• Journal of Korean Society for Quality Management
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• v.46 no.4
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• pp.899-910
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• 2018

Purpose: Generally, since the population density is lower in suburban areas, the distance to school is inevitably long. Therefore, schools in suburban areas often operate school buses to improve student welfare. However, since school buses are usually used only during going to and from school, the utilization rates are relatively low. Therefore, this study aims to establish integrated operation plan of public school bus covering all schools. Methods: It is necessary to decide which school buses will serve the specific demand node which want to go to certain school in order to design an integrated operation plan for school buses. Therefore, a mathematical model is developed for minimizing the total number of vehicles and the distance of transportation by reflecting the characteristics of school buses and students as constraints. To solve the proposed mathematical model, CPLEX, a commercial solver, is applied. Results: To validate and to confirm the proposed process, numerical example is designed with the comparison between before and after integrated operations of school buses in terms of total operation cost. The result shows that the integrated operation can lead the reduction of the number of school buses as well as the decreasing of the fuel cost. Conclusion: This study provides the quantitative method to perform the integrated operation of school buses in suburban areas. The optimal operation strategy is required because there are more complex decision-making elements considering the integrated operation. It is expected to apply this research result at real situation to expand this services based on an optimal operation.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.5D
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• pp.617-625
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• 2008

In low-density areas where travel pattern is widely dispersed and travel demand is relatively low, transit operators find it very difficult to provide a reasonable level of service at a reasonable cost. Timed-transfer system or network, if designed properly, can provide a reasonable level of service for passengers using transit systems serving low-density areas. The paper intends to apply a timed-transfer system for bus lines serving Yangsan City area and to assess the effects resulted from the application. The concept of a timed-transfer network/system is briefly described, and the present conditions of bus systems in Yangsan City area are discussed, focusing on the aspects of network type and the related problems. The bus timed-transfer network for the area is then developed by adjusting the existing routes and network with the consideration of travel time, route alignments, headways and transfer centers. One must note that developing a timed-transfer network presumes that network and schedule should be developed together. The effects of the developed time-transfer system on the passengers and operators are found substantially so as to justify its introduction to the City. The results of this study will be of considerable use for planners to design the transit systems in low density areas, where in general travel activities are widely dispersed and travel demands are low, so that provision of good quality of transit services are difficult.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.1
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• pp.85-91
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• 2021

In contrast to standard train tracks, tramlines are often set along public roads, with trams running among pedestrians and other vehicles. In some cities and towns, trams and buses share the same routes and stations. Under the current investment appraisal system, trams are classified into light rail when predicting traffic demand and calculating benefits, but in the case of non-capital areas, it is notable that the origin-destination and transit lines of buses are not provided in the Korea Transport Database distribution data. Due to this problem, it is difficult to reflect proper mode changing behaviors between route buses and trams. This study examines the impact on tramlines of bus routes that are not currently considered in non-capital areas. Following an analysis of the effect of tram projects according to whether bus routes are considered or not, an improvement in methodology is proposed. Through this study, it is expected that the investment appraisal system for the planning of new tramlines will be improved in the future.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.1D
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• pp.25-32
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• 2009

Currently, various types of TDM (Transportation Demand Management) policies are being studied and implemented in an attempt to overcome the limitations of supply oriented policies. In this context, this paper addressed issues of effectiveness and possible domestic implementation of the HOT lane. The possible site of implementation selected for this simulation study is part of the Kyung-bu freeway, where a dedicated bus lane is currently being operated. Minimum length of distance required in between interchanges and access points of the HOT lane for vehicles to safely enter and exit the lane, and traffic management policies for effectively managing the weaving traffic trying to enter and exit the HOT lane were presented. A 5.2km section of freeway from Ki-heuing IC to Suwon IC and a 8.3km section from Hak-uei JC to Pan-gyo JC have been selected as possible sites of implementation for the HOT lane, in which congestion occurs regularly due to the high level of travel demand. VISSIM simulation program has been used to analyze the effects of the HOT lane under the assumption that one-lane HOT lane has been put into operation in these sections and that the lane change rate were in between 5% to 30%. The results of each possible scenario have proven that overall travel speed on the general lanes have increased as well by 1.57~2.62km/h after the implementation of the HOT lane. It is meaningful that this study could serve as a basic reference data for possible follow-up studies on the HOT lane as one effective method of TDM policies. Considering that the bus travel rate would continue increase and assuming the improvement in travel speed on general lanes, similar case study can be implemented where gaps between buses on bus lane are available, as a possible alternative of efficient bus lane management policies.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.6D
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• pp.571-577
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• 2012

Recently, improving public transport service at disabled people has emerged as a social issue in rural areas. By improving expensive and inefficient existing operating system, the rural bus have to change a personalized service. Under these circumstances, government and local governments are promoting the introduction of DRT(Demand response transport). DRT system is intended to promote the user's convenience. But, until now, in-depth research on the operating costs for the introduction of DRT is not well known. This study aims to look at changes in number of vehicle and operating costs before and after introduction of DRT. The results are as follows. Even though introducing DRT, total number of vehicles increases because it does not reduce the existing number of vehicles. And this study estimated to about 5 to 12 percent of the increase in the operating cost comparing before introduction of DRT. Therefore, The introduction of DRT in rural areas is a need to set the exact purpose as promote transportation convenience or cost efficiency.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.3
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• pp.371-377
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• 2022

Urban rails and buses are representative public transit systems that not only cooperate with each other, but also compete with each other. In other words, there is a possibility that the overall demand for public transportation may increase due to the introduction of a competitive public transportation system, or there is a possibility that demand will be maintained at the level that is simply converted to a competitive system. The objective of this study is to analyze the change in public transit flow when an additional transit system is introduced in a city with alternative public transit systems. To carry out this objective, we analyzed changes in public transit passenger flow before and after the introduction of an urban rail transit line 3 in Daegu Metropolitan City, where two public transit systems, urban rail and bus, exist. For accurate analysis, big data collected by passenger transportation cards were utilized for one week in the second week of April 2015, 2016, and 2019. From the analysis, it was found that although the urban rail passenger flow increased due to the additional urban rail transit system, the change in the overall public transit passenger flow in the city was insignificant. In other words, it is interpreted that the bus transit passengers have been shifted to the urban transit systems. Based on the results, this study suggested various policies to increase the demand for public transit rather than simply adding public transit systems.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.745-752
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• 2011

Light Rail Vehicle(LRT) is "New Transit System" that has transportation capacity as well as physical size of vehicle is in-between bus and subway. The demand of LRT system is increasing rapidly; both domestically and internationally. Reason being is that it is more economical and eco-friendly compare to existing heavy rail vehicle. Especially, Busan Subway Line 4 K-AGT (Rubber-tired LRT) being the first of its kind to start revenue service in Korea, it is very much likely that application of its demand will continue to increase. Considering its trend, study to reduce implementation cost of LRT is being pursued in many different aspects; reducing construction cost is one that aspect. In this study, on-site application of 'Up-Down Turnout System' implementation research has been carried out which can replace existing 'Left-Right Turnout System'. When safety of its type gets verified, application of this system to line which intends to use K-AGT, Shin-Lim Line and Dong-Book Line, expects to save its construction cost. This thesis paper reports ongoing research of AGT 'Up-Down Turnout System' development and main component design factors, fundamental principle, performance test result.

• Journal of Korean Society of Transportation
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• v.14 no.1
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• pp.7-27
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• 1996

It is very costly to construct transportation facilities such as roads, bridges, tunnels, and public parking lots mainly because land price is very high in metropolis like Seoul. Private car oweners use these facilities more extensively than public transportation users. However, the government does not impose proper charges for using these facilities. Such improper charge causes traffic congestion and then decreases social welfare in efficiency and equity. To solve problem, many traffic demand management policies are used. Traffic management policies which are currently used or under consideration by the City Government of Seoul include the imposition of road tolls, increase of parking fees in public parking lots, increase of gasoline taxes, expanded implementation of bus only lanes, and shippujae, which requires one(1) non-driving day for 10 calendar days. This study examined the impacts of such policies on the different income classes using simulation analysis. We found that the impacts of market-oriented policies such as the imposition of road tolls and the increase of gasoline taxes is regressive. Also, we found that while the low and middle income private car users have incentive have incentive for public transportation use, the high income private car users have no incentive for public transportation use in many cases.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.4
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• pp.144-152
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• 2013

PRT(Personal Rapid Transit) system is a new transportation system which will meet increasing demands of traffic in Korea. It is also an environment-friendly transportation and automatically operated. For these reasons, researches on the PRT system are actively undergoing, but the PRT vehicles have different forms of subway, bus, etc. There are no design standards to evaluate structural integrity, yet. In this paper, Structural design specifications are derived, which are based on the performance test standard for EMU and the ASCE-APM standards. We also perform the static and fatigue analyses by FE simulation and suggest strategies to improve an initial structure design. In addition, we derived the design specifications for energy-absorbing structures to meet the conditions of the collision scenarios predefined from a view point of operation safety.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.804-811
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• 2015

The presence of responsive loads in the promising active distribution networks (ADNs) would definitely affect the power system problems such as distributed generations (DGs) studies. Hence, an optimal procedure is proposed herein which takes into account the simultaneous placement of DGs and smart meters (SMs) in ADNs. SMs are taken into consideration for the sake of successful implementing of demand response programs (DRPs) such as direct load control (DLC) with end-side consumers. Seeking to power loss minimization, the optimization procedure is tackled with genetic algorithm (GA) and tested thoroughly on 69-bus distribution test system. Different scenarios including variations in the number of DG units, adaptive power factor (APF) mode for DGs to support reactive power, and individual or simultaneous placing of DGs and SMs have been established and interrogated in depth. The obtained results certify the considerable effect of DRPs and APF mode in determining the optimal size and site of DGs to be connected in ADN resulting to the lowest value of power losses as well.