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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of Korean Society of Transportation
Journal Basic Information
Journal DOI :
Korean Society of Transportation
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Volume & Issues
Volume 25, Issue 6 - Dec 2007
Volume 25, Issue 5 - Oct 2007
Volume 25, Issue 4 - Aug 2007
Volume 25, Issue 3 - Jun 2007
Volume 25, Issue 2 - Apr 2007
Volume 25, Issue 1 - Feb 2007
Selecting the target year
A Study of Posted Speeds on Freeway Exits and Entrances
Im, Geun-Ho ; Kim, Hong-Sang ; Choe, Hyeon-Seok ;
Journal of Korean Society of Transportation, volume 25, issue 4, 2007, Pages 7~19
The purpose of posted speeds is to provide a speed that ensures the safety of vehicle flow according to given road situations. Because of this, posted speeds must be carefully examined, and posted speeds at freeway exits and entrances in particular should consider car characteristics. Posted speeds at freeway exits and entrances must take changing speeds due to curve radiuses into consideration and in this study, an 85th percentile speed becomes the most important element to consider. When it is considered that most traffic accidents occur because of variations in speed between cars, posted speeds should be set after considering car traveling characteristics. Within these dimensions, instead of putting significance on an upper direction regulation or lower direction regulation, speed distributions which fit to the characteristics of each road should be fully considered. Accordingly, this study evaluated appropriate posted speeds that will reduce the dangers of traffic accidents through posted speed regulations of roads now in operation by offering a posted speed setting method theory, using entries at Yangji, Yongin, and Cheongwon interchanges as subjects.
Validation and Correction of Expanded O/D with Link Observed Traffic Volumes at Screenlines
Kim, Ik-Gi ; Yun, Ji-Yeong ; Chu, Sang-Ho ;
Journal of Korean Society of Transportation, volume 25, issue 4, 2007, Pages 21~32
The households to be surveyed are usually huge number at the level of a city or metropolitan survey, not to mention a nationwide travel survey. Therefore, household travel surveys to figure out true origin-destination (O/D) trip patterns (population O/D) are conducted through a sampling method rather than by surveying all of the population in the system. Therefore, the population O/D pattern can only be estimated by expanding the sampled O/D patterns to the population. It is very difficult to avoid the errors involved in the process of sampling, surveying and expanding O/D data. In order to minimize such errors while estimating the true O/D patterns of the population, the validation and adjustment process should employed by doing a comparison between the expanded sample O/D data and observed link traffic volumes. This study suggests a method of validation and adjustment of the expanded sample O/D data by comparing observed link volumes at several screenlines. The study also suggests a practical technique to modify O/D pairs which are excluded in the screenline validation process by comparing observed traffic volume with the results of traffic assignment analysis. An empirical study was also conducted as an example applying the suggested methods of validation and adjustment with Korea's nationwide O/D data and highway network.
A Preliminary Study on Presentation Techniques of Traffic Guide Maps
Kim, Dong-Nyeong ; Park, Jeong-Min ;
Journal of Korean Society of Transportation, volume 25, issue 4, 2007, Pages 33~42
This study analyzes presentation methods of traffic guide maps to guide drivers easily and correctly to their destinations on complex road networks. The problems of Korea's guidance systems were analyzed and domestic and international road guide maps were compared. This study includes the problems of road number discernment, such as the sizes, colors and marking intervals on the map. The widths and colors of different hierarchical roads were evaluated. The indices, enlarged downtown maps and uncertainty of grade separation on the map were analyzed and the solutions were also provided.
Road Safety Strategy Corresponding to Development: The Need for Participation of Medical Professionals
Lee, Sang-Wan ;
Journal of Korean Society of Transportation, volume 25, issue 4, 2007, Pages 43~56
Since the 1970s, along with an increasing number of motor vehicles in Korea, road crashes and casualties started to increase and eventually resulted in a serious public health problem starting from the beginning of the 1990s. Government authorities, however, have been not so proactive with reducing road crashes and injuries as well as deaths and have been reluctant to design effective safety strategies that could be established in collaboration with relevant multidisciplinary professionals. This paper aims at showing the status of road safety versus socioeconomic development in Korea and highlighting safety strategies that particularly need the participation of medical professionals. Six indicators to measure socioeconomic development and two indices for road safety were examined and international comparisons were made, finding road safety in Korea has been not corresponding to its level of development. The imbalance between socioeconomic development and road safety will certainly require the government authorities to look for effective safety strategies necessitating cooperation and collaboration with relevant experts including medical professionals. To make a provision for such needs in the near future, studies and experiences previously reported in the literature of traffic medicine and the world congresses of the International Traffic Medicine Association since 1984 were reviewed and categorized to focus on the strategies as well as measures that would be most effective in a mid-income country such as Korea.
Benefit Evaluation for Traffic Transfer System using Contingent Valuation Method in Tourist Resort
Lee, Byeong-Ju ; Seo, Im-Gi ; NamGung, Mun ;
Journal of Korean Society of Transportation, volume 25, issue 4, 2007, Pages 57~66
According to the rapid economic growth and the escalation of recreational tourism activities due to the change of job and working patterns, currently various traffic problems often occur in tourist areas. As tourist traffic, contrary to general traffic, is not regional but rather from outside the area of interest, it is hard to grasp the traffic situation surrounding the tourist area. Furthermore, since the traffic is concentrated during a limited tourist season, it is difficult to examine and solve the problem. In this study, in order to test the feasibility of introducing a traffic transfer system to reduce congestion in tourist areas, the authors considered the differences in traffic congestion between typical and tourist seasons and designed a willingness to pay model. The willingness to pay amount for a shuttle bus fare is assumed as 1,430 Won and 1,650 Won is assumed for a transfer parking charge. These amounts were slightly above the current bus fare in the study area, but many people thought that the introduction of a traffic transfer system would help to relieve the traffic congestion approaching the tourist area and to develop tourism resources. As the willingness to pay appeared high from the persons used in this study, it was indirectly confirmed that the introduction of a traffic transfer system would be a step in the right direction.
A study on Pedestrian Accident Reconstruction Models: Comparison and Improvement
Jo, Jeong-Il ; O, Cheol ; Kim, Nam-Il ; Jang, Myeong-Sun ;
Journal of Korean Society of Transportation, volume 25, issue 4, 2007, Pages 69~77
This study presents comparison results for pedestrian accident reconstruction models representing the relationship between collision speed and horizontal distance that a body travels while falling and sliding. A set of 49 reliable pedestrian accident cases are applied to compare the existing reconstruction models. In addition, the authors investigate the effects of a set of parameters associated with the effects of the frontal shape of a vehicle on the horizontal distance a pedestrian travels while falling and sliding. It has been revealed that the length of the bumper is the most dominant factor to affect the horizontal distance of pedestrian travel after collision. Further analyses utilizing more accident data need to conducted to develop a more accurate and reliable reconstruction model.
Determination of Minimum Spacing between Off-ramp Terminus and Intersection Considering the Influence of Adjacent Signalized Intersections
Kim, Sang-Gu ; Sim, Dae-Yeong ; Heo, Du-Wan ;
Journal of Korean Society of Transportation, volume 25, issue 4, 2007, Pages 79~87
The interchanges of urban freeways have many problems with traffic operation due to high off-ramp flows and frequent congestion at adjacent intersections. The flow exiting from off-ramps is affected by the operational status and traffic volume conditions of the nearest signalized intersection. As a result, off-ramp flow cannot exit and the queue backs up the freeway mainline when queues from the signalized intersection form up to the junction of the off-ramp and street. The spacing between an off-ramp and an adjacent intersection is likely to determine the traffic conditions at the adjacent intersection. However, the current design guidelines do not consider such a factor. This study is to develop a model calculating the spacing between off-ramps and adjacent intersections considering the signal, traffic, and road conditions. The variables affecting the model in this study are effective green time (g/C), volume-capacity ratio (v/c), the number of lanes, and off-ramp volume. Various scenarios are designed to represent the effects of the variables and the road networks are constructed using VISSIM, which is a common traffic micro-simulation software package. The queue length is derived from VISSIM and this length is considered as the recommended spacing between the off-ramp and the adjacent intersection. Through the simulation analysis, regression models are developed to calculate the queue length reflecting the various conditions such as signals, traffic, and road configurations. The developed model can be used to create road design guidelines to determine the location of off-ramps in the planning stage.
Main Psychological Factors Contributing to Aggressive Driving
Sin, Yong-Gyun ; Ryu, Jun-Beom ; Gang, Su-Cheol ;
Journal of Korean Society of Transportation, volume 25, issue 4, 2007, Pages 89~98
Nowadays, aggressive driving is a common driving behavior and it is raised as a dangerous factor for both drivers and passengers. However, it is hard to find studies on aggressive driving in Korea, and even the definition of aggressive behavior is not clearly explained. In this study, the term "aggressive behavior" is defined based on previous studies, and the significance of several psycho-social factors which affect aggressive driving were verified with the 'habit' factor from the Theory of Planned Behavior (TPB). In the pilot study, domestic drivers reported that aggressive behaviors included speeding, traffic light signal violation, and improper passing (cutting drivers off when passing). In this study, controlling the demographic characteristics of these three aggressive behaviors, the authors explored the relationship of the behaviors with TPB factors such as the habit factor. Consequently, in the case of drivers' intentions for speeding and traffic light signal violations, subjective norm, perceived behavioral controllability, and habit were significant factors. In the case of intentions for improper passing, only perceived behavioral controllability and habit were significant. In speeding behavior and traffic light signal violations, only habit was significant besides intention; however, in improper passing, both perceived behavioral controllability and habit were significant besides intention. The authors also tested an alternative model including TPB and habit factors for three types of aggressive driving. Finally, there are several implications for a possible intervention program for aggressive driving, though there are some limitations of the study.
Elastic Demand Stochastic User Equilibrium Assignment Based on a Dynamic System
Im, Yong-Taek ;
Journal of Korean Society of Transportation, volume 25, issue 4, 2007, Pages 99~108
This paper presents an elastic demand stochastic user equilibrium traffic assignment that could not be easily tackled. The elastic demand coupled with a travel performance function is known to converge to a supply-demand equilibrium, where a stochastic user equilibrium (SUE) is obtained. SUE is the state in which all equivalent path costs are equal, and thus no user can reduce his perceived travel cost. The elastic demand SUE traffic assignment can be formulated based on a dynamic system, which is a means of describing how one state develops into another state over the course of time. Traditionally it has been used for control engineering, but it is also useful for transportation problems in that it can describe time-variant traffic movements. Through the Lyapunov Function Theorem, the author proves that the model has a stable solution and confirms it with a numerical example.
Modelling Missing Traffic Volume Data using Circular Probability Distribution
Kim, Hyeon-Seok ; Im, Gang-Won ; Lee, Yeong-In ; Nam, Du-Hui ;
Journal of Korean Society of Transportation, volume 25, issue 4, 2007, Pages 109~121
In this study, an imputation model using circular probability distribution was developed in order to overcome problems of missing data from a traffic survey. The existing ad-hoc or heuristic, model-based and algorithm-based imputation techniques were reviewed through previous studies, and then their limitations for imputing missing traffic volume data were revealed. The statistical computing language 'R' was employed for model construction, and a mixture of von Mises probability distribution, which is classified as symmetric, and unimodal circular probability were finally fitted on the basis of traffic volume data at survey stations in urban and rural areas, respectively. The circular probability distribution model largely proved to outperform a dummy variable regression model in regards to various evaluation conditions. It turned out that circular probability distribution models depict circularity of hourly volumes well and are very cost-effective and robust to changes in missing mechanisms.
Analysis on Efficiency of Hierarchical Structure for a Grid Transit Network
Park, Jun-Sik ; Go, Seung-Yeong ; Jeon, Gyeong-Su ;
Journal of Korean Society of Transportation, volume 25, issue 4, 2007, Pages 123~133
This study analyzed whether a transit network with hierarchy is efficient or not, and if transit network hierarchy has cost efficiency, then which condition guarantees the efficiency of the transit network hierarchy. The authors modeled the total cost of the transit network and suggested the conditions in which the transit network hierarchy has cost efficiency through comparing the cost of the transit network with and without hierarchy. The efficiency of transit network hierarchy is guaranteed when the travel cost savings induced by using a higher hierarchy transit network is larger than the increasing non-travel cost, which is the sum of access cost, waiting cost, and operating cost, induced by the introduction of a higher hierarchy transit network. This result is consistent with common sense and with the concept of cost and benefit analysis. If a passenger traveling within the area divided by a higher hierarchy transit network uses only a lower hierarchy transit network and the passenger traveling out of the area divided by the higher hierarchy transit network uses both lower and higher hierarchy transit networks, the travel demand using the higher hierarchy transit network is inversely proportional to the square of the line spacing. This means that the transit network becomes more efficient and small increases of travel demand guarantee the efficiency of the transit network hierarchy as the connectivity of the network becomes higher. This result shows that transit networks have economies of aggregation. This study is the first analytical research on transit network hierarchy and is expected to be a basis for numerical research. However, numerical research should complement this study, since analytical research has some limitations for considering a real network.