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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 29, Issue 6 - Dec 2011
Volume 29, Issue 5 - Oct 2011
Volume 29, Issue 4 - Aug 2011
Volume 29, Issue 3 - Jun 2011
Volume 29, Issue 2 - Apr 2011
Volume 29, Issue 1 - Feb 2011
Selecting the target year
A Study on Operation Technique and Effective Analysis of Expressway Variable Speed Limits Control
Im, Gwan-Su ; Nam, Du-Hui ;
Journal of Korean Society of Transportation, volume 29, issue 2, 2011, Pages 7~14
This paper discusses operational technique and effectiveness of Variable Speed Limits system that is implemented to control the traffic-flow on the Naebu Expressway. As the first step of the analysis, traffic data collected from vehicle detectors are corrected and smoothed. Applying a pattern analysis technique to the traffic data, the weekday traffic is classified into four different groups, and median of each group is calculated. Using three state variables, i.e., diverted traffic volume, average density and average speed, the conditions of roadway segments are determined. Computational outputs resulted from the application of the proposed model to the scenarios show that implementation of Variable Speed Limits system improved both safety and efficiency of the expressway. For the operational strategy, this paper also presents the change rate of the speed limit, and the effective duration of the speed limit according to the entering traffic volume.
Equity Analysis of Feeder Bus Routes in Seoul using DEA(Data Envelopment Analysis) Model
Han, Jin-Seok ; Kim, Hye-Ran ; Go, Seung-Yeong ;
Journal of Korean Society of Transportation, volume 29, issue 2, 2011, Pages 15~24
This study discusses an equity analysis performed to supplement the existing bus service evaluation system. The equity of 179 feeder bus routes in the city of Seoul(Year 2009) is analyzed by employing the modified BCC model along with the desirable inputs such as a number of bus stops and a frequency of operations. In the analysis, each DMU (Decision Making Unit) is assumed to use the desirable inputs, and produces both the index of equity and the index of accessibility. We apply an input-oriented modified BCC model to analyze the equity of the DMUs. The computational result indicates that only 9% of the feeder bus routes are equitable among the total DMUs and the average equity estimate is 0.702. It is also suggested that on average approximately 60% increases of desirable inputs (i.e., a number of bus stops and a frequency of operations) are needed in order to improve equity of DMU in the city of Seoul. The result of the tobit regression analysis on the determinant factors affecting the equity of DMUs shows that all the independent variables (i.e., a number of bus stops and a frequency of operations) are statistically significant at 5% significance level, and the number of bus stops is found to be the most influential factor.
A Study on the Calculation of
Emission and Road Freight Environmental Index for Logistics Companies
Kim, Jong-Hyeon ; Kim, Hong-Sang ; Choe, Sang-Jin ; Park, Seong-Gyu ; Kim, Jeong ; Jang, Yeong-Gi ;
Journal of Korean Society of Transportation, volume 29, issue 2, 2011, Pages 25~35
In order to reduce Green House Gas(GHG) reduction in the road freight sector and thus establish green logistics, running efficiency of goods vehicles is of paramount importance. Providing effective transportation infrastructure can contribute to achieve the green logistics by reducing empty running of heavy goods vehicles and van, increasing the average payload on the vehicle, and shifting the transportation mode. In order to reduce the environmental impact from the road freight sector, it is essential to quantify the amount of environmental loading from the sector. However, any systematic survey on the environmental loading from the logistics companies has not been carried out in Korea. In this study, the environmental index for the road freight sector is defined as the amount of
emission per ton km generated from goods vehicles. The computational analysis shows that the average
emission per ton km generated by the logistics companies in Korea is
. Compared to UK (=
) and France (=
), the efficiency of logistics in Korea is 2.8 and 3.7 times as low as in the advanced countries. It also indicates that the main reasons for the low efficiency are mainly due to the high rate of empty operation of goods vehicles and the low payload.
The Relationship between Subjective Driving Workload and Effects of PG Technology
O, Ju-Seok ; Hwang, Bong-Gi ; Lee, Sun-Cheol ; Lee, Jong-Hak ; Kim, Jong-Min ; No, Gwan-Seop ;
Journal of Korean Society of Transportation, volume 29, issue 2, 2011, Pages 37~45
The main objective of this study is two-fold: 1) to analyze the effect of PG technology application on road user's satisfaction and driving speed, and 2) to investigate the relationship between driver's subjective workload level and their reactions related to the PG technology application. Based on the result of field observation, the experimental scenario for driving simulation study was prepared. The experimental results showed that drivers were more satisfied to the road condition with PG technology applied, and even the pattern of speed reduction was more stable than control condition. The pattern of speed reduction along driver's subjective driving workload level were slightly different by physical road condition, and road user's satisfaction was revealed to be negatively correlated with their subjective driving workload level. This result indicates that depending on situation and driver characteristic, information for the drivers could be nothing more than nuisance that just distracts drivers. In order to facilitate the implementation of PG technology in Korea, further study on related human factors, especially for those who are weak in traffic situations, is recommended.
A Study on Developing the Performance Audit Methodology for Performance Evaluation of Transportation Planning Process
Lee, Yong-Taek ; O, Chang-Seok ;
Journal of Korean Society of Transportation, volume 29, issue 2, 2011, Pages 47~58
Nowaday OECD countries actively introduce the performance audit to evaluate the performance of public policies. Motivated by the current trend in practice, this paper presents performance audit indices and methodology developed for evaluating the transportation investment projects and policies. The main contribution of this study would be twofold:1) key performance indices, 5Es + 4Cs rule, and methodology of performance audit are derived from foreign (GAO, NAO) and domestic (BAI) audit reports; 2) checklists (key issues and focuses) of performance audit are suggested as ranks. It is also suggested that further studies are needed to maintain the indices and the methodology to achieve sustainable performance of transportation projects and policies.
Impact Conditions of Performance Evaluation, and Development of High-Performance Roadside Barrier for Longitudinal Barriers in Smart Highway
Kim, Dong-Seong ; Kim, Kee-Dong ; Ko, Man-Gi ; Jang, Dae-Young ;
Journal of Korean Society of Transportation, volume 29, issue 2, 2011, Pages 59~67
To minimize the degree of damage in the SMART highway's punctuality and safety occurred from the car-barrier collisions, the impact conditions for longitudinal barriers in SMART highway was determined to be significantly larger than the existing maximum impact conditions. Results from computer simulation runs show that the existing domestic highest-performance roadside barrier did not satisfy the suggested impact conditions. The newly developed N-class barrier designed with computer simulation model and verified by full-scale crash tests has satisfied the SMART highway impact conditions in terms of occupant safety indexes and structural adequacy.
Analysis of Spatial Influential Zone for Road Sign using the Variable Radius Buffer Model
Cheon, Seung-Hun ; Gwon, Seong-Geun ; Nam, Dae-Sik ; Im, Hyeon-Seop ; Lee, Yeong-In ;
Journal of Korean Society of Transportation, volume 29, issue 2, 2011, Pages 71~80
Almost all Drivers who are not familiar with local areas usually rely on road signs equipped along the roadways. The road signs in Korea present the name of the city along the driver’s direction. The consistency of guided name on the road-signs is important for drivers. The discordances among road signs frustrate drivers particularly when the drivers are confused with whether or not they are in the right direction. There are several studies focusing on the continuity of information on the road signs. Most of the researches, however, do not suggest the objective way but diagnose present problem. Applying the Analytic Hierarchy Process (AHP), we evaluate the impact of information on road signs and select the candidate information considering the score and limited number of information. We also suggest the reasonable spatial influence area of road sign information using geo-spatial analysis. From this study, we expect that the director in charge of selecting information can make decision reasonably without difficulties of choosing information.
Integrated Trip Distribution/Mode Choice Model and Sensitivity Analysis
Im, Yong-Taek ;
Journal of Korean Society of Transportation, volume 29, issue 2, 2011, Pages 81~89
Trip distribution is the second step of the conventional travel demand estimation process, which connects trips between origin and destination, while transport mode choice is the third step of the process, which chooses transport mode among several modes serving for each origin-destination pair. Although these two steps have closely connected, they have been estimated independently each other in the estimation procedure. This paper presents an integrated model combining trip distribution and transport mode choice, and also presents its solution algorithm. The model integrates gravity model adopted for the trip distribution process with logit model employed for the mode choice process. The model would be expected to cope with the inconsistency issue existing in the conventional travel demand estimation procedure. This paper also presents an equilibrium condition, sensitivity of the model, and compares them with those of existing models.
A Strict Hub Network Design with Single Allocation for Road Freight Transportation
Kim, Nam-Ju ; Kim, Yong-Jin ;
Journal of Korean Society of Transportation, volume 29, issue 2, 2011, Pages 91~100
Hub network design for freight transportation is a decision process that determines hub locations together with freight transportation routes among shippers so as to ultimately minimize total logistics cost. This study presents the optimal location of hubs by strict hub network design policy with single allocation, which overcomes the limitation of Kim et al. (2008) that does not allow direct transportation among shippers. The greedy-interchange algorithm is employed for hub location decision process, and EMME/2 is adopted for the route searching process. Application of the processes to the nationwide highway network shows that the best hub locations in order are Seoul metropolitan, GyeongNam, Chung-nam, Jeon-Nam, Gyeong-Buk, Chung-Buk, and the locations are concentrated on the Seoul-Busan corridor. The strict hubnetwork design policy with single allocation increases the transportation distance but decreases the transportation cost by passing through the hubs instead of direct transportation. The reduction in total transportation cost can be achieved as the number of hubs increases, but the amount of the reduction gradually decreases because the cost reduction from the decrease in detour transportation distance between non-hubs and hubs becomes less than the discount reduction from dispersion of inter-hubs transportation volumes.
Trip Generation Model based on Geographically Weighted Regression
Kim, Jin-Hui ; Park, Il-Seop ; Jeong, Jin-Hyeok ;
Journal of Korean Society of Transportation, volume 29, issue 2, 2011, Pages 101~109
In most of the urbanized cities, socio-economic attributes tend to cluster as patterns of similarity in space, namely spatial autocorrelation, by agglomeration forces. The classical linear regression model, the most frequently adopted in the trip generation step, cannot sufficiently represent this effect. In order to take into account the effect properly, we need a model which adequately deals with the spatial dependence patterns. In this study, the Geographically Weighted Regression (GWR) model is adopted as an alternative method for the local analysis of relationships in multivariate data sets; that is GWR extends this traditional regression framework by estimating local rather than global parameters. This study shows the existence of spatial effects in the production and attraction of home base/non-home based trips through the GWR model using travel data collected in Daegu metropolitan area. Furthermore, LISA is employed to verify the fact that the local spatial autocorrelation exists.
Development and Evaluation of a Left-Turn Actuated Traffic Signal Control Strategy using Image Detectors
Eun, Ji-Hye ; O, Yeong-Tae ; Yun, Il-Su ; Lee, Cheol-Gi ; Kim, Nam-Seon ; Han, Ung-Gu ;
Journal of Korean Society of Transportation, volume 29, issue 2, 2011, Pages 111~121
This paper discusses a method for optimizing the semi-actuated traffic signal control system by adjusting the initial interval according to the number of vehicles waiting for the green light in the actuated phase. We also present a Left-Turn actuated traffic signal control strategy that examines the vehicular noise in the detection area and determines the phase extension and the gap-out. In order to detect the vehicles in real-time, an image detector's Video Image Tracking technology was adopted. A 'Zone in Zone'method was implemented, and the image detection area is segmented into three zones: 1) Zone1 for verifying a vehicles obligatory presence, 2) Zone2 for counting the standby vehicles, and 3) Zone3 for examining the number of vehicles that have passed. The on-site assessment of the Left Turn Actuated Control is carried out using CORSIM, and the results show that the Control Delay decreased by 23.10%, 15.06%, and 4.34% compared to the delays resulted from pre-timed control, semi-actuated control-1 and semi-actuated control-2 traffic signal control systems respectively. The Queue Time also decreased by 36.24%, 20.10% and the Total Time by 14.36%, 7.02% for the same scenario. Which clearly demonstrates the operational efficiency. A sensitivity analysis reveals that the improvement from the propose traffic control strategy tends to increase as the through traffic volume reaches a saturated condition and the left-turn traffic volume decreases.
A Road Surface Temperature Prediction Modeling for Road Weather Information System
Yang, Chung-Heon ; Park, Mun-Su ; Yun, Deok-Geun ;
Journal of Korean Society of Transportation, volume 29, issue 2, 2011, Pages 123~131
This study proposes a model for road surface temperature prediction on basis of the heat-energy balance equation between atmosphere and road surface. The overall model is consisted of two types of modules: 1) Canopy 1 is used to describe heat transfer between soil surface and atmosphere; and 2) Canopy 2 can reflect the characteristics of pavement type. Input data used in the model run is obtained from the Korea Meteorological For model validation, the observed and predicted surface temperature data are compared using data collected on MoonEui Bridge along CheongWon-Sangju Expressway, and the comparison is made on winter and other seasons separately. Analysis results show that average difference between two temperatures lies within
which is considered as appropriate from a micrometeorology point of view. The model proposed in this paper can be adopted as a useful tool in practical applications for winter maintenance. This study being a fundamental research is anticipated to be a starting point for further development of robust surface road temperature prediction algorithms.