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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 11, Issue 3 - Jun 1993
Volume 11, Issue 2 - Apr 1993
Volume 11, Issue 1 - Jan 1993
Selecting the target year
The Geography of Joruney-to-work in the Seoul Metropolitan Area
Journal of Korean Society of Transportation, volume 11, issue 1, 1993, Pages 5~22
This study examines the 1980 Census and the 1987 Travel Survey data sets, in order to identify commuting trends in the Seoul Metropolitan Area. The commuting field of Seoul includes the cities and counties contiguous to Seoul, as well as Inchon, Suwon and Ansan City and Paju County. The study finds little support for the expansion of the commuting field toward distant counties of Kyonggi Province; instead an intensification of commuting within the field is more salient. The most prominent trend, within the city limit of Seoul, is that journey-to-work toward the city center has decreased whereas peripheral journeys increased considerably. The work trips have increased most in the southwestern sector of the city; a moderate increase in the northeastern and southwestern sectors; and decreases in the center and the northwestern sector of the city. Factorial analyses of the work trip data also reveal the emergence of sub-regions of journey-to-work in the peripheries of the city. Such a spatial pattern of commuting changes resemble that of population changes, and correspond in part to the layout of the subway system.
Development of Two-lane, Two-way Highway Simulation Program(TWOPAS) for Korean Condition
Journal of Korean Society of Transportation, volume 11, issue 1, 1993, Pages 23~36
The two-lane, two-way highway simulation program(TWOPAS) is evaluated for Korean Highway Capacity Manual Study. TWOPAS program input variables, especially related vehicle performance, traffic flow relationship, car-following model and passing logic are examined and modified through the analysis results of our two-lane, two-way highway traffic characteristics. Simulation outputs with and without modification are compared with the field data. The results show that improved TWOPAS program(TWOPAS KI) is well suitable for simulating our two-lane, two-way highway condition.
Mode Choice Models for Freight Transport : a Review of Theoretical and Applied Aspects
Journal of Korean Society of Transportation, volume 11, issue 1, 1993, Pages 37~54
New Maximum Likelihood Estimation Algorithms for the Parameters of Generalized Gravity Model
Journal of Korean Society of Transportation, volume 11, issue 1, 1993, Pages 55~66
Toward Stochastic Dynamic Traffic Assignment Model: Development and Application Experiences
Journal of Korean Society of Transportation, volume 11, issue 1, 1993, Pages 67~86
A formulation of dynamic traffic assignment between multiple origins and single destination was first introduced in 1987 by Merchant and Nemhauser, and then expanded for multiple destination in the late 1980's (Carey, 1987). Based on behavioral choice theory which provides proper demand elasticities with respect to changes in policy variables, traffic phenomena can be analysed more realistically, especially in peak periods. However, algorithms for these models are not well developed so far(working with only small toy network) and solutions of these models are not unique. In this paper, a new model is developed which keeps the simplicity of static models, but provides the sensitivity of dynamic models with changes of O-D flows over time. It can be viewed as a joint departure time and route choice model, in the given time periods(6-7, 7-8, 8-9 and 9-10 am). Standard multinomial logit model has been used for simulating the choice behavior of destination, mode, route and departure time within a framework of the incremental network assignment model. The model developed is workable in a PC 386 with 175 traffic zones and 3581 links of Seoul and tested for evaluating the exclusive use of Namsan tunnel for HOV and the left-turn prohibition. Model's performance results and their statistical significance are also presented.
Green-Split Coordination Strategy in Oversaturated Signal System
Journal of Korean Society of Transportation, volume 11, issue 1, 1993, Pages 87~103
The subject this paper is the signal control strategy under oversaturated conditions. The nature of traffic control for oversaturation is essentially different from the standard control modes. While under non-saturated situation traffic control is needed for the sake of safety and efficiency, the throughput is essential under oversaturated conditions. Therefore berth objective and strategies differ. For an oversaturated stream the cycle time and the signal offset are thought to be of rather secondary importance. For this case the green split may well be the most important control variable to serve the excessive demand. Up to now, however, most efforts have concentrated on the strategy with the concept which lies just on the extension of Webster's. "Green-split Coordination Strategy for Over-Saturated Networks", presents newly contrived three types of strategies named Forward-coordination, Backward-coordination and Network-coordination respectively and describes the algorithms with the evaluations. The forward coordination strategy treats the forward wave of flow between two signals. The aim is to prevent the outbreak of queue due to the accumulation of temporary excess of demand in near-saturation or saturation flow. The backward coordination strategy treats the backward rave of flow between two signals. The goal is to prevent the waste of green time caused by the exit block at the upstream signal. for this purpose a feedback regulation is provided of the upstream green-split so that the inflow-outflow balance is kept zero. The resultant surplus of green time is alloted to other signal stages. Also here the examination is made of the appropriate value of the feedback control parameter. The network coordination strategy is operated to maximize the network throughput in a specific direction applying a bang-bang control at the bottleneck intersection. This is a type of intervenient control for policy reasons. For this strategy the green-split coordinations, particuarly the backward coordination, are essential as the tactical elements. In order to evaluate the preposed strategies those are compared with the latest existing strategy called saturation-degree-ratio control by the simulation experiments in an assumed 4
4 grid network. The results are satisfactory showing a 10-15% reduction in delays and a 15% increase in network capacity.