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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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Korean Society of Transportation
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Volume & Issues
Volume 27, Issue 6 - Dec 2009
Volume 27, Issue 5 - Oct 2009
Volume 27, Issue 4 - Aug 2009
Volume 27, Issue 3 - Jun 2009
Volume 27, Issue 2 - Apr 2009
Volume 27, Issue 1 - Feb 2009
Selecting the target year
Development of Methods to Evaluate Pedestrian Environments
Ji, U-Seok ;
Journal of Korean Society of Transportation, volume 27, issue 2, 2009, Pages 7~14
While much attention has been given to pedestrian environments recently, methods to evaluate their service level have not been fully developed yet. Although many kinds of pedestrian environment-related surveys and field studies are conducted, data are not systematically collected and accumulated due to the lack of consistent evaluation tools and methods. In this regard, it is necessary to develop reasonable evaluation methods for pedestrian environments. This paper suggests technical indices to evaluate pedestrian environments for a city. These indices provide useful ways to determine priorities to enhance pedestrian streets and also provide ways to compare cross sectional and time series changes of pedestrian environments. These indices therefore can be used as criteria for pedestrian environment planning and policy.
Modeling the Urban Railway Demand Estimation by Station Reflecting Station Access Area on Foot
Son, Ui-Yeong ; Kim, Jae-Yeong ; Jeong, Chang-Yong ; Lee, Jong-Hun ;
Journal of Korean Society of Transportation, volume 27, issue 2, 2009, Pages 15~22
There exist some limits when we forecast urban railway demand by traditional 4 step model. The first reason is that the model based on socioeconomic data by an administrative unit, 'Dong', yields a 'Dong' unit trip matrix. But a 'Dong' often has two or more stations. The second reason is that urban railway demand by station would be affected rather by station access area on foot than by a 'Dong' unit. So the model based on 'Dong' characteristic data have some inaccuracies in itself. Owing to the limits of the model based on 'Dong' unit data, there exits some difficulty in forecasting urban railway demand by station. So this paper studied two alternatives. The first is to forecast the demand by using the data of station access area on foot rather than 'Dong' unit data. This needs too much time and effort to collect data and analyse them, while the accuracy of the model didn't improve a lot. The second is to adjust the location of 'Dong' centroid and the length of centroid connector link. By this way we can reflect the characteristics of station access area on foot under traditional 4 step model. Comparing the expected demand to the observed data for each station, the result looks like very similar.
An Experimental Analysis of a Probabilistic DDHV Estimation Model
Jo, Jun-Han ; Kim, Seong-Ho ; No, Jeong-Hyeon ;
Journal of Korean Society of Transportation, volume 27, issue 2, 2009, Pages 23~34
This paper is described as an experimental analysis for the probabilistic directional design hour volume estimation. The main objective of this paper is to derive acceptable design rankings, PK factors, and PD factors. In order to determine an appropriate distribution for acceptable design rankings, 12 probability distribution functions were employed. The parameters were estimated based on the method of maximum likelihood. The goodness of fit test was performed with a Kolmogorov-Smirnov test. The Beta General distribution among the probability distributions was selected as an appropriate model for 2 lane roadways. On the other hand, the Weibull distribution is superior for 4 lanes. The method of the inverse cumulative distribution function came up with an acceptable design ranking of design for LOS D. An acceptable design ranking of 2 lanes is 190, while an acceptable design ranking for 4 lanes is 164. The PK factor and PD factor of 2 lanes was elicited for 0.119 (0.100-0.139) and 0.568 (0.545-0.590), respectively. On the other hand, the PK factor and PD factor for 4 lanes was elicited as 0.106 (0.097-0.114) and 0.571 (0.544-0.598), respectively.
Evaluation Index for the Supply Levels of Pedestrian Facilities in Residential Area Planning
Choe, Jae-Seong ; Hwang, Gyeong-Seong ; Kim, Sang-Yeop ; Jang, Yeong-Su ; Park, Sin-Won ;
Journal of Korean Society of Transportation, volume 27, issue 2, 2009, Pages 35~46
This paper presents an evaluation index for the supply levels of pedestrian facilities in residential area planning. The pedestrian facility supply levels reveal the quality of a residential area, and can be associated with the resident living standards and satisfaction, pedestrian safety levels, and the effectiveness of the construction cost. This research conducted multifaceted procedures for the index development, and these procedures start first by identifying dominant influencing factors on pedestrian travel demand by reviewing the final reports of site planning in more than eight already-completed residential development sites. Second, based on the Space Syntax model, which was initially developed in the UK by establishing statistical relationships among an integration index, population size (persons/day), and the total development area, this research formulated a set of pedestrian demand estimation models. Then these models were utilized in forming a pedestrian facility supply index by integrating the new models and their results with the available accepted practice in the residential planning sector. This was necessary because planners want to understand the total supply level of pedestrian facilities in a residential area during the initial design stage. Finally, to test the model validity in satisfying pedestrian satisfaction, the research included a resident satisfaction interview, and it was revealed that the evaluation index developed in this research could provide planners and engineers with more promising results. It is therefore anticipated that this research can be of service when designing pedestrian facilities in future residential area planning and design activities.
Correction of Erroneous Individual Vehicle Speed Data Using Locally Weighted Regression (LWR)
Im, Hui-Seop ; O, Cheol ; Park, Jun-Hyeong ; Lee, Geon-U ;
Journal of Korean Society of Transportation, volume 27, issue 2, 2009, Pages 47~56
Effective detection and correction of outliers of raw traffic data collected from the field is of keen interest because reliable traffic information is highly dependent on the quality of raw data. Global positioning system (GPS) based traffic surveillance systems are capable of producing individual vehicle speeds that are invaluable for various traffic management and information strategies. This study proposed a locally weighted regression (LWR) based filtering method for individual vehicle speed data. An important feature of this study was to propose a technique to generate synthetic outliers for more systematic evaluation of the proposed method. It was identified by performance evaluations that the proposed LWR-based method outperformed an exponential smoothing. The proposed method is expected to be effectively utilized for filtering out raw individual vehicle speed data.
Relationships between Diversion Rates and Traffic Conditions on Expressways
Choe, Yun-Hyeok ; Choe, Gi-Ju ; Go, Han-Geom ;
Journal of Korean Society of Transportation, volume 27, issue 2, 2009, Pages 57~71
Due to increasing interest in dispersion of traffic flows through providing traffic information, there has been much research of driver behavior and effectiveness of diversion. In this paper the authors intend to analyze how a diversion was determined and its effects through correlation analysis between diversion rates estimated by actual surveys and the traffic conditions. Through speed-flow analysis, the diversion mechanism was found. When travel speed decreased, detour volume increased. Then when the traffic volume was decreased through an increase of diversion and traffic conditions got better, the detour volume decreased again. In addition, the authors found negative correlation between the diversion rate and travel speed through correlation analysis. It shows that there were various relationships between diversion rates and traffic conditions according to congestion level and direction of traffic. Finally, it is suggested that the regression equation for calculating the diversion rate with the traffic flows, travel speed, and travel time as variables has a coefficient of determination of 38.5%. It means that traffic conditions on expressways take about 40% of driver's decision-making for diversion.
The Standardization of Location Data for Location-based Services
Jeong, Yeon-Jeong ; Park, Sin-Hyeong ; Park, Chang-Ho ; Kim, Chang-Ho ;
Journal of Korean Society of Transportation, volume 27, issue 2, 2009, Pages 73~82
Location-based concierge services (LBCS) are considered to be one of the main service functions provided in a city in ubiquitous technology spaces. A "Ubiquitous City" is defined as a city in which both public and private services can be delivered and received anywhere and anytime. One of the key elements that make location-based concierge services successful is the interoperability of location data. Currently, several existing technologies could provide LBCS including car navigation services and ubiquitous computing. However, lack of standardized structure for location data makes it impossible for heterogeneous technologies to be able to deliver uniform LBCS. The purpose of this paper is to develop standardized locational data structure so that heterogeneous technologies could provide efficient LBCS to all users of the various transportation modes.
A Study on Forecasting Air Transport Demand between South and North Korea
Lee, Yeong-Hyeok ; Ryu, Min-Yeong ; Choe, Seong-Ho ;
Journal of Korean Society of Transportation, volume 27, issue 2, 2009, Pages 83~91
This paper aims to predict air passenger and air freight demands in the air routes between South and North Korea. The air demands will be fostered by the visitors of Pyeongyang and Baekdu Mountain, whose forecasts will be used for supplying the air traffic services necessary for the active exchange and cooperation between South and North Korea in the future. The authors use the tool of regression analysis under the assumption of epoch-making progress in demand for aviation in accordance with the exchange and cooperation scenario between South and North Korea. After predicting the total number of travelers through regression analysis, the authors applied the share of air passengers among total travelers in order to predict the number of air passengers. Finally, the number of flights of each airport and route were forecasted by including the air freight, estimated from the number of air passengers.
The Development of Neural Network Model to Improve the Reliability of the Demand/Effort Model for Evaluating Highway Safety
Jeong, Bong-Jo ; Gang, Jae-Su ; Jang, Myeong-Sun ;
Journal of Korean Society of Transportation, volume 27, issue 2, 2009, Pages 95~105
Traffic accidents on highways are likely to happen when there is an imbalance in the complex relationships among key elements such as road geometries, driver related factors, and mechanical performances. The Demand-Effort Model (DEM), which evaluates highway safety, can be explained by the imbalance, which occurs when the level of demand of the driver's attention to the road environment exceeds that of the response from the driver. This study suggests a new model that improves the reliability of the current DEM through the reinterpretation on the physiological signals with the help of the Neural Network Model (NNM). The data were collected from 149 subjects, who drove a test vehicle on the Yongdong, Honam, and Seohaean Expressways in Korea. Three important results could be drawn from the recursive tests as follows; (1) Only 5 out of 10 parameters on the physiological signals which are currently used were proven to be meaningful through the Normality Test, Cluster Analysis, and Mann-Whitney Analysis. (2) The revised DEM, which internally uses the NNM, showed more reliable results than existing DEM. Group 1, which is based on the new DEM showed 80.0% of accuracy in measuring the level of driver's efforts, however, that of Group 2 based on the current DEM was 74.3%. (3) Field tests on the Honam Expressway showed lower 'type II error' with the new DEM (40.5%) than the old DEM (58.8%). The DEM is designed as a quick and easy way to determine highway safety prior to the minute road safety audit (RSA) by a professional audit team. Then a new DEM, which is based on the NNM, needs to be considered since it showed higher reliability and lower error.
The Influence of Traffic Islands on Pedestrian Safety
Lee, Su-Beom ; Kim, Myeong-Suk ; Jang, Il-Jun ; Kim, Jang-Uk ;
Journal of Korean Society of Transportation, volume 27, issue 2, 2009, Pages 107~115
Traffic islands were introduced for drivers and pedestrians to use the road in a safe and orderly way and were also a specified zone between traffic lanes to divide conflicting traffic flows and to provide pedestrian refuge. However, existing research and relevant standards described its purpose and effects only but not a safety standard to decide whether the traffic island warranted. This study was to introduce a parameter which had a high relationship with accidents by analyzing road and traffic conditions and traffic accident data at urban intersections. Based on the relationship between the parameter and the traffic accidents at the intersection, a pedestrian accident probability model was made by using a logit model. In addition, the study reviewed a pedestrian accident probability corresponding to traffic volume and size of the intersection during design of the intersection and then suggested the effectiveness of the traffic island in terms of traffic safety. In conclusion, when a large-scale intersection has significant traffic volumes, a high probability of traffic island-induced pedestrian accidents appears, while in the case of small volumes, the probability is low. Targeted design and operations of a traffic islands is necessary, because its introduction itself does not enhance pedestrian safety in all cases at all intersections. This study can be a useful reference for further development to set up a scheme of the traffic islands in terms of traffic safety.
Development of Predicting Models of the Operating Speed and Operating environment Satisfaction Model in Expressways
Kim, Jang-Uk ; Jang, Il-Jun ; Kim, Jeong-Hyeon ; Lee, Su-Beom ;
Journal of Korean Society of Transportation, volume 27, issue 2, 2009, Pages 117~131
When most drivers take to the freeway, they don't necessarily pay attention to the geometric design. They expect proper design by depending on their own senses and recognition. When they evaluate the features of traveling on the freeway, they can think differently than engineers. The design needs to predict the exact speed of the driver to satisfy the driver's expectation, safety, pleasure and so on. This study categorized the factors influencing the speed of six freeways considering geometric and operational features to make a prediction model of speed. The model used multiple regression with these factors and produced statically appropriate results. This study utilized the principle component analysis and the quantification II analysis based on the image data of the satisfaction of the traveling environment collected through individual interviews. As a result, this study found the factors of satisfaction in a traveling environment. It made a satisfaction model of the traveling environment on freeways considering the change of driver's actual recognition and societal recognition using structural equations and the quantification II theory. Through the model made in this study, This model can present not only qualitative factors like satisfaction of traveling environment on freeways, but also the quantitative elements like speed. What is important is the evaluation of features of traveling on freeways reflected in the recognition and traffic environment felt by drivers.
Travel Time Forecasting in an Interrupted Traffic Flow by adopting Historical Profile and Time-Space Data Fusion
Yeo, Tae-Dong ; Han, Gyeong-Su ; Bae, Sang-Hun ;
Journal of Korean Society of Transportation, volume 27, issue 2, 2009, Pages 133~144
In Korea, the ITS project has been progressed to improve traffic mobility and safety. Further, it is to relieve traffic jam by supply real time travel information for drivers and to promote traffic convenience and safety. It is important that the traffic information is provided accurately. This study was conducted outlier elimination and missing data adjustment to improve accuracy of raw data. A method for raise reliability of travel time prediction information was presented. We developed Historical Profile model and adjustment formula to reflect quality of interrupted flow. We predicted travel time by developed Historical Profile model and adjustment formula and verified by comparison between developed model and existing model such as Neural Network model and Kalman Filter model. The results of comparative analysis clarified that developed model and Karlman Filter model similarity predicted in general situation but developed model was more accurate than other models in incident situation.
Comparison of Area Pricing and Cordon Pricing in General Equilibrium Models
Yu, Sang-Gyun ; Jeong, Chang-Mu ; Lee, Hyeok-Ju ;
Journal of Korean Society of Transportation, volume 27, issue 2, 2009, Pages 145~155
This paper compares the relative performances of area and cordon tolls as opposed to the first-best congestion tolls with respect to alleviation of traffic congestion and social welfare. The comparison is done in the monocentric city where all the jobs are located at the city center. The study shows that the size of charging zones is similar in the two second-bests, but that the optimal toll level is higher in area pricing than in cordon pricing. Area pricing schemes turn out to perform better than cordon pricing schemes as measured by average speeds and daily average travel time. Accordingly, the former is shown to increase the social welfare more than the latter. In the case of the cordon tolls, the residents at the charging zones are exempted from the tolls. In this way, cordon tolls invite people into the most congested areas over the optimal level while partially negating the whole spirit of the congestion tolls.
Utility Maximization, The Shapes of the Indifference Curve on the Characteristic Space and its Estimation: A Theoretical Approach
Kim, Jong-Seok ;
Journal of Korean Society of Transportation, volume 27, issue 2, 2009, Pages 157~168
The random utility theory and the multinomial logit model (including a more recent variant--the mixed multinomial logit) derived from it have constituted a back bone for theoretical and empirical analyses of various travel demand features including mode choice. In their empirical applications, however, it is customary to specify random utilities which are linear in modal attributes such as time and cost, and in socio-economic variables. The linearity helps easy derivation of important information such as value of travel time savings by calculating marginal rate of substitution between time and cost. In this paper the author focuses on the very linearity of the random utilities. Taking into account the fact that the mode chooser is also labour supplier, commodity consumer as well as leisure-seeker, the author sets up a maximization model of the traveller, which encompasses various economic activities of the traveller. The author derive from the model the indifference curve defined on the space of modal attributes, time and cost and investigate under what conditions the random utility of the traveller becomes linear. It turns out that there exist the conditions under which the random utility is really linear in modal attributes, but the property does not hold when the traveller has a corner solution on the space of modal attributes, or when the primary utility function of the traveller is directly affected by labour provided and/or the travel time itself. As a corollary of the analysis, a random utility is suggested, approximated up to the second order of the variables involved for empirical studies of the field.
A Study on the Association of Commuting Behavior with Individual Health
Seong, Hyeon-Gon ; Sin, Gi-Suk ; No, Jeong-Hyeon ;
Journal of Korean Society of Transportation, volume 27, issue 2, 2009, Pages 169~178
This study is aimed at identifying the association of commuting behavior with health for workers in the Korea Capital Region. The study surveyed a total of 1,285 commuters whose major work is deskwork-oriented; the authors obtained their health status on body form, blood pressure and cholesterol as well as their commuting behavior. The measures of the latter were comprised of a main commuting mode, a use term, out-of-vehicle time, total travel time, transit transfer, and alternative mode in order to identify the amount of physical activity obtained through commuting behavior. The results indicate that non-automobile commuters are positively associated to improve their health status, as compared to car commuters. Specifically, bus commuters and walkers had decreased weight, blood pressure, and cholesterol, while rail commuters are only correlated to relieving cholesterol. In addition, the measures for health are improved as out-of-vehicle time increases. For commuters who drive to work, their health status tends to be worse.
A Study on the Preemption Control Strategies Considering Queue Length Constraints
Lee, Jae-Hyeong ; Lee, Sang-Su ; O, Yeong-Tae ;
Journal of Korean Society of Transportation, volume 27, issue 2, 2009, Pages 179~187
Currently, the signalized intersections in Korea are operated without providing an emergency vehicle preemption control strategy. Thus, it might threaten the safety of the pedestrians and drivers on highways when an emergency vehicle faces congested traffic conditions. The existing preemption control is activated when an emergency vehicle is detected along a path. This enables emergency vehicles to progress uninterrupted, but it also increases the delay of other vehicles. In this paper, a revised preemption control strategy considering queue length restrictions is proposed to make both a progressive movement of an emergency vehicle and reduce delay of other vehicles simultaneously. By applying the preemption control strategy through a simulation study, it was shown that delay of an emergency vehicle decreased to 44.3%-96.1% and speed increased to 8.8%-42.0% in all 9 cases as compared with a conventional signal control. The existing preemption control is superior for oversaturated conditions (v/c >1.0) or a link length less than 200m. However, the preemption control considering queue length constraints shows better performance than the existing preemption control when the v/c is less than 0.8 and a link length is longer than 500m.
Relationship between Traffic Accidents of Elderly Pedestrians and Barrier-Free Facilities in the Case of Cheongju
Park, Byeong-Ho ; Yang, Jeong-Mo ; In, Byeong-Cheol ;
Journal of Korean Society of Transportation, volume 27, issue 2, 2009, Pages 189~197
The purpose of this study is to analyze the relationships between the traffic accidents of elderly pedestrians and barrier-free facilities in the case of Cheongju. First, many accidents of elderly pedestrians were determined to occur in the road and during crossing. Second, the correlation analysis shows that the paving conditions, guiding blocks and embossed blocks have impacts on elderly safety. Finally, the logistic regression model, which is statistically significant (chi-square =0.000, Nagelkerke =0.198), was developed, and includes the paving conditions, bollards, audible signals and remaining time signs as the independent variables. The variables, with the exception of the existence of bollards, are all analyzed to have positive impacts to elderly safety.
A Study on the Development of an Economic Efficiency Model Considering Vehicle Operating Cost Properties of Signalized Intersections
Byeon, Eun-A ; Kim, Yeong-Chan ; An, So-Yeong ; Go, Gwang-Deok ; Yun, Su-Yeong ;
Journal of Korean Society of Transportation, volume 27, issue 2, 2009, Pages 199~206
In relation with economical efficiency analysis on investment evaluation of transportation system, among vehicle operating cost saving benefit that is applied to general preliminary assessment guidelines and investment evaluation guidelines, oil expense calculated data which concentrated and analyze on the relationship between oil consumption amount on running state and running speed. For uninterrupted flow which does not have stopped delay due to traffic signal, consideration for reduction benefit is possible due to the changes of running speed and travel time however, for interrupted flow which the stopping occurs due to signal control on actual signal intersection has no consideration for stopping delay time reduction and stopping rate improvement thus reflection of reality on improved effect analysis is difficult. Therefore, this research makes a framework to analyze benefits that reflects the features of signalized intersections by benefits associated with decrease of stopping delay time with existing research and developing vehicle operating cost calculation model formula. Vehicle operating cost has been redefined considering the stopping delay time by applying the oil consumption amount at idling and the economical benefit between conventional model and newly developed model when applied for the optimization of traffic signal system on the two roads in Seosan city has been analyzed comparative. While the importance of traffic system maintenance is being emphasized due to the increase of congested areas on roads, it is expected to assist in more realistic economical analysis which reflect the delay improvement through the presentation of an economic analysis model that considers the features of signalized intersections in signal optimization system improvements and effect analysis of congestion improvement projects`.
A Methodology for Providing More Reliable Traffic Safety Warning Information based on Positive Guidance Techniques
Kim, Jun-Hyeong ; O, Cheol ; O, Ju-Taek ;
Journal of Korean Society of Transportation, volume 27, issue 2, 2009, Pages 207~214
This study proposed an advanced warning information system based on real-time traffic conflict analysis. An algorithm to detect and analyze unsafe traffic events associated with car-following and lane-changes using individual vehicle trajectories was developed. A positive guidance procedure was adopted to provide warning information to alert drivers to hazardous traffic conditions derived from the outcomes of the algorithm. In addition, autoregressive integrated moving average (ARIMA) analyses were conducted to investigate the predictability of warning information for the enhancement of information reliability.