• Title/Summary/Keyword: traffic accident estimation

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Intensity estimation with log-linear Poisson model on linear networks

  • Idris Demirsoy;Fred W. Hufferb
    • Communications for Statistical Applications and Methods
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    • v.30 no.1
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    • pp.95-107
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    • 2023
  • Purpose: The statistical analysis of point processes on linear networks is a recent area of research that studies processes of events happening randomly in space (or space-time) but with locations limited to reside on a linear network. For example, traffic accidents happen at random places that are limited to lying on a network of streets. This paper applies techniques developed for point processes on linear networks and the tools available in the R-package spatstat to estimate the intensity of traffic accidents in Leon County, Florida. Methods: The intensity of accidents on the linear network of streets is estimated using log-linear Poisson models which incorporate cubic basis spline (B-spline) terms which are functions of the x and y coordinates. The splines used equally-spaced knots. Ten different models are fit to the data using a variety of covariates. The models are compared with each other using an analysis of deviance for nested models. Results: We found all covariates contributed significantly to the model. AIC and BIC were used to select 9 as the number of knots. Additionally, covariates have different effects such as increasing the speed limit would decrease traffic accident intensity by 0.9794 but increasing the number of lanes would result in an increase in the intensity of traffic accidents by 1.086. Conclusion: Our analysis shows that if other conditions are held fixed, the number of accidents actually decreases on roads with higher speed limits. The software we currently use allows our models to contain only spatial covariates and does not permit the use of temporal or space-time covariates. We would like to extend our models to include such covariates which would allow us to include weather conditions or the presence of special events (football games or concerts) as covariates.

A Study on the Road Safety Analysis Model: Focused on National Highway Areas in Cheonbuk Province (도로 안전성 분석 모형에 관한 연구: 전라북도 국도 권역을 중심으로)

  • Lim, Joonbeom;Kim, Joon-Ki;Lee, Soobeom;Kim, Hyunjin
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.34 no.2
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    • pp.583-595
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    • 2014
  • Currently, Korean transportation policies are aiming for increase of safety and environment-friendly and efficient operation, by avoiding construction and expansion of roads, and upgrading road alignments and facilities. This is revealed by that there have been 22 road expansion projects (30%) and 50 road improvement projects (70%) under the 3rd Five-Year Plan for National Highways ('11~'15), while there were 53 road expansion projects (71%) and 22 road improvement projects (29%) under the 2nd Five-Year Plan for National Highways. For more effective road improvement projects, there is a need of choosing projects after an objective and scientific safety assessment of each road, and assessing safety improvement depending on projects. This study is intended to develop a model for this road safety analysis and assessment. The major objective of this study is creating a road safety analysis and assessment model appropriate for Korean society, based on the HSM (Highway Safety Manual) of the U.S. In order to build up data for model development, the sections thought to have identical geometrical structure factors in 5 lines, Cheonbuk province, were divided as homogeneous sections, and representative values of geometric structures, facilities, traffic volume, climate conditions and land usage were collected from the 1,452 sections divided. In order to build up data for model development, the sections thought to have identical geometrical structure factors in 5 lines, Cheonbuk province, were divided as homogeneous sections, and representative values of geometric structures, facilities, traffic volume, climate conditions and land usage were collected from the 1,452 sections divided. The collected data was processed correlation analysis of each road element was implemented to see which factor had a big effect on traffic accidents. On the basis of these results, then, an accident model was established as a negative binomial regression model.Using the developed model, an Crash Modification Factor (CMF) which determines accident frequency changes depending on safety performance function (SPF) predicting the number of accident occurrence through traffic volume and road section expansion, road geometric structure and traffic properties, was extracted.

Analysis of Uncertainties in Estimation of Critical Speeds from Tire Yaw Marks (타이어 요마크로부터 임계속도 추정의 불확실성 해석)

  • Han, Inhwan
    • Transactions of the Korean Society of Automotive Engineers
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    • v.23 no.4
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    • pp.361-370
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    • 2015
  • There will inevitably be errors and uncertainties in tire yaw mark related critical speed formula, which is derived merely from the relationship between the centrifugal force and the friction force acting on the point-mass vehicle. Constructing and measuring yaw marks through appropriate simulation works have made it possible to perform uncertainty analysis in calculation of critical speeds under variation of variety of conditions and parameters while existing yaw mark experimental tests have not performed properly. This paper does not present only the critical speed analysis results for parametric sensitivity and uncertainty of chord and middle ordinate, coefficient of friction and road grade, but also modeling uncertainty such as variation of braking level during turning and vehicle size. The yaw mark analysis methods and results may be now applied in practice of traffic accident investigation.

A Study on Estimation of Human Life Cost Occurred by Traffic Accident (교통사고 인명피해비용 원단위 추정에 관한 연구)

  • 홍창의
    • Journal of Korean Society of Transportation
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    • v.15 no.1
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    • pp.27-43
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    • 1997
  • 본 연구의 목적은 1995년 우리 나라에서 발생한 교통사고의 인명피해비용을 추정 하는 것이다. 인명피해비용추정을 위한 방법론으로는 인적 자본법을 사용하였다. 인적자본 법의 기본이 되는 미래손실생산량의 계산은 임금을 기본으로 하지 않고 GNP를 기준으로 삼는다. GNP 상승률을 8.14%로 고정하고, 성장률에 대한 할인율의 비를 0.92, 0.94, 0.98 로 정하고, 이에 따른 할인율은 0.17, 0.15, 0.10으로 계산된다. 따라서, 각각의 비율에 따 른 총 인명피해액은 1조 2천억원, 1조 5천억원, 2조 6천억원이 된다. 또한, 평균인명피해액 을 구하면, 1억 2천 5백만원, 1억 5천 3백만원, 2억 5천 5백만원이 되며, 비용-편익 분석 을 위한 추정된 총 주행거리당 원단위 비용은 각각의 경우, 5원, 6원, 10원으로 산정 되었 다. 본고에서 추정한 총 주행거리당 원단위 비용은 도로 안전시설물 투자전 평가에 도움을 줄 수 있으리라 기대된다.

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Bayesian Collision Risk Estimation Algorithm for Efficient Collision Avoidance against Multiple Traffic Vessels (다중 선박에서 효율적인 충돌 회피를 위한 베이지안 충돌 위험도 추정 알고리즘)

  • Song, Byoung-Ho;Lee, Keong-Hyo;Jeong, Min-A;Lee, Sung-Ro
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.36 no.3B
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    • pp.248-253
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    • 2011
  • Collision avoidance algorithm of vessels have been studied to avoid collision and grounding of a vessel due to human error. In this paper, We propose a collision avoidance algorithm using bayesian estimation theory for safety sailing and reduced risk of collision accident. We calculate collision risk for efficient collision avoidance using bayesian algorithm and determined the safest and most effective collision risk is predicted by using re-planned with re-evaluated collision risk in the future(t=t'). Others ship position is assumed to be informed from AIS. Experimental results show that we estimate the safest and most effective collision risk.

A Study on the Public Evacuation Time Estimates for Radiological Emergency Plan and Preparedness of Wolsong Nuclear Power Plant Site (방사선 비상계획을 위한 월성원전 주변 주민 소개시간 예측 연구)

  • Lee, Gab-Bock;Bang, Sun-Young;Chung, Yang-Geun
    • Journal of Radiation Protection and Research
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    • v.32 no.2
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    • pp.79-88
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    • 2007
  • When an accident occurs at nuclear power plant and radionuclide material is released to the area around the plant, public evacuation is considered as a measure to protect the safety of the residents nearby. This study draws factors required to estimate evacuation time and make estimation of the time to evacuate all residents from the EPZ of Wolsong site in consideration of traffic condition in the neighborhood and on the basis of field data around the site for each factor. The traffic capacity and the traffic volume by season were investigated for the traffic analysis and simulation within EPZ of Wolsong site. As a result, the background traffic volume by season were established. To estimate TGT(Trip Generation Time), the questionnaire surveys were carried out for resident and transient. The TSIS code was applied to traffic analysis in the events of daytime/night and normal/adverse weather under normal day/summer peak traffic condition. The results showed that the evacuation time required for total vehicles to move out from EPZ took generally from 118 to 150 minutes. The evacuation time took longer maximum 17 minutes at night than daytime during summer peak traffic.

Intelligent Optimal Route Planning Based on Context Awareness (상황인식 기반 지능형 최적 경로계획)

  • Lee, Hyun-Jung;Chang, Yong-Sik
    • Asia pacific journal of information systems
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    • v.19 no.2
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    • pp.117-137
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    • 2009
  • Recently, intelligent traffic information systems have enabled people to forecast traffic conditions before hitting the road. These convenient systems operate on the basis of data reflecting current road and traffic conditions as well as distance-based data between locations. Thanks to the rapid development of ubiquitous computing, tremendous context data have become readily available making vehicle route planning easier than ever. Previous research in relation to optimization of vehicle route planning merely focused on finding the optimal distance between locations. Contexts reflecting the road and traffic conditions were then not seriously treated as a way to resolve the optimal routing problems based on distance-based route planning, because this kind of information does not have much significant impact on traffic routing until a a complex traffic situation arises. Further, it was also not easy to take into full account the traffic contexts for resolving optimal routing problems because predicting the dynamic traffic situations was regarded a daunting task. However, with rapid increase in traffic complexity the importance of developing contexts reflecting data related to moving costs has emerged. Hence, this research proposes a framework designed to resolve an optimal route planning problem by taking full account of additional moving cost such as road traffic cost and weather cost, among others. Recent technological development particularly in the ubiquitous computing environment has facilitated the collection of such data. This framework is based on the contexts of time, traffic, and environment, which addresses the following issues. First, we clarify and classify the diverse contexts that affect a vehicle's velocity and estimates the optimization of moving cost based on dynamic programming that accounts for the context cost according to the variance of contexts. Second, the velocity reduction rate is applied to find the optimal route (shortest path) using the context data on the current traffic condition. The velocity reduction rate infers to the degree of possible velocity including moving vehicles' considerable road and traffic contexts, indicating the statistical or experimental data. Knowledge generated in this papercan be referenced by several organizations which deal with road and traffic data. Third, in experimentation, we evaluate the effectiveness of the proposed context-based optimal route (shortest path) between locations by comparing it to the previously used distance-based shortest path. A vehicles' optimal route might change due to its diverse velocity caused by unexpected but potential dynamic situations depending on the road condition. This study includes such context variables as 'road congestion', 'work', 'accident', and 'weather' which can alter the traffic condition. The contexts can affect moving vehicle's velocity on the road. Since these context variables except for 'weather' are related to road conditions, relevant data were provided by the Korea Expressway Corporation. The 'weather'-related data were attained from the Korea Meteorological Administration. The aware contexts are classified contexts causing reduction of vehicles' velocity which determines the velocity reduction rate. To find the optimal route (shortest path), we introduced the velocity reduction rate in the context for calculating a vehicle's velocity reflecting composite contexts when one event synchronizes with another. We then proposed a context-based optimal route (shortest path) algorithm based on the dynamic programming. The algorithm is composed of three steps. In the first initialization step, departure and destination locations are given, and the path step is initialized as 0. In the second step, moving costs including composite contexts into account between locations on path are estimated using the velocity reduction rate by context as increasing path steps. In the third step, the optimal route (shortest path) is retrieved through back-tracking. In the provided research model, we designed a framework to account for context awareness, moving cost estimation (taking both composite and single contexts into account), and optimal route (shortest path) algorithm (based on dynamic programming). Through illustrative experimentation using the Wilcoxon signed rank test, we proved that context-based route planning is much more effective than distance-based route planning., In addition, we found that the optimal solution (shortest paths) through the distance-based route planning might not be optimized in real situation because road condition is very dynamic and unpredictable while affecting most vehicles' moving costs. For further study, while more information is needed for a more accurate estimation of moving vehicles' costs, this study still stands viable in the applications to reduce moving costs by effective route planning. For instance, it could be applied to deliverers' decision making to enhance their decision satisfaction when they meet unpredictable dynamic situations in moving vehicles on the road. Overall, we conclude that taking into account the contexts as a part of costs is a meaningful and sensible approach to in resolving the optimal route problem.

Safety Impacts of Red Light Enforcement on Signalized Intersections (교차로 신호위반 단속카메라 설치가 차량사고에 미치는 영향)

  • Lee, Sang Hyuk;Lee, Yong Doo;Do, Myung Sik
    • Journal of Korean Society of Transportation
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    • v.30 no.6
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    • pp.93-102
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    • 2012
  • The frequency and severity of traffic accidents related to signalized intersections in urban areas have been more serious than those in both arterial segments and crosswalks. Especially, traffic accidents involved with injuries and fatalities have caused by traffic signal violations within intersections. Therefore, many countries including Korea have installed the red light enforcement camera (RLE) to reduce traffic accidents associated with the traffic signal violation. Meanwhile, many methodologies have been studied in terms of safety impacts estimation of red light enforcement, which, however, cannot be easy to conduct. In this study, safety impacts was estimated for intersections of Chicago downtown area using SPF models and EB approach. As a result, for all crash types and target traffic accident types such as "angle", "rear end", "sideswipe in the same and other directions", "turn", and "head on", fatal crashes were reduced by 26% and 38%. However, RLE may increase property-demage-only-crashes by 3.23% and 1.16%, respectively.

Relationship Between Accidents and Non-Homogeneous Geometrics: Main Line Sections on Interstates (기하구조의 비동질성을 고려한 교통사고와의 관계: 고속도로 본선구간을 중심으로)

  • Park, Min Ho;Noh, Kwan Sub;Kim, Jongmin
    • Journal of Korean Society of Transportation
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    • v.32 no.2
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    • pp.170-178
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    • 2014
  • Until now, several research on the relationship of traffic crash occurrences and geometric had been conducted and revealed that projects of road alignment, geometric improvement and hazardous segment selection reduced the number of accidents and accident severities. However, such variables did not consider the non-homogeneous characteristics of roadway segments due to the difficulty of data collection, which results in under-estimation of the standard error affecting the overall modeling goodness-of-fit. This study highlights the importance of non-homogeneity by looking at the effect of the non-homogeneous geometric variables through the modeling process. The model delivers meaningful results when using some geometric variables without relevant geometrics' variables.

Simultaneous Equation Models for Evaluating Roundabout Accidents According to Different Driving Types (연립방정식을 이용한 운전유형별 회전교차로 사고모형)

  • Kim, Kyung Hwan;Park, Byung Ho
    • Journal of Korean Society of Transportation
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    • v.30 no.5
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    • pp.3-10
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    • 2012
  • This study dealt with traffic accidents occurring within roundabouts. The objective was to develop roundabout accident models for different driving types by using simultaneous equations. In pursuing the above, this study used a statistical program SPSS 17.0 to accommodate data from 148 accidents occurred within 39 roundabouts of Korea. In addition, the 2SLS(2 stage least square) estimation method was adopted to calibrate the models. The main results are as follows. First, both the number of accidents and the EPDO were evaluated to have bilateral relationships. Second, all 6 different simultaneous equation models according to driving types were found to be statistically significant. Third, the developed models were compared to each other with respect to either common or specific variables. Finally, variables such as ADT, conflicting rate, heavy vehicle ratio, circulatory roadway width, number of circulatory roadway lane, approach lane width, average approach lanes, parking places, and bus stops were selected as independent variables for the models.