TRF - 2012
Permanent URI for this collectionhttp://192.248.9.226/handle/123/17949
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Browsing TRF - 2012 by Author "Bandara, JMSJ"
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- item: Conference-AbstractDevelopment of a methodology to identify the critical locations and suitable roads to conduct road safety audit(Department of Civil Engineering, University of Moratuwa., 2012-07) Warnakulasuriya, PM; Bandara, JMSJ; Pasindu, HRRoad Safety Audit (RSA) can be conducted on new road projects, road improvement projects and existing roads. It is a formal process using a defined procedure and it should be performed by a group of auditors with appropriate experience and training. The audit process provides, at regular intervals, for independent safety assessments and recommendations. Road Safety Audits assess the operation of a road, focusing on road safety for all road users, including pedestrians (along with children, elderly and disabled) and cyclists. The outcome of road safety audit is an Audit/Survey Report, which identifies potential or existing road safety deficiencies and makes recommendations aimed at removing or reducing those deficiencies. There are several Guidelines & checklists for Road Safety Audits developed by organizations such as U. S. Department of Transportation, Asian Development Bank (ADB), National Roads Authority Ireland and other developed countries. Guidelines for Road Safety Audit have developed for the Road Development Authority (RDA) to be used for RDA roads as well as for other organizations responsible for their roads in Sri Lanka by SweRoad in association with RDC, as a part of the consultancy services in the Road Safety Component (RSC) of the Southern Transport Development Project (STDP) in 2005. There are 12,020 km of Class A & B roads in Sri Lankan road network under the responsibility of the Road Development Authority (RDA). Out of that, about 4,500 km length have recently improved or rehabilitated. In addition, there are over 75,000 kms of other roads under the responsibility of Provincial RDA (PRDA) or other Local Government Authorities. To conduct a RSA as per the guidelines developed for Sri Lankan roads, the relevant Road Authority shall give this task to a group of auditors with appropriate experience and training. Also at some locations, the occurrence of an accident depends on the time of the day and also depends on the day of the week. To conduct RSA by a group of auditors with appropriate experience and training for all these roads on regular basis are very difficult and expensive. Therefore, the Purpose of this study is to develop a simplified methodology to identify the critical locations to be selected for RSA and also to identify the critical time & day to conduct such RSA. This study is limited only for the existing roads in Sri Lanka. It is intend to develop simplified formats to collect data for different types of road sections & intersections by different observers. It is also intend to develop a points system to identify the critical road sections & intersections using the collected data by the different observers in order to conduct detail RSA by group of auditors with appropriate experience and training. Using the points system the relevant Road Authority can prioritize the RSA schedule for their roads and can identify the most critical roads, road sections or intersections for next RSA.
- item: Conference-AbstractDevelopment of driving cycle for Sri Lanka(Department of Civil Engineering, University of Moratuwa., 2012-07) Gamalath, I; Fernando, C; Galgamuwa, U; Perera, L; Bandara, JMSJ; Pasindu, HRA driving cycle is a speed time profile which represents the driving characteristics of a selected area. This can be of use to legislative and non legislative purposes such as development of emission standard, determination of fuel consumption, etc. Established driving cycles such as European driving cycle and United States driving cycles cannot be used in Sri Lankan context as the traffic constituents, driver behaviour and road conditions vary significantly that from the conditions of those countries. Hence the objective of this research is to develop a standard driving cycle(s) which represent urban and rural conditions in Sri Lanka and to establish emission standards in future based on such cycle(s). To achieve stated objectives, it is necessary to collect and analyse on road speed-time data on a selected route which will represent the typical driving pattern of an urban or rural condition. Due the restriction of time and resources, this study was limited to development of driving cycle for urban condition and for light duty vehicles. However, this study would facilitate further studies on this area and development of driving cycles for urban, sub urban, rural and express way conditions and this could be of great use for traffic engineering studies, road safety and sustainable development. A sample driving cycle was developed based on the time series data collected on the Galle Road, section from Katubedda to Fort. Due to the time constraint, on board method was used to collect data using a hand held GPS device. More than 30 samples were collected in this section during different times of the day and different days of the week to represent many prevailing traffic conditions at this urban road section.
- item: Conference-AbstractDynamic travel time discoverer (DTTD) collaboration with intelligent transportation systems(Department of Civil Engineering, University of Moratuwa., 2012-07) Pilanavithana, U; Bandara, JMSJ; Pasindu, HRAccurate real-time information provision and short-term predictions of traffic parameters such as volumes, travel speeds and occupancies, is a research topic that has attracted considerable interest in the literature. This is, at least in part, a result of the increasing penetration of Intelligent Transportation Systems (ITS) technologies in everyday life. ITS technologies, with Advanced Traveller Information Systems (ATIS) and Advanced Traffic Management Systems (ATMS) as examples, attempt to deal with the traffic congestion and travel time problems facing commuters in many urban areas worldwide by better synchronizing traffic signals and by assisting drivers on selecting routes based on accurate real-time information on traffic conditions. Objective of this research was to evaluate the Dynamic Travel Time and Modify the Origin- Destination Flows with latest traffic flow data obtained from minimal number of link counts within the network. Methodology in satisfying the research objective has been developed by a Dynamic Program (Dynamic Travel Time Discoverer - DTTD) to collaborate with analytical software widely used around the world. Methodology was developed to estimate the link flows and calculate the Travel Time while giving opportunity to modify the Origin Destination (O-D) Flows according to the latest information. During the dynamic programming, O-D and Flow matrices are read by the program and calculate the total link volumes according to the above matrices and store in arrays. Secondly, developed Akçelik Speed-Flow model uses to convert total flow values into Travel Time values and case studies have been carried out to validate this model to Sri Lankan conditions. This model produces significantly improved traffic assignment run times and provides more accurate speed estimates which lead accurate travel times to assure the objective of identify the best path based on travel time using minimum real time information available. As an another option, program enables user to modify the link flow values with latest traffic data from minimal number of link counts and re-write the Base Flow matrix with the updated values. When the program re-runs, it concludes the shortest path in travel time basis with the latest updates. In Conclusion, the estimation of link flows and modifying the O - D flows can be performed by two stages modal and travel time projected by the improved speed flow relationship. Projected travel time facilitates the selecting best path or the alternative for the user destination. Furthermore, integrate a method which will automatically update the system data base with the latest traffic data corresponding to road links and give the most up-to-date best travel time path to the road user is proposed as future development.
- item: Conference-AbstractThe estimation of saturation flow and passenger car units (PCU) at traffic signals for Sri Lankan conditions(Department of Civil Engineering, University of Moratuwa., 2012-07) Kularathna, UKMK; Bandara, JMSJ; Pasindu, HRSaturation flow rate is the equivalent hourly flow rate at which previously queued vehicles can traverse an intersection approach under prevailing conditions, assuming that the green signal is available at all times and no lost times are experienced, in vehicles per hour of green or vehicles per hour of green per lane. The saturation flow on an approach to a traffic signal are very important inputs to methods of estimating delay-minimizing or capacity maximizing signal settings. Procedures for signalized intersection analysis often recommend the use of measured saturation flow rates. However, it is impractical to measure prevailing saturation flow rate for an existing site and it is impossible to measure saturation flow rate for a new signal installation which is yet to be constructed. Hence, the development of a saturation prediction formula based on passenger car equivalents values derived according to local traffic conditions is necessary in order to estimate saturation flow rates accurately at signalized intersections. Passenger Car Units (PCU) are used to represent the varying effects of mixed vehicle types on saturation flows by converting a traffic stream comprising of various vehicle types into an equivalent traffic stream comprising entirely of passenger cars. It has been proved that PCU values have a significant impact on the estimation of saturation flows especially in the presence of high percentage of motorcycles & three wheelers in the traffic stream. PCU values used in Sri Lanka has not updated for a long period of time, but the traffic compositions in roads has changed significantly during recent past, therefore these PCU values are no longer accurate. Hence, the main goal of this research is to derive the basic saturation flow values of signalized intersections which is suitable for Sri Lankan conditions. The secondary goal is to update present PCU values of the traffic stream at the signalized intersections. The data collection is being presently continued in order to obtained set of more than 2500 data in the selected traffic signals in the city of Colombo, It has now been completed only the collection of about 500 data in two traffic signalized locations. At present Sri Lankan used saturation flow rate of 1850 pcu/hour which is derived in developed countries. According to the research, this value may differ significantly, and it is about 2000 pcu/hour at the end of analysis of about 500 data. The PCU values which are presently being used in Traffic Signal Design are derived for Multi-Lane roads by Transportation Engineering Division of University of Moratuwa. At the end of analysis of 500 data, it is shown that PCU values are slightly change to these values except that of Three wheelers. The PCU value of three wheelers has changed significantly from 0.8 to 1.3.
- item: Conference-AbstractFeatures and variables of quantifiable measures to be used in quantifying walkability(Department of Civil Engineering, University of Moratuwa., 2012-07) Hewawasam, C; Bandara, JMSJ; Wirasinghe, SC; Pasindu, HRPedestrian facilities in an urban area have a significant influence on the traffic flow and socio- economic environment. Walking is considered as the most efficient mode of transport for shorter distance; it is environmentally friendly, requires minimal energy, has no direct financial cost and is accessible to all irrespective of age, gender and ability if facilities are provided appropriately. Communities with good pedestrian facilities will enhance the quality of life of the people. Measure of “walkability” has been used to evaluate pedestrian facilities. Majority of such measures are qualitative in nature and rank road segments based on the level of service concept. A recent attempt to develop a scorecard based on measurable aspects of walkability is available but it focuses only on comparing roads based on the facilities available for pedestrians. However, walkability is not only about pedestrian infrastructure and it has more elements while pedestrian infrastructure being one of them. In this research four main elements of walkability have been identified as infrastructure, destination, journey and environment. A complete walkability evaluation criterion must address all these four elements. Hence with those four elements of walkability, a through literature review on the walkability models so far developed has been carried out in order to identify quantifiable measures of walkability. A set of six quantifiable measures of walkability have been identified as connectivity, proximity, density, infrastructure, land use and environmental and safety. Finally, the features and variables of those identified measures have been identified and offers in this paper to be further reviewed. It is expected to use these measures in developing a model to prioritize pedestrian facility requirements in an urban area.
- item: Conference-AbstractSimplified guideline for road markings and placement of road signs(Department of Civil Engineering, University of Moratuwa., 2012-07) Prematilake, AA; Bandara, JMSJ; Pasindu, HRMinistry of Prots & Highways and the Road Development Authority (RDA) have been focusing attention to introduce a Revised manual for Traffic Signs and Markings which is in conformity with the stipulations given in the Vienna Convention. As a result, Revised Regulations are in the threshold of publishing as an Act passed in the Parliament in near future. This will replace the Regulations which are currently in use. A Manual on Traffic Control Devices has already been prepared for the use after the Revised Act come into effect. This manual itself says that the traffic sign and road marking numbering system developed for this manual is entirely different to the numbering system which is currently in practice. Therefore, it can be expected that some difficulties may arise when this new system is implemented. In some selected newly rehabilitated roads, new Traffic control signs and markings have been used by RDA on trial basis. Current practice for marking road centerlines and placing of danger warning signs is based on the Regulations of Gazette Notification No.444/18 published on 13th March 1987. No simplified guideline has been developed so far to use with these regulations. As a result, marked centerlines and fixed warning signs in roads show remarkable deficiencies in practice. When examining different roads, it is clear that methods practiced are highly subjective. Changing marked centerlines on roads time to time to do trials can be commonly seen. The paper present an attempt to prepare simplified guidelines to mark road centerlines and placing of danger warning signs based on the proposed revised Act which is in the threshold of publishing. “ The Manual on Traffic Control Devices” would fill the gap between the proposed revised Act and the knowledge of practitioners to some extent. But, when examining the roads used for try out the new method, it is clear that still there are some practical deficiencies. The reason may be the fact that the manual discussed only the individual situations. In combined situation this manual does not give sufficient guidance. As examples, the manual discuss about single horizontal curve and single vertical curve individually. But it does not give any guidance on reverse curves and combination of horizontal and vertical curves. This paper address this type of complex situations in depth and proposes to have a simplified methods to practice. This is done by carefully studying existing conflicts and shortcomings in the current practice and in the newly proposed method and by proposing ways and means to overcome these identified shortcomings using experience of current method
- item: Conference-AbstractStrategy to identify optimum travel routes for improvements in an urban area(Department of Civil Engineering, University of Moratuwa., 2012-07) Rajapaksha, RPGKS; Perera, L; Bandara, JMSJ; Pasindu, HRTransportation is a basic requirement in any city in the world for its economic, social and other developments. Different cities in the world use various means of transportation to achieve their goals and objectives. In general, minimum travel time, comfort and safety can be considered as primary objectives of any cities transport plan. In urban cities, it’s a well-known fact that transport planning is imperative to achieve its day to day and long term goals. Congestion is very commonly seen condition in most of the urban areas in the world and there is no exception for Sri Lanka as well. In an urban context, users may have various origins and destinations in their travel needs varying over the time. These needs may have primarily arisen due to the land use mix or social desires. However, it is transport planners duty to full fill these transportation needs of users effectively under given circumstances. In that aspect identification of high demanding origins and destinations are very important and recognizing minimum distance or minimum travel time routes are critical. Proper information or planning system would direct users effectively and could able to cut off unnecessary congestion significantly. Thus, this study will explain a strategy to identify travel routes in urban area with respect to time and distance variables, where improvements can be done to reduce congestion effectively. Identification of prominent OD pairs, traffic flow conditions and capacities at different corridors, travel distances between OD’s, travel time between OD’s and most preferred routes by users can be considered as main inputs in this nature of study. Colombo city was selected as a case study and Origin-Destination (OD) surveys were carried out at number of selected locations along with traffic flow counts, taken at main and sub corridors connecting to Colombo city. Based on the OD survey analysis, prominent origins and destinations were recognized and travel time between each and every combination of origin and destination were measured multiple times, in peak and off peak conditions. Based on the collected data minimum travel time between OD’s and minimum travel time route were identified. Using the Arc GIS software, a road network plan was developed and minimum distance routes were identified between OD’s. Further, there are instances where users use completely or slightly different routes to reach their destinations other than mentioned above and thus those routes were also recognized as commonly used routes to see what deviates from the minimum distance or minimum time path. Comparison of three different routes obtained from the study revealed many problems and counter measures were given to improve the efficiency of existing conditions cost effectively.
- item: Conference-AbstractStudy the variation of visibility of road marking with time due to traffic in urban national roads in Sri Lanka(Department of Civil Engineering, University of Moratuwa., 2012-07) Sumendra, MAP; Bandara, JMSJ; Pasindu, HRIt has long been recognized that visibility of road marking is essential for efficient traffic flow and road safety. There are complaints of that the road marking in many national road of Sri Lanka have poor visibility in daytime and nighttime. The major reason for the poor visibility is low reflection levels of road markings. The performance of the road marking is affected due to embedment of glass beads, water on road way, drivers eyesight ,position and quality of headlamps, road surface debris etc. Retro-reflectivity is the ability of a road marking to reflect light from a vehicles head lights to the driving position of a vehicle. It will be determined by the amount of glass beads spread on the line and amount and quality of glass beads included in the body of road marking. Main objective of this research is to understand the variation of visibility of road marking with time due to traffic and other environmental parameters, identify the optimum frequency of time for remarking in urban roads and introduce a guide line for remarking of road marking while integrating as a program to a road database in highway management tool as a future implementation. Preliminary measurement carried at some high volume traffic roads in western province that considerable amount of reduction of reflectivity with time due to traffic. For example Galle road (A002) that has ADT of 77450 the reflectivity has changed by 46% after 9 months. Base line road (M001) has ADT of 90645 the reflectivity has changed by 62% after 6 months. Kollupitiya -Sri Jayawardanapura road (A000) has ADT of 79490 the reflectivity has changed by 69% after 12 months. The rate of reduction of reflectivity (RL per day) for Galle road (A002), Base line road (M001) and Sri Jayawardanapura road (A000) are 0.24, 0.48 and 0.26 per day respectively. IS EN 1436 and SLS 1384 introduces specifying criteria for yellow and white road markings .In IS EN 1436 the retro reflectivity value is given as 100mcd/m2 / lux for dry white road markings and in SLS 1384 this value is given as 70mcd/m2 / lux. A relationship between the reduction of reflectivity and traffic and road environment parameters to be developed based on the reflectivity measurements.