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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 33, Issue 6 - Dec 2015
Volume 33, Issue 5 - Oct 2015
Volume 33, Issue 4 - Aug 2015
Volume 33, Issue 3 - Jun 2015
Volume 33, Issue 2 - Apr 2015
Volume 33, Issue 1 - Feb 2015
Selecting the target year
International Comparison of Railway Freight Performance
KIM, Young Joo ; KWON, Yong Jang ; HUR, Jun ; CHUNG, Sung Bong ;
Journal of Korean Society of Transportation, volume 33, issue 5, 2015, Pages 431~440
DOI : 10.7470/jkst.2015.33.5.431
This study aims to quantify the railway freight performance using various indicators, to compare it over many countries, and to evaluate efficiency of railway freight in Korea. The indicators developed in this study was classified into two categories; country-specific and company-specific indicator. The former includes freight train density, average gross train load and average haul while the latter contains revenue/ton-km, ratio of operating costs to revenue, revenue per employee, ton-km per employee, costs per ton-km and ratio of labor costs to total operating costs. The results of this study shows that Korail performance is in low efficiency due to multi-frequency small amounts transport. The productivity of railway freight in Korea represented as ton-km per employee appears to be lower than that of other oversea companies considered in this study.
Right-Turn Vehicle Supplementary Signal Improvement at Intersections
LEE, Nam Soo ; KIM, Yu Chan ; LIM, Joon Beom ; KIM, Youngchan ;
Journal of Korean Society of Transportation, volume 33, issue 5, 2015, Pages 441~448
DOI : 10.7470/jkst.2015.33.5.441
This study aims to suggest a reasonable signal operation method for right-turn traffic management. It was found that the right-turn vehicle supplementary signal is currently operated without clear regulations or criteria. It was also analyzed that right-turn supplementary signals are used without consistency, there is a risk of traffic accidents due to the discordance between supplementary signals and traffic signals of forward vehicles, there is a lack of basis for prohibition of a right turn when right-turn vehicle's supplementary signal is red and the flashing red signal is used in a different sense from the law. In order to see the effect of the installed right-turn vehicle supplementary signals on traffic signal violation, a field investigation was conducted. As the result, there was a high proportion of signal violation on the approach lane with right-turn supplementary signals and this means that right-turn supplementary signals hardly influenced the reduction in proportion of signal violation during a right turn. Additionally, a survey was carried out to see if there were differences in driver's interpretation of traffic signals depending on the installation of right-turn supplementary signals. As the result of the survey, there were no differences in interpretation of traffic signals depending on the installation of right-turn supplementary signals or the types of right-turn supplementary signals. A right turn when the signal was red did not lead to serious traffic accidents, so it is thought that there should be a careful consideration of a total ban on a right turn when the signal is red, in order to prevent driver's confusion due to the change of the signal system. Unless there is a disturbance to cars and pedestrians after a temporary stop when the signal is red, there is a need to specify that vehicles must stop temporarily in the Road Traffic Act to facilitate a right turn. What this study finally suggested is to use tri-colored arrow signals for right-turn car supplementary signals to convey a signal to a driver clearly.
Analysis on the Correction Factor of Emission Factors and Verification for Fuel Consumption Differences by Road Types and Time Using Real Driving Data
LEE, Kyu Jin ; CHOI, Keechoo ;
Journal of Korean Society of Transportation, volume 33, issue 5, 2015, Pages 449~460
DOI : 10.7470/jkst.2015.33.5.449
The reliability of air quality evaluation results for green transportation could be improved by applying correct emission factors. Unlike previous studies, which estimated emission factors that focused on vehicles in laboratory experiments, this study investigates emission factors according to road types and time using real driving data. The real driving data was collected using a Portable Activity Monitoring System (PAMS) according to road types and time, which it compared and analyzed fuel consumption from collected data. The result of the study shows that fuel consumption on national highway is 17.33% higher than the fuel consumption on expressway. In addition, the average fuel consumption of peak time is 4.7% higher than that of non-peak time for 22.5km/h. The difference in fuel consumption for road types and time is verified using ANOCOVA and MANOVA. As a result, the hypothesis of this study - that fuel consumption differs according to road types and time, even if the travel speed is the same - has proved valid. It also suggests correction factor of emission factors by using the difference in fuel consumption. It is highly expected that this study can improve the reliability of emissions from mobile pollution sources.
Development of Mode Choice Model for the Implementation of Next-generation High Speed Train(HEMU-430X)
LEE, Kwang Sub ; CHUNG, Sung Bong ; EOM, Jin Ki ; NAMKUNG, Baek Kyu ; KIM, Seok Won ;
Journal of Korean Society of Transportation, volume 33, issue 5, 2015, Pages 461~469
DOI : 10.7470/jkst.2015.33.5.461
The next generation high-speed train, HEMU-430X, was developed and is now being tested. However, the existing mode choice models based on the guidelines for feasibility studies do not consider a high-speed train with a higher speed than KTX. This limitation might result in inaccurate demand forecasting. In this research, a stated preference survey was conducted in order to supplement the problem by considering the characteristics of HEMU-430X. Based on the survey results, this research developed two mode choice models, including a multinomial logit model and a nested logit model. For this purpose, the utility functions of travel time and travel costs were estimated using a Limdep 8.0 NLOGIT 3.0 package. After comparing the two models, it was concluded that the nested logit model is appropriate. The paper suggested a plan to implement the nested logit model and presented a policy implication.
Preference Analysis of Traffic Information Service Depending on Smart Phone Possession
HEO, Min ; KIM, Hoe Kyoung ;
Journal of Korean Society of Transportation, volume 33, issue 5, 2015, Pages 470~477
DOI : 10.7470/jkst.2015.33.5.470
VMS informs the public of traffic and weather information in real time and functions to facilitate traffic flow. However, as smart phone navigation becomes more popular with the rapid propagation of the smart phone, the efficiency and applicability of VMS are challenged. Accordingly, this study aims to investigate the drivers' preference for the traffic information service between VMS and smart phone navigation by conducting a survey using a stated preference in Busan Metropolitan City in August 2013. This study found that 60% of survey respondents prefer VMS to the smart phone navigation. Further analysis to investigate the preference focused on the smart phone users revealed that female, younger, more educated, and less experienced drivers more rely on the smart phone navigation. Consequently, this study implicates that private and governmental institutes have to take a measure to develop the integrated traffic information system.
A Variable Speed Limits Operation Model to Minimize Confliction at a Bottleneck Section by Cumulative Demand-Capacity Analysis
LEE, Junhyung ; SON, Bongsoo ;
Journal of Korean Society of Transportation, volume 33, issue 5, 2015, Pages 478~487
DOI : 10.7470/jkst.2015.33.5.478
This study proposed a Variable Speed Limits(VSL) algorithm to use traffic information based on Cumulative Demand-Capacity Analysis and evaluated its performance. According to the analysis result, the total of delay consisted of 3 separate parts. There was no change in total travel time although the total of delay decreased. These effects was analysed theoretically and then, evaluated through VISSIM, a microscopic simulator. VISSIM simulation results show almost same as those of theoretical analysis. Furthermore in SSAM analysis with VISSIM simulation log, the number of high risk collisions decreased 36.0 %. However, the total delay decrease effect is not real meaning of decrease effect because the drivers' desired speed is same whether the VSL model is operated or not. Nevertheless this VSL model maintains free flow speed for longer and increases the cycle of traffic speed fluctuation. In other words, this is decrease of delay occurrence and scale. The decrease of speed gap between upstream and downstream stabilizes the traffic flow and leads decrease number of high risk collision. In conclusion, we can expect increase of safety through total delay minimization according to this VSL model.
Models for Determining the Vehicle and Pedestrian Volumes for the installation of Pedestrian Pushbuttons
YOON, Seung Sup ; YANG, Jae Ho ; KIM, Nam Seok ;
Journal of Korean Society of Transportation, volume 33, issue 5, 2015, Pages 488~496
DOI : 10.7470/jkst.2015.33.5.488
The main reason to install pedestrian pushbuttons is improving traffic operations. The current guideline for the installation of signal systems with pedestrian pushbuttons is car-oriented. It is difficult to clearly understand the guideline because there isn't an in-depth study to compare the pros and cons of the pedestrian- and vehicle-oriented methods in terms of waiting time. Thus, this study aims to estimate the waiting times of pedestrians and vehicles. The two delay times are compared considering the hypothetical circumstances such as geometry, pedestrian crossing time, pedestrian/vehicle counts and arrival distribution. The results show that when the pedestrian traffic volume exceeds 97 ped/h in the case of a two-lane road (one lane in each direction) the pushbutton system is effective and beneficial to pedestrians. It means that the total waiting time of pedestrians is less than the one of vehicles. Additional four scenarios are designed and tested by varying the number of lanes and design speeds. In conclusion, the pushbutton signal is more beneficial for pedestrians when the number of pedestrians is less than or equal to 85, 70, and 70 ped/h for the three-lane scenario, the four-lane with the design speed of 80km/h scenario, and the four-lane with the design speed of 100km/h, respectively.
Development of Freeway Traffic Incident Clearance Time Prediction Model by Accident Level
LEE, Soong-bong ; HAN, Dong Hee ; LEE, Young-Ihn ;
Journal of Korean Society of Transportation, volume 33, issue 5, 2015, Pages 497~507
DOI : 10.7470/jkst.2015.33.5.497
Nonrecurrent congestion of freeway was primarily caused by incident. The main cause of incident was known as a traffic accident. Therefore, accurate prediction of traffic incident clearance time is very important in accident management. Traffic accident data on freeway during year 2008 to year 2014 period were analyzed for this study. KNN(K-Nearest Neighbor) algorithm was hired for developing incident clearance time prediction model with the historical traffic accident data. Analysis result of accident data explains the level of accident significantly affect on the incident clearance time. For this reason, incident clearance time was categorized by accident level. Data were sorted by classification of traffic volume, number of lanes and time periods to consider traffic conditions and roadway geometry. Factors affecting incident clearance time were analyzed from the extracted data for identifying similar types of accident. Lastly, weight of detail factors was calculated in order to measure distance metric. Weight was calculated with applying standard method of normal distribution, then incident clearance time was predicted. Prediction result of model showed a lower prediction error(MAPE) than models of previous studies. The improve model developed in this study is expected to contribute to the efficient highway operation management when incident occurs.