• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.4
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• pp.1-13
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• 2009

VMS(Variable Message Sign) which makes the traffic flow smooth by providing traffic information to road users in real-time has been being installed or operated on the road as part of the detailed ITS system. However, some problems were found as a result of survey on express way currently. In the part of the phase operation, the message interpretation time wasn't defined so that the phase operation was difficult. In the part of the information service, not considering characteristic of the VMS section caused the confusion to drivers. In the part of the message exposure, font, alignment, conversion and composition of the information were not consistent and use of superfluous words and inconsistent use of word having the same meaning brought about the problem on information communication This study established the detailed exposure method based on instructions relative to VMS operation. The method established by defining the number of appropriate phase and setting required function of each individual VMS installation location. The method is as follow. the font type is the GULIM, the message conversion method is simple conversion method, the alignment method is centering alignment method and the color is defined according to each situation. In this study, the preference survey was performed to review the validity of the proposed improvement through the common driver. The results were similar with the pre-study except for the font type. This study established the detailed exposure method based on instructions relative to VMS operation. The method established by defining the number of appropriate phase and setting required function of individual VMS installation location. For the evaluation of status and improvement, preference survey of ordinary drivers and statistics analysis was carried.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.14 no.2
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• pp.54-68
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• 2015

The advantage of electric taxies is that people who are not familiar with electric vehicle(EV) can have easily experience to ride EV. So, EV taxi would be a reasonable strategy for triggering EV market expansion. However, the EV taxi can be adopted by taxi companies with financial benefits. Therefore the feasibility study should be required by analyzing the cost with the points of view of the taxi company. In this study we suggested the methodology for feasibility study of the EV taxi based on the real taxi data and presented political implication. According to the study result, EV taxies could have economic value under the specific conditions such that the government subsidy is added to the purchase price of the vehicle. Also, the charging time should be used as drivers' rest time or mealtime in order not to consider the loss cost. We suggest that the new feasibility study which compares an EV taxi with other alternative vehicles such as PHEV or with an old EV taxi is needed as the future works.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.5
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• pp.77-87
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• 2018

Traffic Density is the most important of the three primary macroscopic traffic stream parameters, because it is most directly related to traffic demand(Traffic Engineering, 2004). It is defined as the number of existing vehicles within a given distance at a certain time. However, due to weather, road conditions, and cost issues, collecting density directly on the field is difficult. This makes studies of density less actively than those of traffic volume or velocity. For these reasons, there is insufficient attempts on divers collecting methods or researches on the accuracy of measured values. In this paper, we used the 'Density Measuring System' based on the synthesise technology of several camera images as a method to measure density. The collected density value by the 'Density Mesuring System' is selected as the true value based on the density define, and this value was compared with the density calculated by the traditional measurement methods. As a result of the comparison, the density value using the fundamental equation method is the closest to the true value as RMSE shows 1.8 to 2.5. In addition, we investigated some issues that can be overlooked easily such as the collecting interval to be considered on collecting density directly by calculating the moment density and the average density. Despite the actual traffic situation of the experiment site is LOS B, it is difficult to judge the real traffic situation because the moment density values per second are observed max 16.0 (veh/km) to min 2.0 (veh/km). However, the average density measured for 15 minutes at 30-second intervals was 8.3-7.9 (veh/km) and it indicates precisely LOS B.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.4
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• pp.36-48
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• 2008

Variable Message Signs(VMS) is one of the important subsystems of Intelligent Transportation Systems (ITS), which is useful for providing drivers with real-time information on traffic, roadway or weather conditions. In order to maximize the effectiveness of the VMS system, it is required to reflect drivers's preference on designing and operating the system. In this context, this study was conducted to develop strategies to deliver the messages in an efficient manner while many other previous studies focused primarily on the contents of the messages, from drivers's perspectives. Drivers's preference on message expression formats and message display orders were investigated through image analysis in the perspectives of a total of 40 subjects. With respect to message expression formats, drivers preferred Gulim or Dodum in font style, middle arrangement of the letters, pictogram combination as opposed to letters only, blank time less than 0.5 sec, appearing message in animation effect, messages in single phase, non-flashing message. In the matter of message display orders, drivers preferred to obtain link or traffic information in the lust place. Then, they desired to be informed of roadway condition and instructions or recommendations for drivers to cope with unexpected events among various messages for traffic condition.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.6
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• pp.1-14
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• 2012

Traffic management centers (TMC) collect real-time traffic data from the field and have powerful databases for analysing, recording, and archiving the data. Recent advanced sensor and communication technologies have been widely applied to intelligent transportation systems (ITS). Regarding sensors, various in-vehicle sensors, in addition to global positioning system (GPS) receiver, are capable of providing high resolution data representing vehicle maneuverings. Regarding communication technologies, advanced wireless communication technologies including vehicle-to-vehicle (V2V) and vehicle-to-vehicle infrastructure (V2I), which are generally referred to as V2X, have been widely used for traffic information and operations (references). The V2X environment considers the transportation system as a network in which each element, such as the vehicles, infrastructure, and drivers, communicates and reacts systematically to acquire information without any time and/or place restrictions. This study is motivated by needs of exploiting aforementioned cutting-edge technologies for developing smarter transportation services. The proposed system has been implemented in the field and discussed in this study. The proposed system is expected to be used effectively to support the development of various traffic information control strategies for the purpose of enhancing traffic safety on highways.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.4
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• pp.58-70
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• 2019

In the case of a pedestrian traffic accident, it has a large-scale danger directly connected by a fatal accident at the time of the accident. The domestic ITS is not used for intelligent risk classification because it is used only for collecting traffic information despite of the construction of good quality traffic infrastructure. The CNN based pedestrian detection classification model, which is a major component of the proposed system, is implemented on an embedded system assuming that it is installed and operated in a restricted environment. A new model was created by improving YOLO's artificial neural network, and the real-time detection speed result of average accuracy 86.29% and 21.1 fps was shown with 20,000 iterative learning. And we constructed a protocol interworking scenario and implementation of a system that can connect with the ITS. If a pedestrian accident prevention system connected with ITS will be implemented through this study, it will help to reduce the cost of constructing a new infrastructure and reduce the incidence of traffic accidents for pedestrians, and we can also reduce the cost for system monitoring.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.6
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• pp.203-213
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• 2021

A vehicle crash occurs due to various factors such as the geometry of the road section, traffic, and driver characteristics. A safety performance function has been used in many studies to estimate the relationship between vehicle crash and road factors statistically. And depends on the purpose of the analysis, various characteristic variables have been used. And various characteristic variables have been used in the studies depending on the purpose of analysis. The existing domestic studies generally reflect the average characteristics of the sections by quantifying the traffic volume in macro aggregate units such as the ADT, but this has a limitation that it cannot reflect the real-time changing traffic characteristics. Therefore, the need for research on effective aggregation units that can flexibly reflect the characteristics of the traffic environment arises. In this paper, we develop a safety performance function that can reflect the traffic characteristics in detail with an aggregate unit for one hour in addition to the daily model used in the previous studies. As part of the present study, we also perform a comparison and evaluation between models. The safety performance function for daily and hourly units is developed using a negative binomial regression model with the number of accidents as a dependent variable. In addition, the optimal negative binomial regression model for each of the hourly and daily models was selected, and their prediction performances were compared. The model and evaluation results presented in this paper can be used to determine the risk factors for accidents in the highway section considering the dynamic characteristics. In addition, the model and evaluation results can also be used as the basis for evaluating the availability and transferability of the hourly model.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.6
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• pp.87-96
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• 2022

The traffic vulnerable, including elderly pedestrians, have a relatively low walking speed and slow cognitive response time due to reduced physical ability. Although a smart crossing system has been developed and operated to improve problem, it is difficult to operate a signal that reflects the appropriate walking speed for each pedestrian. In this study, a neural network model and a multiple regression model-based traversing speed estimation model were developed using image information collected in an area with a high percentage of traffic vulnerability. to support the provision of optimal walking signals according to real-time traffic weakness. actual traffic data collected from the urban traffic network of Paju-si, Gyeonggi-do were used. The performance of the model was evaluated through seven selected indicators, including correlation coefficient and mean absolute error. The multiple linear regression model had a correlation coefficient of 0.652 and 0.182; the neural network model had a correlation coefficient of 0.823 and 0.105. The neural network model showed higher predictive power.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.6
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• pp.114-123
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• 2023

With the development of computer vision technology, video sensors such as CCTV are detecting incident. However, most of the current incident have been detected based on existing fixed imaging equipment. Accordingly, there has been a limit to the detection of incident in shaded areas where the image range of fixed equipment is not reached. With the recent development of edge-computing technology, real-time analysis of mobile image information has become possible. The purpose of this study is to evaluate the possibility of detecting expressway emergencies by introducing computer vision technology to dash cam. To this end, annotation data was constructed based on 4,388 dash cam still frame data collected by the Korea Expressway Corporation and analyzed using the YOLO algorithm. As a result of the analysis, the prediction accuracy of all objects was over 70%, and the precision of traffic accidents was about 85%. In addition, in the case of mAP(mean Average Precision), it was 0.769, and when looking at AP(Average Precision) for each object, traffic accidents were the highest at 0.904, and debris were the lowest at 0.629.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.23 no.1
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• pp.82-96
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• 2024

While analyzing traffic flow, speed, traffic volume, and density are important macroscopic indicators, and acceleration and spacing are the important microscopic indicators. The speed and traffic volume can be collected with the currently installed traffic information collection devices. However, acceleration and spacing data are necessary for safety and autonomous driving but cannot be collected using the current traffic information collection devices. 'You Look Only Once'(YOLO), an object recognition technique, has excellent accuracy and real-time performance and is used in various fields, including the transportation field. In this study, to measure acceleration and spacing using YOLO, we developed a model that measures acceleration and spacing through changes in vehicle speed at each interval and the differences in the travel time between vehicles by setting the measurement intervals closely. It was confirmed that the range of acceleration and spacing is different depending on the traffic characteristics of each point, and a comparative analysis was performed according to the reference distance and screen angle to secure the measurement rate. The measurement interval was 20m, and the closer the angle was to a right angle, the higher the measurement rate. These results will contribute to the analysis of safety by intersection and the domestic vehicle behavior model.