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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Korean Society of Transportation
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Journal DOI :
Korean Society of Transportation
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Volume & Issues
Volume 22, Issue 7 - Dec 2004
Volume 22, Issue 4 - Aug 2004
Volume 22, Issue 3 - Jun 2004
Volume 22, Issue 2 - Apr 2004
Volume 22, Issue 1 - Feb 2004
Volume 22, Issue 6 - Jan 2004
Volume 22, Issue 5 - Jan 2004
Selecting the target year
Is Compact Urban Spatial Structure Effective for Public Transportation Mode?
Lee, Jae-Yeong ; Kim, Hyung-Chul ;
Journal of Korean Society of Transportation, volume 22, issue 3, 2004, Pages 7~16
The purpose of this study was to find the characteristics of travel behavior and accessibility in terms of spatial structure. We analyzed travel behaviors and accessibility using a mode choice model and the Complementary Accessibility Index(CAI). The urban spatial structures that were compared were a compact city (CC) versus a sprawled city (SC), and high residential density districts (HD) versus low residential density districts (LD). First, CC and HDs residents had a shorter commuting distance than the CC and LDs residents. Second, behavior models showed that the use of Private cars for commuting in SCs was found to be greater than private car use in CCs, and that public transportation modes would be encouraged in CCs. Third, changes associated with the time and cost of commuting by private car generally affect the demand for public transportation modes in the CC. Also, analysis of cross elasticity suggests that changes of subway travel time affect the demand for buses very elastically. Fourth, the CAI of SC and LD were superior to the CC and HD even though the SC inefficient urban forms in terms of spatial structure. So, the spatial distribution of population density was also found to be an important factor affecting accessibility and energy savings.
Study of the Efficiency of Airlines' and Cargo Divisions-Using a DEA Model Approach
Hong, Seock-Jin ;
Journal of Korean Society of Transportation, volume 22, issue 3, 2004, Pages 17~26
The role of air cargo within the air transport industry is gradually expanding. In fact, Boeing and Airbus have forecast that air cargo will increase by 6.4 % and 5.5 % respectively by 2020(2022 in the case of Boeing). This means that Boeing's air cargo will expand by 1.3 % more than Passenger demand over this period, while Airbus will see a 0.8 % increase. Moreover, Airbus is forecasting an average yearly growth of 7.0 % for air cargo within the Pacific region and from China to Europe. In addition to this high growth, air cargo has become one of the leading indicators of the international economy. Furthermore, the role of air cargo has gradually expanded within the air transport industry. Therefore, this study will analyze an airline efficiency that the activity is high on their cargo division. Airline selection done by the standard cargo revenue of 10 of the top airlines in 2002. The analysis is based on the Data Envelopment Analysis(DEA). This paper also strived to analyze the increase in management efficiency resulting from air cargo businesses, by comparing airline companies which had air cargo businesses with those who did not. The efficiency of the top 10 airlines with air cargo was compared with that of 9 American airlines(among the top 50 in the world). This analysis proved that the efficiency of these top ten air cargo airlines was higher than that of the other group. This indicates that airlines should form cargo divisions and expand them to achieve higher efficiency and compete against global integrators which now account for 50% of the global air cargo market.
Analysis of Transportation Safety Policies among 81 Cities in Korea
Kim, Chang-Kyun ; Kim, Dong-Gun ; Park, Yong-Hoon ;
Journal of Korean Society of Transportation, volume 22, issue 3, 2004, Pages 27~39
The previous studies on analyzing the effects of traffic safety policies are very limited. Implementing traffic safety policies in view of their own urban traffic characteristics would be fairly desirable to handle properly the traffic safety problems. The relationships between traffic accidents and traffic safety policies have been researched by classifying the eighty one cities in Korea into four groups in terms of the size of the city population. Statistical analysis have been conducted for traffic accidents data and traffic safety policies, respectively. In order to mearsure the effectiveness of the traffic policies in the real world, regression models have been developed by handling the accident data and policy data. As a result of analysing the data, the traffic policies have showed different effects according to the size of the cities. While budget investment policies had provided enormous influences to reduce traffic accidents in the big cities more than a half million polulation, traffic enforcement and traffic education have been so efficient to control traffic accident problems in the smaller cities less than a half million poluation.
Analysis of Participation Behavior and Factors of Urban Leisure Activity
Kim, Sang-Hwang ; Yun, Dae-Sic ; Kim, Kap-Soo ;
Journal of Korean Society of Transportation, volume 22, issue 3, 2004, Pages 41~48
This research develops a model of participation and scheduling choice of urban leisure activity. A nested legit model was found to be an appropriate approach. Data collected from Deagu and Pohang City were used for empirical estimation of model parameters. The empirical results confirmed several behavioral aspects associated with participation and scheduling choice of urban leisure activity. The paper presents a discussion on implications that can be inferred from the empirical results. Finally, future potential research question are also discussed.
Improvement of Trip Generation Model in Seoul Metropolitan Area
Kim, Jin-Ja ; Rhee, Jong-Ho ;
Journal of Korean Society of Transportation, volume 22, issue 3, 2004, Pages 49~58
The first and perhaps the most critical and perhaps the most important step in the process of predicting future traffic volume in a region (Zone) is to estimate the number of trips generated in from each traffic analysis zone. Most trip generation models for urban transportation planning, and highway in Korea are regression models. In Korea the category analysis has not been tried for last decades since the proper data such as the household travel behavior data have not been collected. Recently, the comprehensive household travel behavior survey such as
1996 The Household Travel Behavior Survey
2002 The Household Travel Behavior Survey
has been done. In this paper, the cross-classification tables of Seoul Metropolitan Area including the City of Seoul and Kyonggi Province are estimated by the category analysis. The tables are compared with regression models and
2002 The Household Travel Behavior Survey
data in terms of predictive capabilities in Seoul Metropolitan Area. Improvement strategies for trip generation forecast in Seoul Metropolitan Area are proposed.
Estimation of Benefits by Implementing Motor Vehicle Recall System
Sung, Nak-Moon ; Oh, Jae-Hak ; Oh, Ju-Taek ;
Journal of Korean Society of Transportation, volume 22, issue 3, 2004, Pages 59~67
On January 1, 2003, the motor vehicle management system in Korea was transformed from government's vehicle type approval to manufacturer's self-certification. The motor vehicle recall system with self-certification is an essential mechanism to place the liability of the vehicle defects on manufacturers and hence protect consumers from automobile accidents. This study provides a methodology to measure the benefits of motor vehicle recall system in two categories: benefits of reduction in traffic accidents and benefits of severity reduction in traffic accident. Applying the proposed methodology, the benefits of implementing motor vehicle recall system in Korea were estimated. It was estimated that 745 traffic accidents, 12 fatal accidents, and 1473 injury accidents were respectively reduced in 2002 due to implementation of motor vehicle recall system.
Causality of E-Commerce on the Door-to-door Delivery Service Market Using the Granger-Sims Causality Test
Lee, Woo-Seung ;
Journal of Korean Society of Transportation, volume 22, issue 3, 2004, Pages 69~84
After the mid of 1990's, as Internet application has quickly expanded into the whole world thanks to the advancement of information communication, the e-commerce has been growing quickly under the new market form called cyber market. The growth of e-commerce not only converts conventional distribution structure from off-line to on-line, but changes the logistics system itself. The e-commerce is not able to grew independently, however, can be grown by only connecting with logistics system in the actual transactions. For this reason, consequently the door-to-door delivery service (DDDS) is growing quickly with the rapid growth of the e-commerce. From this viewpoint, considering the environmental changes of the DDDS caused by the e-commerce within the urban area, it is interesting to examine what kind of growth factors for promoting the e-commerce effect the DDDS and play important role. The purpose of this study is to examine correlations between the e-commerce and the DDDS using serial data and to analyze the growth factors of the latter caused by the former. In this study, the growth factors are divided into 2 groups; inner factors and outer factors, and the outer factors are again divided into 2 groups; transportation factors and socio-economic factors. The e-commerce is regarded as one of the socio-economic factors. And this study analyzes the causality of the e-commerce on the DDDS market using the Granger-Sims causality test. The results of this study show that the Korea e-commerce has rapidly grown thanks to the growth of EDI(Electronic Data Interchange) enterprises, Internet shopping mall, internet users, and legal system establised for the e-commerce. At the same time, it also shows that this e-commerce has greatly influenced on the growth of the DDDS. Especially, it is analyzed that the government-leading information-oriented strategies have promoted the-commerce, subsequently the e-commerce has effected on the DDDS.
A Study of Relative Feeder-Cable Length and Vehicle Detection Length of Loop Detector
Oh, Young-Tae ; Kim, Nam-Sun ; Kim, Soo-Hee ; Song, Ki-Hyuk ;
Journal of Korean Society of Transportation, volume 22, issue 3, 2004, Pages 85~94
Loop detection systems have been used in real-time signal control system to collect traffic information for estimating queue lengths. The queue length algorithm uses speed as a key variable estimated from occupancy time and average vehicle length. The measurement of average vehicle length is affected from the lengths of feeder cable, but their effects have not yet been evaluated. In this study, the variability of average vehicle length due to the lengths of feeder cable is assessed through a field study, and a practical guidelines is proposed. By applying this result, the operational performance of real-time signal control system could be improved.
A Microscopic Analysis on the Shapes of Fundamental Diagram Using Time Gap
Kim, Tae-Wan ; Kim, Sang-Gu ; Kim, Young-Ho ; Son, Young-Tae ;
Journal of Korean Society of Transportation, volume 22, issue 3, 2004, Pages 95~105
The fundamental diagram is a important element in a variety of transportation studies. While various shapes of the fundamental diagram have been proposed and numerous debates on the best-fit fundamental diagram have been made, the reason why the fundamental diagram has many different shapes has not been well explained. This study introduces time sap as a key parameter to understand drivers' behavioral differences at different locations and traffic conditions, then relate to the shape of the fundamental diagram. From the freeway event detector data, it is shown that time gap follows a certain probabilistic distribution and its mean value varies along locations. It also turns out that drivers take different time gaps for different travel speeds. Three different types of time gap-speed diagrams are identified and matched to Greenberg, reversed-lambda, and inverted-V types of fundamental diagrams, respectively. This study explains the characteristics of fundamental diagrams using time gap as a microscopic variable and describes drivers' behavioral characteristics according to traffic and geometric conditions.
Development of Free Flow Speed Estimation Model by Artificial Neural Networks for Freeway Basic Sections
Kang, Jin-Gu ; Chang, Myung-Soon ; Kim, Jin-Tae ; Kim, Eung-Cheol ;
Journal of Korean Society of Transportation, volume 22, issue 3, 2004, Pages 109~125
In recent decades, microscopic simulation models have become powerful tools to analyze traffic flow on highways and to assist the investigation of level of service. The existing microscopic simulation models simulate an individual vehicle's speed based on a constant free-flow speed dominantly specified by users and driver's behavior models reflecting vehicle interactions, such as car following and lane changing. They set a single free-flow speed for a single vehicle on a given link and neglect to consider the effects of highway design elements to it in their internal simulation. Due to this, the existing models are limitted to provide with identical simulation results on both curved and tangent sections of highways. This paper presents a model developed to estimate the change of free-flow speeds based on highway design elements. Nine neural network models were trained based on the field data collected from seven different freeway curve sections and three different locations at each section to capture the percent changes of free-flow speeds: 100 m upstream of the point of curve (PC) and the middle of the curve. The model employing seven highway design elements as its input variables was selected as the best : radius of curve, length of curve, superelevation, the number of lanes, grade variations, and the approaching free-flow speed on 100 m upstream of PC. Tests showed that the free-flow speeds estimated by the proposed model were statistically identical to the ones from the field at 95% confidence level at each three different locations described above. The root mean square errors at the starting and the middle of curve section were 6.68 and 10.06, and the R-squares at these points were 0.77 and 0.65, respectively. It was concluded from the study that the proposed model would be one of the potential tools introducing the effects of highway design elements to free-flow speeds in simulation.
A Study to Predict the Traffic Accident Severity Level Applying Neural Network at the Signalized Intersections
Choi, Jae-Won ; Kim, Seong-Ho ; Cho, Jun-Han ; Kim, Won-Chul ;
Journal of Korean Society of Transportation, volume 22, issue 3, 2004, Pages 127~135
The number of signalized intersection accidents were about 21% of total traffic accidents in 2001 year, and there has been an increasing number of traffic accidents at intersection since 1990s. Although many studies for a safety evaluation methods at intersections have been progressed, most of these studies have not used general data which applied to all intersections. Therefore, this study developed two prediction models of the traffic accident severity levels using traffic conflict data that were collected at all of the intersections. These prediction models of the accident severity levels which are made up a multiple regression analysis and a neural network model that used the error backpropagation algorithm were made of using the gap between vehicles and speed, accident severity levels of existing traffic accident data at signalized intersection. When each of these two models predicted the twenty existing traffic accident severity levels, the prediction ability of neural network model was better than that of the multiple regression model, The collected data from the field which are gap between vehicles and speed of traffic conflict data at intersection were applied to the prediction models, and these models predicted that if the conflict connected a traffic accident, it will more or less raise the traffic accident severity level. When we evaluate the safety at intersection in case of lack of traffic accident data, we are able to collect such traffic conflict data from the field. Accordingly as these data is applied to the models, we can decide the risk-level at intersections which are based on the prediction of traffic accident severity levels.
Modelling En-route Diversion Behavior under On-site Traffic Information
Kim, Hye-Ran ; Chon, Kyung-Soo ; Park, Chang-Ho ;
Journal of Korean Society of Transportation, volume 22, issue 3, 2004, Pages 137~144
The real-time traffic information is considered to be the system to alleviate traffic congestion. An effective traffic information will help drivers make efficient travel decision, and network performance will be improved. To make efficient strategy of providing information, the analyst should quantify reduced congestion by the media traffic informations. Many other route diversion models considered only media-informations as information sources and ignored the impact of on-site informations such as visible delays and average speeds, which affect drivers' route diversion decision in practice. In those models, the effect of on-site informations could be treated to be the effect of media informations, and the effects of media informations would be over-estimated. The proposed model including the impact of on-site information can estimate the effect of media-informations. The results are expected to be applied to the analysis of traffic management policy such as ITS.
Development of Neural Network Based Cycle Length Design Model Minimizing Delay for Traffic Responsive Control
Lee, Jung-Youn ; Kim, Jin-Tae ; Chang, Myung-Soon ;
Journal of Korean Society of Transportation, volume 22, issue 3, 2004, Pages 145~157
The cycle length design model of the Korean traffic responsive signal control systems is devised to vary a cycle length as a response to changes in traffic demand in real time by utilizing parameters specified by a system operator and such field information as degrees of saturation of through phases. Since no explicit guideline is provided to a system operator, the system tends to include ambiguity in terms of the system optimization. In addition, the cycle lengths produced by the existing model have yet been verified if they are comparable to the ones minimizing delay. This paper presents the studies conducted (1) to find shortcomings embedded in the existing model by comparing the cycle lengths produced by the model against the ones minimizing delay and (2) to propose a new direction to design a cycle length minimizing delay and excluding such operator oriented parameters. It was found from the study that the cycle lengths from the existing model fail to minimize delay and promote intersection operational conditions to be unsatisfied when traffic volume is low, due to the feature of the changed target operational volume-to-capacity ratio embedded in the model. The 64 different neural network based cycle length design models were developed based on simulation data surrogating field data. The CORSIM optimal cycle lengths minimizing delay were found through the COST software developed for the study. COST searches for the CORSIM optimal cycle length minimizing delay with a heuristic searching method, a hybrid genetic algorithm. Among 64 models, the best one producing cycle lengths close enough to the optimal was selected through statistical tests. It was found from the verification test that the best model designs a cycle length as similar pattern to the ones minimizing delay. The cycle lengths from the proposed model are comparable to the ones from TRANSYT-7F.
Dynamic Capacity Concept and its Determination for Managing Congested Flow
Park, Eun-Mi ;
Journal of Korean Society of Transportation, volume 22, issue 3, 2004, Pages 159~166
The capacity concept presented in the Highway Capacity Manual is for steady-state traffic flow assuming that there is no restriction in downstream flowing, which is traditionally used for planning, design, and operational analyses. In the congested traffic condition, the control objective should be to keep the congested regime from growing and to recover the normal traffic condition as soon as possible. In this control case, it is important to predict the spatial-temporal pattern of congestion evolution or dissipation and to estimate the throughput reduction according to the spatial-temporal pattern. In this context, the new concept of dynamic capacity for managing congested traffic is developed in terms of spatial-temporal evolution of downstream traffic congestion and in view of the 'input' concept assuming that flow is restricted by downstream condition rather than the 'output' concept assuming that there is no restriction in downstream flowing (e.g. the mean queue discharge flow rate). This new capacity is defined as the Maximum Sustainable Throughput that is determined based on the spatial-temporal evolution pattern of downstream congestion. And the spatial-temporal evolution pattern is estimated using the Newell's simplified q-k model.
A Service Network Design Model for Rail Freight Transportation with Hub-and-spoke Strategy
Jeong, Seung-Ju ;
Journal of Korean Society of Transportation, volume 22, issue 3, 2004, Pages 167~177
The Hub-and-spoke strategy is widely used in the field of transportation. According to containerization and the development of transshipment technology, it is also introduced into European rail freight transportation. The objective of this article is to develop a service network design model for rail freight transportation based on the Hub-and-spoke strategy and efficient algorithms that can be applied to large-scale network. Although this model is for strategic decision, it includes not only general operational cost but also time-delay cost. The non-linearity of objective function due to time-delay factor is transformed into linearity by establishing train service variables by frequency. To solve large scale problem, this model used a heuristic method based on decomposition and three newly-developed algorithms. The new algorithms were examined with respect to four test problems base on the actual network of European rail freight and discussed the accuracy of solutions and the efficiency of proposed algorithms.
Analysis of Characteristics of the Dynamic Flow-Density Relation and its Application to Traffic Flow Models
Kim, Young-Ho ; Lee, Si-Bok ;
Journal of Korean Society of Transportation, volume 22, issue 3, 2004, Pages 179~201
Online traffic flow modeling is attracting more attention due to intelligent transport systems and technologies. The flow-density relation plays an important role in traffic flow modeling and provides a basic way to illustrate traffic flow behavior under different traffic flow and traffic density conditions. Until now the research effort has focused mainly on the shape of the relation. The time series of the relation has not been identified clearly, even though the time series of the relation reflects the upstream/downstream traffic conditions and should be considered in the traffic flow modeling. In this paper the flow-density relation is analyzed dynamically and interpreted as a states diagram. The dynamic flow-density relation is quantified by applying fuzzy logic. The quantified dynamic flow-density relation builds the basis for online application of a macroscopic traffic flow model. The new approach to online modeling of traffic flow applying the dynamic flow-density relation alleviates parameter calibration problems stemming from the static flow-density relation.
The Comparative Analysis of Evaluation Guidelines for ITS Projects
Lee, Yong-Taek ; Nam, Du-Hui ; Park, Dong-Ju ;
Journal of Korean Society of Transportation, volume 22, issue 3, 2004, Pages 215~226