• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.13 no.3
• /
• pp.66-77
• /
• 2014

UTIS(Urban Traffic Information System) directly collects link travel time in urban area by using probe vehicles. Therefore it can estimate more accurate link travel speed compared to other traffic detection systems. However, UTIS includes some missing data caused by the lack of probe vehicles and RSEs on road network, system failures, and other factors. In this study, we suggest a new model, based on k-NN algorithm, for imputing missing data to provide more accurate travel time information. New imputation model is an adaptive k-NN which can flexibly adjust the number of nearest neighbors(NN) depending on the distribution of candidate objects. The evaluation result indicates that the new model successfully imputed missing speed data and significantly reduced the imputation error as compared with other models(ARIMA and etc). We have a plan to use the new imputation model improving traffic information service by applying UTIS Central Traffic Information Center.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.33 no.3
• /
• pp.1131-1142
• /
• 2013

This study aims to verify the applicability of TRANSIMS (TRansportion ANalysis SIMulation System) in interrupted traffic flow through calibration and validation process based on observation data; such as headway, traffic volume, speed, and travel time from Dalguberl Boulevard in Dae-gu metropolitan city. On this study, several micro-simulation parameters are derived from the calibration and validation process through performing a headway comparison and applying an ID back tracking methodology. As a result, it is figured out that actual circumstances of Korean roadway; for example, traffic volume per lane, speed, and travel time, can be applied on the TRANSIMS. Especially, it was possible to find out the influence of cell size parameter to traffic flow characteristic of simulation. However, it is hard to conclude that TRANSIMS is applicable to Korean roadway environment with studying particular target area. Therefore, additional studies; such as more case studies with various types of road, signal, and land use, will be required to localize TRANSIMS to Korea.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.6 no.3
• /
• pp.12-23
• /
• 2007

The purpose of this studγ if to understand problem of present bus scheduling system and to develop optimal bus scheduling model which improve bus passenger's degree of satisfaction(DOS) and bus company's operation efficiency at the same time. This study developed optimal bus scheduling model, which reflected bus passenger's degree of satisfaction(DOS), applied to existing model that summery of bus operation cost($C_o$), passenger queuing time cost($C_{pw}$) and passenger travel time cost($C_{pl}$). And optimal bus scheduling model which developed in this study is optimized that using LINGO program based on linear program. Also by using the general case in Busan, compare total cost of present bus scheduling system and existing scheduling model with total cost of optimal bus scheduling model which reflected bus passenger's degree of satisfaction(DOS).

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.35 no.4
• /
• pp.897-905
• /
• 2015

This research suggested the traffic signal calculation model of active transit signal priority using a shockwave model. Using this signal priority timing optimization model, the shockwave area is computed under the condition of Early Green and Green Extension among active transit signal priority techniques. This study suggested the speed estimation method of backward shockwave using average travel time and intersection passing time. A shockwave area change is calculated according to signal timing change of transit signal priority. Moreover, this signal timing calculation model could determine the optimal signal priority timings to minimize intersection delay of general vehicles. A micro simulation analysis using VISSIM and its user application model ComInterface was applied. This study checked that this model could calculate the signal timings to minimize intersection delay considering saturation condition of traffic flow. In case studies using an isolated intersection, this study checked that this model could improve general vehicle delay of more over ten percentage as compared with equality reduction strategy of non-priority phases. Recently, transit priority facilities are spreading such as tram, BRT and median bus lane in Korea. This research has an important significance in that the proposed priority model is a new methodology that improve operation efficiency of signal intersection.

• Journal of Korean Society of Transportation
• /
• v.22 no.2 s.73
• /
• pp.103-108
• /
• 2004

The motivation of this study comes from the problem recognition that the headway of passing vehicle in signalized intersections can not be merely determined by departing sequence. Traffic speed and headway data of passing vehicles in signalized intersection have been obtained by using magnetic detectors(NC 97) and detecting program, and the data was analyzed. Without special treatment, the model established on passing behavior of vehicles was meaningless from statistical view point. Hence, special treatments such as filtering (upper 85% offensive driver driven vehicle's) and log scaling of data were carried on. With this new data, meaningful model (where coefficient of determination is 0.91) was established. This model explained the fact that vehicle headway in signalized intersection is affected by speed and headway of previous vehicle and speed of itself.

• International Journal of Highway Engineering
• /
• v.9 no.4
• /
• pp.1-9
• /
• 2007

To decide the number of road lane is very important and related to the 30th design hourly factor in the design of transportation facilities. But, as the quantitative division of road types is difficult, most planner and designer for deciding the 30th design hourly factors have used the fixed values in our country. In this study, we have analyzed the time series property of the design hourly factors in national highways and developed the model capable of estimating the 30th design hourly factors using real data. The presented model is a simple regression model(DHV = K*AADT), which is applied to the division of road lanes(2 or 4 lanes) and the level of AADT(3 levels). As a results, the simple regression model have better performance than the existing method with respect to MAPE and $R^2$. Also, the variations of the 30th design hourly factors are small. The more traffic volume increase, the more the factors decrease. But, the limitation of this study is to use the exiting method estimating the values of the factors, it is subject to study hereafter.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.26 no.3D
• /
• pp.385-391
• /
• 2006

It is very important to make a decision for locating public facility site in a objectively way people in general agree with. This is because public facility affects not only daily life of people in there but also a regional development. This paper sets up a site selection model which utilize an accessibility theory and GIS spatial analysis techniques. This model has been applied to all the twelve alternatives of Chungnam Provincial Office (CPO) sites which are well known to the public. On the criterion of average access time from all the other areas in Chungnam Province, CH alternative is found to be the best one followed by CH/AS, AS alternatives. On the basis of total people-travel time CH/AS alternative turns out to be the best one followed by CH, AS alternatives. In conclusion top three best locations for CPO are CH and AS area where transportation facility are in good condition and population density is highest in Chungnam Province. This fact implies that a transportation accessibility and population density are the primary key in determining the location of public facility.

• Journal of Korean Society of Transportation
• /
• v.16 no.2
• /
• pp.177-195
• /
• 1998

지능형교통체계(ITS:Intellegent Transport System)의 구현을 위한 가장 중요한 요소중의 하나는 교통정보의 생성이다. 교통정보의 생성은 루프 검지기, 폐쇄회로(CCTV), probe 차량, 경찰, 통신원 등을 수집된 제보자료들을 분석 및 가공함으로써 이루어진다. 그러나 이들 수집원은 주어진 시간에 있어 모든 네트웍을 통해서 자료가 완전히 수집되어지는 것은 아니다. 즉, 특정 지역에 수집원이 몰려 있는 경우가 있는 반면, 전혀 수집되어지지 않는 지역이 발생할 수도 있다. 이러한 공간적인 불균형적 특성은 동시에 발생한 다량의 자료를 처리하는 기술과 자료가 수집되지 않은 지역에 대한 처리기술을 요하게 된다. 본 논문은 전술한 바와 같은 사항에 대하여 ITS의 진행 단계별로 드러날 수 있는 문제점을 검토하고, 자료통합에 대한 일반적인 개념을 우선 설명한다. 다음에 특정시각에 주어진 자료의 통합을 위해 퍼지선형회귀모형(fuzzy linear regression model)과 데이터 퓨전(data fusion)기법의 내용을 소개하고, 신뢰성있는 단일 교통정보생성을 위한 테이터 퓨전 알고리즘을 제시한다. 또한 제시된 알고리즘을 토대로 가상의 자료를 이용하여 적용가능 봉? 타진해 보았다. 제시되어진 알고리즘은 향후 교통정보 수집환경이 어느 정도 형성된다고 볼 때, 예측치와 실측자료간의 자료검증을 통하여 신뢰도를 가질 경우 보다 광범위하게 사용되어질 수 있을 것으로 판단된다.

• Journal of Korean Society of Transportation
• /
• v.25 no.1 s.94
• /
• pp.61-71
• /
• 2007

This study examines the determinants of location decisions for domestic skippers and identifies them with the aid of the location choice model The authors have used Korea's commodity flow survey collected by the inter-regional shippers as well as socio-economic indicators. The results suggest that the location of shippers depend on agglomeration economies, market size, and logistics activities. Finally. this study suggests the direction of locational Policies to help the Korean government with logistics-related policies.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.9 no.6
• /
• pp.63-82
• /
• 2010

In spite of continuous road construction, traffic congestion has been worsening by radical vehicle's increase and development of surroundings near expressway. Thus, the necessity of traffic management and the needs of provision of traffic information to drivers are raised. In order to solve traffic problems, such as traffic congestion, search for optimal congestion management technique and evaluation of the effect of optimal solution should be examined prior to practice of optimal alternative. However, existing traffic analysis model and simulation programs as tools to search and evaluate optimal alternative are not sufficient to reflect traffic flow characteristics, domestic road and traffic conditions and to link up to Freeway Traffic Management Systems (FTMS). Hence, to use existing traffic analysis and simulation tools are followed by hard work to need a lot of time and cost. Therefore, in this research, Expressway TRaffic Analysis Model (ExTRAM) based on Freeway Traffic Management Systems (FTMS) was developed to apply it into congestion management easily.