• Journal of Broadcast Engineering
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• v.22 no.4
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• pp.448-461
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• 2017

This paper proposes a vehicle counting and speed estimation method for traffic situation analysis in road CCTV videos. The proposed method removes a distortion in the images using Inverse perspective Mapping, and obtains specific region for vehicle counting and speed estimation using lane detection algorithm. Then, we can obtain vehicle counting and speed estimation results from using optical flow at specific region. The proposed method achieves stable accuracy of 88.94% from several CCTV images by regional groups and it totally applied at 106,993 frames, about 3 hours video.

• Journal of Korean Society of Transportation
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• v.30 no.5
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• pp.71-82
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• 2012

Some previous studies adopted a method statistically based on the observed traffic volumes and travel times to estimate the parameters. Others tried to find an optimal set of parameters to minimize the gap between the observed and estimated traffic volumes using, for instance, a combined optimization model with a traffic assignment model. The latter is frequently used in a large-scale network that has a capability to find a set of optimal parameter values, but its appropriateness has never been demonstrated. Thus, we developed a methodology to estimate a set of parameter values of BPR(Bureau of Public Road) function using Harmony Search (HS) method. HS was developed in early 2000, and is a global search method proven to be superior to other global search methods (e.g. Genetic Algorithm or Tabu search). However, it has rarely been adopted in transportation research arena yet. The HS based transportation network calibration algorithm developed in this study is tested using a grid network, and its outcomes are compared to those from incremental method (Incre) and Golden Section (GS) method. It is found that the HS algorithm outperforms Incre and GS for copying the given observed link traffic counts, and it is also pointed out that the popular optimal network calibration techniques based on an objective function of traffic volume replication are lacking the capability to find appropriate free flow travel speed and ${\alpha}$ value.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.5
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• pp.631-638
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• 2023

This paper is to introduce methodologies of travel time reliability evaluation using daily traffic volumes. The methodologies include desirable speed concept, the relation between averaged daily speeds and daily traffic volumes, the standardized way in integration of travel time deviations obtained from continuous highway sections. The study began with traffic data collection from a freeway line with long lasting congestion. And then, provided establishment of the relation between averaged daily speeds and daily traffic volumes, and usability of Point estimate method (PEM) to integrate travel time deviations of sections. Based on the relation between averaged daily speeds and daily traffic volumes, it is identified that travel time reliability begins to decrease around LOS (Level of Service) C even before LOS D or F. It may be concluded that travel time reliability could be evaluated based on daily traffic volumes in highway sections using standardized PEM. The methodologies introduced in the paper, could be useful in practicing evaluation of travel time reliability during the works of highway operation or highway planning.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.6
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• pp.1851-1861
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• 2014

This study aims to calculate reliable sectional travel speeds with the consideration of the characteristics of the probe data collected in the interrupted traffic flow. First, in order to analysis the characteristics of the probe data, we looked into the distribution of the sectional travel times of each probe vehicle and compared the difference in the sectional travel speeds of each probe vehicle collected by DSRC. As a result, it is shown that outliers should be removed for the distribution of the sectional travel times. However, The comparison results show that the sectional travel speeds from the DSRC probe vehicles are not significantly different. Finally, based on the distribution characteristics of the sectional travel speeds of each probe vehicle and the representative values counted during a collection period, we drew the optimal outlier removal procedure and evaluated the estimation errors. The evaluation results showed that the DSRC sectional travel speeds were found to be similar to the observed values from actually running vehicles. On the contrary, in the case of the sectional travel speeds of intra-city bus, it was analyzed that they were less accurate than the DSRC sectional travel speeds. In the future, it will be necessary to improve BIS process and make use of the travel information on intra-city buses collected in real time to find various ways of applying it as traffic information.

• Journal of Korean Society of Transportation
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• v.24 no.2 s.88
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• pp.31-41
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• 2006

The main purpose of this paper is to develop the practical method to estimate the congestion price in odor to overcome the difficulty of traditional microeconomics approach for demand and cost function concepts. In this paper, we estimate the theoretical congestion toll which reflecting the real traffic conditions such as a speed-density functions using a traffic engineering methods We calculates the optimal congestion toll based on the real traffic conditions assuming that the electronic road pricing (ERP) systems ave installed for the study road. After evaluating the various speed-density relationship methods. we found that the Drake model is best suited for the Gangbyeon Expressway Using the Drake model, the optimal congestion toll will be 94 to 3,255 Won for the traffic speed between 44km/h to 68 km/h based on wage rate method and 107 to 6,381 Won for the marginal substitution method for the Gangbyeon Expressway in city of Seoul, Korea.

• International Journal of Highway Engineering
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• v.10 no.1
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• pp.145-154
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• 2008

The purpose of this study is to evaluate the quality of on-line departure time-based link travel time estimates. For this, accuracy (i.e. estimation error) and timeliness (i.e. degree of time lag) are proposed as MOE of the quality of on-line link travel time estimates. Then the relationship between quality of link travel time estimates and link length and level of congestion is analyzed. It was found that there is trade-off between the accuracy and timeliness of link travel time estimates. The estimation error was modeled to consist of two components: one is systematic error and the other is mean square error which reflects level of congestion. further, time lag was again segmented into three parts for the analysis purpose. There are minimum one, congestion-related one, and update interval-related one. From the real-world data using AVI system, it was revealed that regardless of the link length and level of congestion, 10 minutes of time lag occurs in general.

• Journal of Korean Society of Transportation
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• v.26 no.6
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• pp.113-122
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• 2008

This study extended Park et al.(2007c), which analyzed the efficiency of a hierarchical transit network, showed the result of a real data, and analyzed its applicability. Operating cost was estimated using a model which was established in this study, and minimum transit demand was derived from the operating cost. The minimum transit demand value is just a sample calculation, thus it varies by many inside and outside factors of the model. Looking at the inside of the model, operating cost and travel speed are major factors, and the possibility of introducing urban subway becomes high when the operating cost of the transit system is low and its travel speed is high. As far as the outside factors are concerned, according to the analysis on the network structure, transit demand, and transit mode share, the minimum transit demand value which was derived in this study will be the maximum value among the possible values. In the feasibility study, the benefit is likely to be overestimated and the cost is likely to be underestimated than those of this study. It could be concluded that the methodology of a feasibility study is appropriate in the field standard. This study analyzed the efficiency of introduction of urban subway using analytical approach, thus has many shortcomings and limitations. However the practical approach, like feasibility study, has some limitations as well. This study could be a basis on establishing an analysis framework that is more accurate and reasonable by comparing analytical approach and practical approach.

• Journal of the Economic Geographical Society of Korea
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• v.21 no.2
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• pp.107-118
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• 2018

Due to the rapid economic development, traffic congestion has become a dire concern in Beijing, China. Levying a congestion toll is seen as the most effective solution to the problem. Building a congestion pricing model is a crucial step in implementing a workable toll scheme. Unlike previous attempts, this study not only covers the theoretical discussion but also considers three practical issues: the speed-density relationship, the value of travel time savings, and the determination of optimal traffic volume. We estimate the speed-density relationship by regression models and the value of travel time saved through survey results. We further suggest a way through which the government could identify the optimal traffic flow by a series of trial-and-errors, without the knowledge of exact road demand structure. Finally, a practical tolling scheme is proposed for Beijing's second ring road along with some policy recommendations.

• Journal of Environmental Policy
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• v.11 no.3
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• pp.49-65
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• 2012

Road traffic noise is closely related to road traffic environment, including traffic volumes by type and travel speed. In this study, we stated some issues and analyzed the relationships between road traffic noise and traffic flow characteristics. First, in attempt to find the answer to the question "When does the loudest traffic noise occur?" we reviewed the issue in the terms of traffic flow. As a result of analyzing level of service through Korea Highway Traffic Noise model, the actual maximum noise occurred in level of service D rather than level of service E, on the capacity state. It shows that maximum noise would be most likely to occur right before and after the peak hours. Second, this paper was looking for the method of a more easy and accurate traffic speed estimation to predict traffic noise. This paper proposed sketch planning techniques of speed-volume curve by level of service on Korea Highway Capacity Manual. As a result of trend line modeling, it was judged that quadratic form is a suitable function, and coefficient of determination ($R^2$) was higher than 0.96, respectively.

• Journal of Korean Society of Transportation
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• v.16 no.2
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• pp.117-131
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• 1998

지체함수는 교통량과 속도의 관계를 단조 증가함수로 단순화하여 교통수요예측의 교통배정모형에 사용되게 된다. 이 지체함수를 구하는 방법은 두가지로 구분할 수 있는데, 첫째는 교통배정을 통해 구해지는 추정 링크통행량과 실측 교통량을 비교해 가면서 정산하는 방법이고 둘째는 교통량-속도 관계로부터 직접 구하는 방법이다. 첫째 방법은 구해진 O/D 통행량표의 부정확성과 모형에 내재하는 오류가 이 지체함수에 포함될 가능성이 매우 높은 단점을 가지고 있다. 본 연구에서는 교통량-속도 관계로부터 직접 도로유형별 지체함수를 구하여 교통배정에 적용하는 새로운 방법을 정입하였다. 교통망 전체에 대하여 단일 지체함수를 적용하는 기존의 방법은, 교통량 변화에 따른 통행시 간의 변화가 보다 둔감한 고급도로에 변화는 고급도로일수록 둔감하게 나타나며, 교통배정에 도로유형별 지체함수를 적용할 경우 단일 지체함수 적용시에 비하여 고급도로에 더 많은 교통량이 배정되게 된다. 본 연구의 결과, 교통망상에서 보다 현실적인 도로유형별 분담을 이룰 수 있는 방안이 정립됨으로써, 지금까지 교통배정에 있어 상대적으로 과소평가되어 왔던 고속도? 등 고급도로의 실제 타당성을 반영할 수 있게 되어 도로의 기능적 배차구조가 확립된 효율적인 교통망을 구성할 수 있는 계기를 마련한 것으로 판단된다.