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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 24, Issue 7 - Dec 2006
Volume 24, Issue 6 - Oct 2006
Volume 24, Issue 5 - Aug 2006
Volume 24, Issue 4 - Jun 2006
Volume 24, Issue 3 - May 2006
Volume 24, Issue 2 - Apr 2006
Volume 24, Issue 1 - Feb 2006
Selecting the target year
Link Travel Time Estimation Using Uncompleted Link-passing GPS Probe Data in Congested Traffic Condition
Sim, Sang-U ; Choe, Gi-Ju ;
Journal of Korean Society of Transportation, volume 24, issue 5, 2006, Pages 7~18
Data for travel information Provision are regularly aggregated to Provide travel time information in a reliable and convenient manner and to manage traffic data and information efficiently. In most of practices in Korea, the GPS based travel time data are mainly aggregated every 5 minutes As a result, some probes can't pass by a link within aggregation interval and thereby create uncompleted link passing data. But these data are mostly generated during the congested times and therefore a method that uses such uncompleted link passing data are required. This study estimated queue dissipation length, green time and cycle that use GPS spot speed and developed a link travel time estimation method using such uncompleted link passing data. It also presents method and the overall process of using such data to estimate link travel time in a more accurate manner. As a result, MAPE 1.98% and MAE 4.75 sec of link travel time accuracy improvement has been reported, which is not much different from the real link travel time. The method Proposed here would be an alternative to increase the amount of GPS probe data, especially in congested urban arterial case.
An Experimental Study on the Application of NTCIP to Korean Traffic Signal Control System
Go, Gwang-Yong ; Jeong, Jun-Ha ; Lee, Seung-Hwan ; An, Gye-Hyeong ;
Journal of Korean Society of Transportation, volume 24, issue 5, 2006, Pages 19~33
This paper presents the results of an experimental study on the application of NTCIP protocol to Korean traffic signal control system. For this study the communication Protocol of the existing traffic signal control system was adjusted to meet NTCIP standard. Management information base for Korea real-time traffic signal control system, message library of OER, traffic control center management software supporting SNMP/SFMP Protocol, and agent softwares for local controllers were developed during the experimental study. The applicability test of the adjusted system by NTCIP standard was performed. Fifty eight Percent of communication packets were lost at 2.400bps communication speed, which made the operation impossible. The experimentations with communication speeds 4,800bps and 9,600bps did not cause problems. In conclusion, to apply the NTCIP standard to domestic real-time traffic control system, communication environments need to be upgraded to 4,800bps or higher
A Study of Adjustment for Beginning & Ending Points of Climbing Lanes
Journal of Korean Society of Transportation, volume 24, issue 5, 2006, Pages 35~44
Acceleration and deceleration curves have been used for design purposes worldwide. The curve in design level has been regarded as an single deterministic curve to be used for design of climb lanes. It should be noted that the curve was originally made using ideal driving truck and that the curve is applied during design based on the assumption of no difference between ideal and real driving conditions. However. observations show that aged vehicles and lazy behavioring drivers nay make lower performance of vehicles than the ideal performance. The present paper provides the results of truck speeds at climbing lanes then probabilistic variation of acceleration and deceleration corves. For these purposes. a study about identification of vehicle makers, and weights for trucks at freeway toll gates and then observation of vehicle-following speed were performed. The 85%ile results obtained were compared with the deterministic performance curves of 180, 200, and 220 Ib/hp. It was identified that the performance of 85%ile results obtained from vehicle-following-speed observations were lower than one from deterministic performance curves. From these results, it may be concluded that at the beginning Point of climbing lanes additional
is necessary and that at the end point of climbing lanes
of extension is necessary.
Production Characteristics and Efficiency of Korean Railroad Industry using a Distance Function
Kim, Seong-Ho ;
Journal of Korean Society of Transportation, volume 24, issue 5, 2006, Pages 45~56
In order to construct an information pool on the production characteristics and efficiency of Korean railroad industry, various alternative approaches have to be applied. In this paper we present an empirical application of the distance function to measure the technical efficiency and the production characteristics of Korean railroad industry, The distance function firstly introduced by Shephard (1953) provides the advantage that it does not need information about prices, so it can accommodate the multiple output nature of the railway only using the quantifies as data. This is of great relevance in the context of the public sector such as railroad industry where there are often distinct control mechanisms on input prices. Also the distance function allows us to obtain a measure of technical efficiency as well as a measure of production characteristics. From annual data on Korean railroad industry during 1964-2004, multiple output distance function is estimated using quadratic programming model. The resulting technical efficiency estimates has tended to be improved over the period
. The indirect Morishima elasticities of substitution indicate that the substitutabilities for labor are relatively very low or impossible. The average scale elasticity is 2.7 which means that increasing the scale by 1per cent will result in an output increase by 2.7 percent. This result indicates that economies of scale are present in the Korean railroad industry.
A Study on the Estimation of Pedestrian Signal Timing
An, Gye-Hyeong ; Kim, Eun-Jeong ; Lee, Yong-Il ; Jeong, Jun-Ha ; Kim, Yeong-Chan ;
Journal of Korean Society of Transportation, volume 24, issue 5, 2006, Pages 57~66
This paper presents new pedestrian signal timings considering pedestrian demand Pedestrian characteristics, and land use which were obtained by Pedestrian characteristics field survey and pedestrian signal operation survey. Pedestrian signal timings suggested were compared to the existing pedestrian signal timings by using real field data. pedestrian characteristics field survey was conducted to collect pedestrian crossing speed data and reaction time data. Sixteen areas in Seoul were selected for the data collection. The average pedestrian crossing speed was 1.30m/sec and the 15th Percentile speed was 1.11m/sec. The average reaction time was 2.24 seconds. Pedestrian crossing speed differs by land use, road width. pedestrian age, sex, and number of Pedestrians. Reaction time also differs by road width, pedestrian age, and number of pedestrians. Statistical testing was performed to secure reliability of the collected data.
A Risk Quantification of Public Sector Comparator in the Financial Analysis of the BTL (Build-Transfer-Lease) Scheme of Railway Projects: a Case Study of the Haman-Jinju Link
Jang, Su-Eun ; Gang, Ji-Hye ;
Journal of Korean Society of Transportation, volume 24, issue 5, 2006, Pages 67~74
This paper proposes a way to a risk quantification of public sector comparator in the value-for-money test of the BTL (Build-Transfer-Lease) scheme in rail investment projects. Two principal risks that are project delay and budget increasing costs are identified and are empirically quantified with a case study of the Haman-Jinju link. The methodology suggested is expected to be a good reference for the similar research afterwards and also to help in settling down the scheme that is only an early stage.
Finding the Time Dependent K Least Time Paths in Intermodal Transportation Networks
Jo, Jong-Seok ; Sin, Seong-Il ; Im, Gang-Won ; Mun, Byeong-Seop ;
Journal of Korean Society of Transportation, volume 24, issue 5, 2006, Pages 77~88
The purpose of this study is to Propose the time dependent K-least time path algorithm applicable to a real-time based operation strategy in multi-modal transportation network. For this purpose, we developed the extended method based on entire path deletion method which was used in the static K-least time path algorithm. This method was applied to time dependent K-least time path algorithm to find k least time paths in order based on both time dependant mode-link travel time and transfer cost In particular, this algorithm find the optimal solution, easily describing transfer behavior, such as walking and waiting for transfer by applying a link-based time dependent label. Finally, we examined the verification and application of the Proposed algorithm through case study.
Analysis of the Elderly Travel Characteristics and Travel Behavior with Daily Activity Schedules (the Case of Seoul, Korea)
Seo, Sang-Eon ; Jeong, Jin-Hyeok ; Kim, Sun-Gwan ;
Journal of Korean Society of Transportation, volume 24, issue 5, 2006, Pages 89~108
Korea has been entering the ageing society as the population of age over 65 shared over 7% since the year 2000. The ageing society needs to have transportation facility considering elderly people's travel behavior. This study aims to understand the elderly people's travel behavior using recent data in Korea. The activity schedule approach begins with travel outcomes are part of an activitv scheduling decision. For tho?e approach. used discrete choice models (especially. Nested Logit Model) to address the basic modeling problem capturing decision interaction among the many choice dimensions of the immense activity schedule choice set The day activity schedule is viewed as a sot of tours and at-home activity episodes tied togather with overarching day activity pattern using the Seoul Metropolitan Area Transportation Survey data, which was conducted in June, 2002. Decisions about a specific tour in the schedule are conditioned by the choice of day activity pattern. The day activity scheduling model estimated in this study consists of tours interrelated in a day activity pattern. The day activity pattern model represents the basic decision of activity participation and priorities and places each activity in a configuration of tours and at-home episodes. Each pattern alternative is defined by the primary activity of the day, whether the primary activity occurs at home or away, and the type of tour for the primary activity. In travel mode choice of the elderly and non-workers, especially, travel cost was found to be important in understanding interpersonal variations in mode choice behavior though, travel time was found to be less important factor in choosing travel mode. In addition, although, generally, the elderly was likely to choose transit mode, private mode was preferred for the elderly over 75 years old owing to weakened physical health for such things as going up and down of stairs. Therefore. as entering the ageing society, transit mode should be invested heavily in transportation facility Planning tor improving elderly transportation service. Although the model has not yet been validated in before-and-after prediction studies. this study gives strong evidence of its behavioral soundness, current practicality. and potential for improving reliability of transportation Projects superior to those of the best existing systems in Korea.
Development of Predicting Models of the Operating Speed Considering on Traffic Operation Characteristics and Road Alignment Factors In Express Highways
Lee, Jeom-Ho ; Hong, Da-Hui ; Lee, Su-Beom ;
Journal of Korean Society of Transportation, volume 24, issue 5, 2006, Pages 109~121
The road should be designed in the consistent alignment which the driver can drive safely. Also, proper highway environments in order to maintain optimal operational speeds on highway sections should be provided In design stage, for highway environments, it is essential for an operational speed estimation model to different highway environments. If a method which could evaluate the status of the road safety is developed through this operational speed estimation model, it is possible to provide safe and more comfortable highways to road users. In the study factors to effect on operational speeds are classified into three groups horizontal & vertical alignments and traffic operation characteristic factors. Factors are chosen to effect on operational speeds by using collation analysis as classifications of tangent sections, horizontal curve sections and vertical curve sections. In order to develop operational speed estimation models in express highways, multi-regression analysis has been used in this study using the selected factors. This study has meaning that the developed estimation models for operational speeds and evaluation of degree of safety to horizontal and vortical alignments simultaneous. In order to represent whole area of the country with the developed models, the models should be re-analyzed with vast data related with road alignment factors in the near future.
Development of Determining Technique of Optimum Signal Time of Intersections On Median Exclusive Bus Lane using Bus-only Signal
Kim, Bo-Gyeom ; Kim, Seung-Il ; Kim, Yeong-Chan ; Kim, Jin-Tae ;
Journal of Korean Society of Transportation, volume 24, issue 5, 2006, Pages 123~133
Seoul and many large cities in Korea have implemented Median Exclusive Bus Lane(MEB). But exclusive bus lane in the middle of the road caused new contradictions between left turn movement and through bus movement and several signal operation techniques like 'left turn Protected' and 'overlap phase' couldn't be applied in intersections on MEB. We suggest 'Bus-only Signal for median lane technique as solution of these problems This study presents optimum signal time design process and detailed algorithms for intersections where bus-only signals are installed. As a test field. we took Yang-Je intersection where Median Exclusive Bus Lane go through. and have large gap in volume of left turn in main direction. And we verified that revised optimum signal time including overlap phase can reduce average delay time of vehicle through before and after simulation
Flow-density Relations Satisfying Stationary Conditions using Statistical Analysis
Kim, Yeong-Ho ;
Journal of Korean Society of Transportation, volume 24, issue 5, 2006, Pages 135~142
The flow-density relations represent equilibrium relations between flow and density in the stationary state. Using individual vehicle data this paper proposed a method to 131ter traffic data in the stationary state and showed flow-density relations produced by the traffic data in the stationary state. The Proposed method is based on the idea that free flow and congested flow show totally different traffic behaviors and time series of the traffic data observed at detection stations. The traffic data collected from the stationary state in the free flow using this filtering method consist in the left branch of the flow-density relation and the traffic data collected from the stationary state in the congested flow consist in the right branch of the flow-density relation. The traffic data in the stationary state skew reproducible flow-density relation in the almost whole range of the traffic flow.