing road traffic and hence low travel time between origins and destinations. Therefore an elevated system is likely to attract more private vehicle users, provide more options for public transport commuters and reduce road traffic congestion while improving the accessibility and mobility. Formulating the most effective and efficient route network to solve the mobility issue is therefore at utmost importance. The access locations of the rapid transit system which is the most important component of the network, were identified with due regards to the major trip generation points (Residential areas, apartment buildings and etc.) and major trip attraction points (office complexes, schools, recreational facilities, transport nodes, super markets and public places like hospitals and etc.). Possible major stations (nodes) were selected within the walking distance (500m) of majority of these trip attraction and generation points considering the land availability and security reasons as well. The routes were identified through minimum spanning tree process in order to minimize the cost of construction by minimizing the total length required to cover the identified locations and by taking the difficulty of construction (sharp bends and etc.) and required land acquisition in to account. Possible connections between the nodes along the existing roads that are possible to connect were identified with their distances. All these links were converted to equivalent cost figures which has taken the length, difficulty of construction and required land acquisitions in to account. A cost matrix was then formed between the nodes. In order for the cost to be a minimum, these nodes have to be connected with the links with minimum possible costs. Therefore, the minimum spanning tree method was utilized to connect the nodes. Using the cost matrix, a minimum spanning tree was developed to connect the identified nodes (possible RTS stations). From the developed minimum spanning tree network, the RTS network was derived while giving due attention to the construction and operational aspects. Special attention was given to the possibility of creating loops and connecting links with other available transport modes such as railway and bus transport.
item: Conference-Extended-Abstract
Impact of performance based navigation (PBN) technology on air navigational activities at Bandaranaike International Airport Sri Lanka
(Sri Lanka Society of Transport and Logistics, 2017-07) Dayawansha, SKNM; Sirisoma, RMNT; Gunaruwan, TL
item: Conference-Abstract
It based evacuation methodology for a coastal railway system under a tsunami warning
(Department of Civil Engineering, 2011-07) Sirisoma, RMNT; Wirasinghe, SC; Pasindu, HR
Natural disasters have been known to humans ever since the formation of early civilizations. However, as increased human interventions contribute to the destabilization of the natural balance of environmental processes, even more frequent occurrence of natural calamities are occurring today. Prediction, prevention and planning/installing, detection/warning systems are very important components before a disaster. The evacuation procedure should start only once the tsunami arrival information is confirmed. Since Sri Lankan coastal railway lines typically do not have branch lines running inland, trains cannot be detoured during the evacuation procedure. Thus, the in-line evacuation process should be well planned and guidelines made known to the operator and the users. In this study, the South-West coastal railway line in Sri Lanka is analysed to identify the operation & evacuation of trains under a tsunami warning. The "safe" railway stations are identified depending on the station elevation with respect to the mean sea level, the capacity to store trains, and the number of tracks. It is assumed that, at a minimum, the railway control centre can be equipped to detect, and communicate with, all the trains and stations along the coastal line at any instance. The nearest "safe" and "unsafe" railway stations for each train, and the travel time to them, are determined with respect to the location and direction of each train atthe warning time. Travel times to each station are analysed depending on the distance and possible speed of a train. If there is sufficient time, trains are directed to a safe station; otherwise, to an unsafe station. If a train is sent to an unsafe station, passengers must be evacuated immediately. Short notice of a tsunami may also require evacuation of passengers at the nearest possible safe evacuation location, due to lack of time to reach any railway station. A methodology is proposed to identify the operational control of trains under different tsunami warning times, wave heights and locations of trains relative to stations. The confusion and concern that will prevail among passengers is considered. The poor communication and signal systems in place are considered. Planning guidelines are proposed to improve communication, select safe stations under various tsunami scenarios, as well as select evacuation stations. A procedure for assigning trains to safe or evacuation stations is also advanced.
item: Conference-Abstract
A methodology to develop a demand model for school trips in Western Province
(Department of Civil Engineering, University of Moratuwa., 2019-09) Damsara, KDP; De Silva, GLDI; Sirisoma, RMNT; Pasindu, HR
School trip is defined as a trip generated from a household or a hostel premises and ends at an educational institution (school) or vice versa. Origin-destination data is important to understand the travel patterns and also to estimate the future travel demand on transportation network over a particular catchment area. According to the administrative system of education, Sri Lanka consists of 25 districts which has 98 number of education zones having 312 education divisions. There are 10,194 total number of functioning government schools (National schools - 3.5%, Provincial schools – 96.5%) in Sri Lanka which have been categorized into 1AB – Schools having advanced level Science stream classes (1,029), 1C – Schools having advanced level Arts and/or Commerce stream but no Science stream (1,818), Type 2 - Schools having classes only up to grade 11 (3,288), Type 3 – Schools having classes up to grade 8 (4,059). Total school children population of the country is 4,165,964 and it has been divided among those 4 school categories as 1AB - 40%, 1C – 25%, Type 2 – 19%, Type 3 – 16%. Western province consists of 1,359 number of functioning government schools (965,113 students) in 3 districts which has 11 education zones and 38 education divisions. This study is focused on school trips, where the destination schools are located in western province. List of schools located in western province (as destination) is available in data management portal maintained by the Data Management Branch of Ministry of Education. Currently there is an ongoing project named as NEMIS-SIS (Student Information System of the National Education Management System) which collects data related to students who are currently enrolled in Sri Lankan Government schools. From that, origin city/town of the students which is required anonymously for this study can be collected. Based on those data Origin-Destination matrix can be prepared and a strong sample which covers all four types of schools discussed above can be selected. When selecting the sample, it is important to consider about the number of students and the number of teachers available in the school as well as whether the school is a boy school/girls school or mixed school. In Sri Lankan contest, travel patterns of school children depend on various variables such as school type, distance from home, access to transport, cost of travel etc. Therefore identification of origin-destination patterns and their relationship to those variables are used to develop a school trip demand model.
item: Thesis-Abstract
The Study of the development of bus routing plan for the Western province
Sirisoma, RMNT; Bandara, JMSJ
Effective design of transit routes and service frequencies can decrease the overall cost of providing transit services, which generally comprises passenger costs and operator costs. Usually route design is done with route scheduling and efficiency of the service is significantly depends on the route network. However, the route design problem is not straightforward due to its multi-objective nature, non-linearity and non-convexity of the objective function. The relation of the constraints and decision variables to the objective function are non-linear. Non-convexities are illustrated by the fact that more buses can be deployed without decreasing total travel time by changing the route length. Non-availability of reliable passenger demand data is another constraint. At the first stage of this study, primary bus routes that operate between Divisional Secretariats Divisions were considered. Primary route network was developed based on the passenger demand distribution in the existing system. An algorithm was developed to generate the route network with the condition that all nodes (zone centroids) have to be served at least by one bus route. In this algorithm, the maximum demand O-D pair in the demand matrix is considered first. Routes were assigned along the minimum path between those two zones assuming all the passengers would select the shortest travel path. Any inter-zonal travel demand between zones that falls within the route under consideration is also added to this route and taken off from the demand matrix. After generating the primary network, user is given the choice to fine-tune the network by using a set of algorithms for route merging, adding links and route sprouting. Fleet requirement, passenger transfers saving after each modification, revenue and operating costs per bus trip were calculated to evaluate route network. To determine the passenger demand distribution, an Origin-Destination matrix was developed based on bus passenger interviews and available socio-economic information. Passenger demand distribution over the study area was obtained based on a model calibrated using household & roadside interview data and travel costs between node pairs in the selected zones. It can be seen that most of the existing routes are operating in the high demand corridors. But there are new routes to be introduced to newly developed zones in the study area
item: Conference-Abstract
Traffic impacts at Dehiwala flyover on level of service of the intersection: case study
(Department of Civil Engineering, University of Moratuwa., 2016-08) Paulusz, NN; Sirisoma, RMNT; Pasindu, HR
Delay is the principal measure of level of transportation service at a signalized intersection. It was discovered that Dehiwala intersection has being over burdened with newly constructed flyover resulting in traffic delay problems. In addition to designing appropriate access for new developments, it is vital to maintain a satisfactory level of service. Therefore, this traffic impact study will be helpful to determine the need for any improvement. Data were collected through direct field surveys (delay survey, speed survey, classified traffic counts, Queue length survey, Pedestrian counts and Bus circulation survey) under mixed traffic operations and poor lane discipline prevailing at Dehiwala intersection. It was found that traffic congestion occurs at the intersection from 8.00 a.m. to 9.00 a.m. During this period the overall efficiency of the intersection is unacceptable. Queue formation of buses at the far side bus stop towards Colombo reaches 20 buses during the peak blocking the entire intersection. The adverse impacts which causes delay are long queues which form along Galle main road (A2) in both directions thereby vehicles entering the intersection from Galle side and Colombo side waste time in queues. Reduction in approach speeds at all four approaches were observed during the study period. After collecting data on queue formation, waiting time for buses, traffic flow, delay for vehicles and average speed, it was observed that there is no advantage of installation of flyover at the location. Observed average speed on Galle Road during the peak period is around 8 km/h having the flyover with two lanes in the same direction. Compared to the delay of vehicles, calculated Level of Services of Four approaches Hills Street, Galle Road towards Galle, Station Road are in under category „D‟ and the Galle Road towards Colombo is under category of „E‟. Considering factors which contribute to above impacts, measures such as relocation of far side bus stops, area traffic management plan, expedite the extension of Marine Drive up to Dehiwela are recommended to overcome traffic congestion and allow the intersection to maintain a satisfactory level of service.