• Journal of Korean Society of Transportation
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• v.27 no.6
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• pp.119-127
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• 2009

It has been known that bus route and company related characteristics have influences on punctuality, but fewer research have been conducted. Independent variables used in this study were selected using correlation analysis, and OLS(Ordinary Least Square) and HLM(Hierarchical Linear Model) were employed to identify factors affecting bus punctuality(headway deviation). The results showed that ICC(intraclass Correlation Coefficient) is 0.10, indicating that hierarchical linear models are more adequate for these data because there is effective variation in the subjects between companies. Punctuality was found to be negatively associated with the number of vehicles, the number of persons per vehicle, and total travel time. On the other hand, average headway and company size have a positive relationship with punctuality. Therefore, the number of vehicles per route, average headway, and the number of vehicles managed by a company should be considered for more accurately evaluating the management of piunctuality.

• Journal of Korean Society of Transportation
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• v.20 no.1
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• pp.121-130
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• 2002

Purpose of this paper is proposing technical evaluation method for safety on two-lane rural highways, this method can contribute to an establishment of the safety evaluation criteria and eventually contribute to the highway safety. In this study, accident data and field data(grade, radius, speed factor) are collected and are analyzed. And new technical evaluation method is proposed by problem in review of existent methods and analysis result. Property of new method is verified by comparing with existent one. Following are results of this study. 1) Proposed technical evaluation method is Proposed by using difference of speed variance and difference of acceleration. 2) In range of field survey, proposed method is more proper than existent one by comparing. 3) Headways under 6 second affect speed of next vehicle. 4) A point with the lowest speed in curve is placed about 35m from the beginning point. 5) Correlation of speed variance and severity of highway(EPDO) is statistically significant. For using proposed method, more tests are needed on other locations with various geometries. Moreover, advanced study is needed about classifying and giving the weight of each criterion.

• Journal of Korean Society of Transportation
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• v.23 no.2
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• pp.151-160
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• 2005

In case of public transit such as bus system, the probability concept is used to evaluate the Level-of-Service of the operations. And each levels could be classified according to the linear probability value. (TCQSM: Transit Capacity and Quality of Service Manual-2nd Edition, TRB, Washington DC., 2003) In this case, the drivers or passengers wouldn't think that the service level isn't equivalent to the linear probability value. Thus the linear probability value doesn't exactly reflect the service level. This study shows the problems of using the linear probability value in classifying the service level through the case of evaluation of bus operation's punctuality, presented in TCQSM. To make up for the problems of such case, two methodologies are presented in this study. The method of determining Level-of-Service criteria using probability density of headway variation's distribution, presented in this paper, adequately reflects passenger's expected waiting time. According to the application result to real bus operation data, it tis better than the method of TCQSM to evaluate the reliability of bus operations. However further research about the relations between utility difference and passenger feeling of service level in necessary to apply the method that uses the utility function. It remains as the limitation of this paper.