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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 18, Issue 6 - Dec 2000
Volume 18, Issue 5 - Oct 2000
Volume 18, Issue 4 - Aug 2000
Volume 18, Issue 3 - Jun 2000
Volume 18, Issue 2 - Apr 2000
Volume 18, Issue 1 - Feb 2000
Selecting the target year
Analysis of Seasonal Variation Effect of the Traffic Accidents on Freeway
Journal of Korean Society of Transportation, volume 18, issue 5, 2000, Pages 7~16
This paper is focused on verifying time-space repetition of the highway accident and finding the their causes and deterrents. We classify all months into several seasonal groups, develop the model for each seasonal group and analyze the results of these models for Joong-bu highway. The existence of seasonal effect is verified by the analysis or self-organizing map and the accident indices. Agglomerative hierarchical cluster analysis which is used to decide the seasonal groups in accordance with accident patterns, winter group, spring-fall group. and summer group. The accident features of winter group are that the accident rate is high but the severity rate is low. while those of summer group are that the accident rate is low but the severity rate is high. Also, the regression model which is developed to identify the accident Pattern or each seasonal group represents that the season-related factors, such as the amount of rainfall, the amount of snowfall, days of rainfall, days of snowfall etc. are strongly related to the accident pattern of evert seasonal group and among these factors the traffic volume, amount of rainfall. the amount of snowfall and days of freezing importantly affect the local accident Pattern. So, seasonal effect should be considered to the identification of high-risk road section. the development of descriptive and Predictive accident model, the resource allocation model of accident in order to make safety management plan efficient.
Comparison of Pedestrian Walking Characteristics Between Highway Crosswalk and Pedestrian Underpass
Journal of Korean Society of Transportation, volume 18, issue 5, 2000, Pages 17~29
This study was executed to research pedestrian characteristics at the Pedestrian underpass stairways and to compare the Pedestrian convenience for crossing the road via two different facilities, that is crosswalks and Pedestrian underpasses. The research scope of Pedestrian characteristics are the relationship of speed. density and flow. The comparison was done about average total walking distance, time and energy. It is observed that the upward speed is 0.67m/sec and the downward speed is 0.77m/sec at the stairs. In case of the simple crossing via the pedestrian underpass. average distance is 1.5 times longer, average time is 1.2 times more and average energy is 4.5 times move than those via the crosswalk. In case of the diagonal crossing, average distance is 1.5 times longer, average energy is 3.5 times mole than those via the crosswalk Average walking time is almost the same According to the field survey, most of Pedestrians prefer crosswalk to pedestrian underpass This Paper will be useful to determine wether to install crosswalk or not at the intersection where a pedestrian underpass is located already.
Traffic Flow Analysis for The Weaving Section Design on Urban Freeways (I)
Journal of Korean Society of Transportation, volume 18, issue 5, 2000, Pages 33~42
This Paper is a Part of research Project series to analyze unique traffic characteristics observable within weaving sections on urban freeways. The research objectives were to establish with headway distribution and maximum Passing volume on weaving sections the basis of weaving designs that can promote safety and efficiency. Until now, when one wants to check the maximum Passing volume on weaving sections, it is taken for granted using headway distribution of freeway basic section. However. it was suspected in this research that for weaving sections different form of headway distribution had better be used. To prove this, field surveys were made to count headway intervals which supposedly were influenced not only by freeway basic section flows but also by weaving flows and later on used to develop headway distribution for weaving sections. For validation of the developed headway distribution,
-test was applied to three different data set of observed headways, currently used headway distribution for basic sections(Pearson Type III distribution) and new headway distribution. The result indicated new headway distribution as the most appropriate distribution form. Also, maximum passing volume within weaving sections was calculated based on new headway distribution and compared with Drew's maximum Passing volume.
Development of Adjustment Factors for The Shared Left-turn Lane with U-Turn at the Signalized Intersection
Journal of Korean Society of Transportation, volume 18, issue 5, 2000, Pages 43~56
The Purpose of this study is to develop an adjustment factors for the shared left-turn lane with u-turns which are widely used. To develop the adjustment factors, saturation flow rates were collected at three sites for the double left-turn lanes (shared 1st lane with u-turns) and three sites for the single left-turn lane that shared with u-turns. And saturation flow rates of an exclusive u-turn lane were collected at the two selected sites, also, The variations of saturation flow rates according to the Percentages of u-turns were analysed. Simple linear regression models were developed for the relationship between the saturation flow rate and the u-turn percentage. The study results are as follows First, saturation flow rates of the exclusive u-turn lane on the road that divided by median was estimated about 1,512(Pcphgpl). Second, the average percentages of u-turns range of 10%∼30% and the maximum 60% Third, simple regression models had negative slopes. which supported a decrease in saturation flow rates as the Percentages of u-turns increased. Fourth. the adjustment factors for the shared left-turn lane with u-turns were developed according to the percentages of u-turns. By the developed adjustment factor, the Percentage of u-turns which are considered in th left turn analysis make the signalized intersection operation and capacity analysis more efficiently.
Development of Fuzzy Travel Time Estimator for Interrupted Traffic Flow
Journal of Korean Society of Transportation, volume 18, issue 5, 2000, Pages 57~67
Two fuzzy travel time estimators for interrupted traffic flow were developed based on field survey data and simulation data 7hat is collected from DETSIM, which is microscopic traffic simulation model that car-following theory is applied. One is FETTOS(Fuzzy Estimator of Travel Time using Occupancy and Spot speed) and the other is FETTOS(Fuzzy Estimator of Travel Speed using Volume and Occupancy). Fuzzy logic controller was applied to the estimators to deal with non-linear relationship between traffic variables and travel time. According to results of simulation and field survey. estimation of travel time can be modeled by using percent occupancy better than any other traffic variables. Detector location from storyline and signal timing Plan of intersection are affected to estimate travel time. With a few findings, the estimator was constructed and its performance was tested for observed travel time data and simulated data. FETTOS which needs signal timing plan and detector location estimates travel time with accurate better than FETSVO does. However. FETSVO has excellent transferability because the estimator needs set of input data only; volume and time mean speed.
Mode Choice Behavior Analysis of Commuter Feeder Passengers to Subway System
Journal of Korean Society of Transportation, volume 18, issue 5, 2000, Pages 69~82
When new subway lines are considered to construct in a large city, there is a need to establish the appropriate transfer systems between subway and other transit modes, so as to increase the use of subway system. In this study, a multi-nominal logit model is developed to analyze the travel characteristics and the mode choice of subway Passengers transferring to and from the buses, minibuses and taxi. These passengers represent a large Portion of transit Passengers in Pusan city It shows that the explanatory variables that affect Passengers\` mode choice are in order of OVIT(Out-of-Vehicle Travel Time), IVTT(In-Vehicle Travel Time), transit fare,. income, gender, and age in modeling. In particular, OVTT is shown to have more significant impact on the mode choice than IYTT due to the fact that transfer trip is involved only in a short distance. Variables associated with the travel costs, however, do have an insignificant impact on the mode choice. It shows that it would be a better Policy to improve the quality of transit service using additional financial resource by increasing transit fare rather than by reducing the fare to increase travel demand. It also shows that value of travel time of OVTT is remarkably higher than that of IVTT and value of travel time of taxi Passengers is much higher than that of minibus Passengers .
Comparison of Dynamic Origin Destination Demand Estimation Models in Highway Network
Journal of Korean Society of Transportation, volume 18, issue 5, 2000, Pages 83~97
The traffic management schemes through traffic signal control and information provision could be effective when the link-level data and trip-level data were used simultaneously in analysis Procedures. But, because the trip-level data. such as origin, destination and departure time, can not be obtained through the existing surveillance systems directly. It is needed to estimate it using the link-level data which can be obtained easily. Therefore the objective of this study is to develop the model to estimate O-D demand using only the link flows in highway network as a real time. The methodological approaches in this study are kalman filer, least-square method and normalized least-square method. The kalman filter is developed in the basis of the bayesian update. The normalized least-square method is developed in the basis of the least-square method and the natural constraint equation. These three models were experimented using two kinds of simulated data. The one has two abrupt changing Patterns in traffic flow rates The other is a 24 hours data that has three Peak times in a day Among these models, kalman filer has Produced more accurate and adaptive results than others. Therefore it is seemed that this model could be used in traffic demand management. control, travel time forecasting and dynamic assignment, and so forth.
A Development of a Path-Based Traffic Assignment Algorithm using Conjugate Gradient Method
Journal of Korean Society of Transportation, volume 18, issue 5, 2000, Pages 99~107
Path-based assignment(PBA) is valuable to dynamic traffic control and routing in integrated ITS framework. As one of widely studied PBA a1gorithms, Gradient Projection(GP) a1gorithm typically fields rapid convergence to a neighborhood of an optimal solution. But once it comes near a solution, it tends to slow down. To overcome this problem, we develop more efficient path-based assignment algorithm by combining Conjugate Gradient method with GP algorithm. It determines more accurate moving direction near a solution in order to gain a significant advantage in speed of convergence. Also this algorithm is applied to the Sioux-Falls network and verified its efficiency. Then we demonstrate that this type of method is very useful in improving speed of convergence in the case of user equilibrium problem.