• Journal of Korean Society of Transportation
• /
• v.17 no.2
• /
• pp.83-90
• /
• 1999

A computer algorithm is presented that evaluate the performance of coordinated signal timing plans for the signalized arterials. The procedures calculating delay and stops are based on Michalopoulos's analytical model derived from shock wave theory. The delay-offset relationship predicted from the algorithm produced consistent results with the delays venerated by TRANSYT-7F. From performance test, the delays estimated using the proposed a1gorithm are shown to be sensitive to the quality of progression as well as to traffic demand, link length, and turning flow ratio from upstream signal.

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

• Proceedings of the KIEE Conference
• /
• 1999.07g
• /
• pp.2938-2940
• /
• 1999

도로 색과 대비를 이루는 계수선을 도로위에 그려놓고 영상을 이용하여 통과 차량을 계수 하는 영상기반 교통량 측정 기술을 제안하였다. 기존의 컴퓨터 영상을 이용한 차량 계수 장치들은 대부분 도로와 차량의 gray level차이를 이용하는 방식이기 때문에 도로와 차량간의 구분이 쉽지 않고 그림자와 차량의 식별도 어려우며 조명에 의해 착오를 일으키기 쉬운 문제를 안고 있었다. 제안한 계수방법은 도로 위에 도로 색과 뚜렷한 대비를 이루는 띠를 도로를 가로질러 그려 놓은 다음 이를 통과하는 차량에 의해 띠의 형상이 절단되는지의 여부를 판단하여 차량을 계수 하는 방법이다. 이를 위해서 계수선을 포함하는 영상의 창을 설치하고 수시로 에지를 추출한 후, 에지의 절단 여부를 검사한다. 이때 계수선의 색과 동일한 차량이 통과할 경우에는 계수선의 에지는 절단되어 도로방향으로 연장되게 되며 계수선의 색과 다른 차량인 경우에는 계수선의 에지가 계수선의 내부로 연장되게 된다. 계수선 상에 그림자가 있는 경우에도 도로와 계수선 간의 색상변화가 뚜렷하므로 계수선의 에지 검출에는 영향을 받지 않게 된다. 제안한 알고리즘을 실험실에 설치된 모형도로와 모형 차량들을 이용하여 실험하고 결과를 제시하였다.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.15 no.5
• /
• pp.42-53
• /
• 2016

This study aims to evaluate the performance of Hook-turn operation with various sizes of bicycle waiting zone(WZ) and to determine the optimal size of bicycle WZ under various traffic and control circumstances. An extensive simulation study was performed to examine bicycle and vehicle delay trends for given experimental design. Results showed that vehicle delay was insensitive to the size of waiting zone, but bicycle delay was reduced as the size of waiting zone increased in general. The delay performance indicated a similar trend between with RTOR and without RTOR operation, but vehicle delay slightly increased and bicycle delay slightly decreased without RTOR. Regarding to optimal waiting zone size, 6 WZ was recommended for general conditions with RTOR, but 9 WZ was recommended when bicycle left-turn volume was greater than 120 v/h. 6 WZ was recommended for general conditions without RTOR, but 12 WZ was recommended when bicycle left-turn volume was greater than 90 v/h.

• Journal of Climate Change Research
• /
• v.4 no.4
• /
• pp.359-369
• /
• 2013

In this paper, correlations between driving parameters and $CO_2$ of light-duty vehicles have been analyzed. Three test vehicles equipped with PEMS (Portable Emission Measurement System) have been driven in real-road in urban areas of Seoul. Averaged vehicle speed, RPA(Relative Positive Acceleration) and stop ratio have been selected as main driving parameters. The analysis have been conducted in interrupted and uninterrupted road types. Averaged values in various driving conditions have been calculated with distance based moving averaging window method. The multiple linear regression method have been applied to account for correlation between driving parameters and $CO_2$ emissions. This approach has shown statistically that $CO_2$ emission per distance (g/km) have tendencies to be increased as decreased averaged vehicle speed and increased RPA and stop ratio. Compared with uninterrupted traffic, interrupted traffic have shown the lower vehicle speed and the higher RPA and stop ratio. These characteristics of driving parameters in interrupted traffic should cause the higher $CO_2$ emission per distance.

• International Journal of Highway Engineering
• /
• v.12 no.4
• /
• pp.61-70
• /
• 2010

The purpose of this study is to analyze the accuracy of traffic volume forecast by comparing an estimated to real traffic volume. For this study, total 10 sections of national highways, which are planned in 1980s and 1990s, were selected and traffic analysis data for highway construction were collected. In addition, targeted 10 sections were categorized into network-related and -unrelated sections. In the analysis of inaccuracy between the estimated and real traffic, for network-related sections, appeared to have lower inaccuracy. As time goes on after traffic open, inaccuracy between the estimated and real traffic appeared to be lower. In various section lengths, the longer the section length, the higher the inaccuracy is. Using 3 years passed data after traffic open, national highway have lower inaccuracy than expressway. However, the traffic analysis according to traffic open time resulted in little change of the inaccuracy.

• Journal of Korean Society of Transportation
• /
• v.22 no.4 s.75
• /
• pp.43-56
• /
• 2004

The KHCM procedure is a micro level analysis at signalized intersections requiring a lot of input variables and complex computations. The research was to investigate the possibility of simplifying the analysis procedures by using the generalized or the combined variables that less influence on the adjusted traffic volume and through-car equivalents of left or right turns. It was also tried to make lane grouping into directional flow ratio(v/s) based on a field surveys. The maximum and minimum values of each variables were compared with each other through the KHCM analysis procedures in terms of control delay. The lane grouping and the synthetical influence of a simplified method was evaluated with the scenario built in prevailing maximum and minimum conditions. The study showed that the control delay was not significantly sensitive to the selected variables and the lane grouping and their synthetical influence as well.

• Journal of Korean Society of Transportation
• /
• v.25 no.2 s.95
• /
• pp.73-81
• /
• 2007

The purpose of this paper is to perform a basic study on the interaction between lanes, which can be achieved through analyzing traffic breakdown at the microscopic level. Using aerial photographic data for the microscopic analysis, this study analyzed the characteristics of traffic flow at a merging area. This research produced aggregated traffic data such as flows, speeds, and densities in 30 second intervals by lane for the macroscopic analysis and individual headway data by lane for the microscopic analysis. The paper contains an analysis of lane characteristics through flows, speeds, densities, and headway variations and also investigates the influence of ramp flows on mainline flows with space-time diagrams. Firstly, the merging area in this study is divided into three sections: before-merging, during-merging, and after-merging. The transition process was analyzed at each lane. Secondly, the breakdown was observed in detail with data divided in 50-foot units. The breakdown was checked through the relationships between ramp and freeway mainline flows, various techniques were proposed to analyze the breakdown, and the formation of breakdown was introduced as three stages in this study. In the near future, the findings of this study could contribute to determining the dynamic capacity on freeways by easily understanding changeable traffic breakdown patterns over time and space.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.26 no.3
• /
• pp.1-11
• /
• 2023

COVID-19 has caused the dramatic reduction of public transportation demand in Busan Metropolitan City, that is, daily public transportation trips in 2020 dropped by approximately 920,000 trips from 2019 based on the public transportation card data. This study investigated the underlying factors affecting the public transportation demand discrepancy between before and after COVID-19 at the primary administration unit(i.e., Eup, Myeon, Dong) level with Ordered Logistic Regression model. Finding of this study is as follows. The primary administration units characterized with high ratio of welfare recipients, industrial area, and day boarders were heavily dependent on public transit, indicating little change in public transportation demand. On the other hands, the primary administration units which have high ratio of urban rail transit uses experienced significant reduction of public transportation demand. In conclusion, transportation policies taken under emergent situation such as COVID-19 need to take into account the region-based characteristics rather than unilateral ones.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2005.11a
• /
• pp.51-54
• /
• 2005

최근 도로 네트워크 환경에서 날로 증가하는 교통 수요를 충족시키고 각종 교통 문제를 해결하기 위해서 지능형교통시스템(ITS, Intelligent Transportation System)을 적용하고 있다. 특히, 첨단교통정보 시스템(ATIS, Advanced Traveler Information System)은 개별 차량의 주행을 최적화시키는 시스템으로서 운전자에게 출발지에서 목적지까지 빠르고 쾌적한 주행경로를 제공하는 차량 경로계획 수립을 제공한다. 하지만 이러한 시스템은 도로 구간의 비용으로 정적인 값을 이용하므로 동적으로 변화하는 구간 비용을 가지고 도로 네트워크에서 최단 경로를 제공하기는 어렵다. 따라서, 이 논문에서는 교통 혼잡을 고려한 최단 경로 탐색 연산자를 제안한다. 제안된 연산자는 현재 시간 비용과 과거의 시간 비용 변화 량을 더하여 출발지에서 목적지까지 경로를 탐색하는데 이용한다. 이러한 방법은 시간에 따라 변화하는 도로의 상황을 반영하며 출발지에서 목적지까지의 최단 경로뿐만 아니라 예상 도착 시간을 추정할 수 있다. 또한 제안된 연산자는 효율적인 도로 이용, 물류비용 감소, 응급 상황 대체, 연료 절약 및 환경 오염 감소 등의 장점을 가지며 첨단교통정보시스템에서 응용 될 수 있다.