2011년∼2016년 고속도로 교통사고 정보 자료에 따르면 고속도로에서는 매년 9,200건 이상의 교통사고가 발생하고 있는 것으로 나타났다. 이 중 봉평터널 버스 6중 추돌사고(2016년), 둔내터널 부근 버스 추돌사고(2017년)와 같은 중차량으로 인한 대형 교통사고는 사회적으로 큰 반향을 불러일으키고 있다. 이에 본 연구에서는 고속도로 교통사고 정보 자료를 이용하여 사고등급, 사고원인, 사고유형, 사고차량수 등 다양한 측면에서 터널부 교통사고에 대한 현황 분석을 수행하였다. 고속도로 터널 연장에 따른 교통사고 현황을 분석하기 위하여 터널 연장 1km를 기준으로 1km 미만 터널, 1km 이상으로 구분하여 분석을 수행하였다. 고속도로 전체 터널 중 터널 내에서 교통사고가 발생한 터널을 구분해 보면 ‘1km 이상’터널은 160개소 ‘1km 미만’ 터널은 369개소로 나타났다. 교통사고 발생 터널의 평균연장은 고속도로 전체 터널의 평균연장에 비해서 긴 것으로 나타났다. 고속도로 터널 연장에 따른 교통사고 현황은 ‘1km 미만’ 터널의 사고 건수가 ‘1km 이상’ 터널에 비해서 많은 것으로 나타났다. 그러나 A급 교통사고 건수, 사망자 수, 부상자 수의 경우 ‘1km 이상’ 터널이 더 많은 것으로 분석되었다. 교통사고가 발생한 터널의 평균 교통사고 건수, 평균 사망자 수 평균 부상자수는 ‘1km 이상’ 터널이 ‘1km 미만’ 터널에 비해서 많았으며 교통사고 당 평균 사망자 수 및 평균 부상자 수 또한 많은 것으로 나타났다. 고속도로 노선별 터널부 교통사고 건수는 ‘순천완주선’이 총 278건으로 터널부 교통사고가 가장 많이 발생한 노선으로 나타났으며, 터널부 B급 이상 교통사고 건수의 경우 ‘중부내륙선’이 22건으로 타 노선에 비해서 심각한 교통사고의 발생 빈도가 월등히 높은 것으로 파악되었다. 고속도로 일반부와 터널부 교통사고 분석결과 일반부에 비해서 터널부의 A∼C급 사고 비율이 높은 것으로 나타났다. 사고원인 중 운전자 요인 비교결과 일반부는 ‘과속’이 가장 높은 비율을 차지한 반면에 터널부는 ‘주시태만’과 ‘졸음’이 높은 비율을 차지하는 것으로 나타났다. 사고차량 수별 교통사고 비율은 일반부의 경우 차량 ‘1대’의 단독 사고 비율이 74.1%, ‘2대’가 18.7%인 반면에 터널부는 일반부에 비해서 ‘2대’인 경우가 6.8%p 높은 것으로 나타났다. 고속도로 터널부 교통사고 중 사고원인차가 화물차, 승합차, 트레일러, 특수차량 등 중차량에 해당하는 교통사고 자료 분석결과 터널부 교통사고 중 B급 이상 사고 비율은 3.5%인 반면에 중차량 교통사고의 비율은 5.6%로 중차량으로 인한 사고의 피해 정도가 더 큰 것으로 나타났다. 사고원인의 경우 일반부 교통사고 및 터널부 일반 교통사고와 달리 터널부 중차량 교통사고의 경우 ‘차량요인’에 의한 교통사고가 ‘기타요인’에 비해서 높은 비율을 차지하는 것으로 나타났다. 사고 차량수는 터널부 일반 교통사고에 비해서 사고차량 수 ‘1대’의 비율은 3.2%p 감소한 반면 ‘2대’의 비율은 1.9%p 상승한 것으로 나타났다. 고속도로 터널부 중차량 교통사고의 연평균 치사율은 5.72%로 터널부 일반 교통사고에 비해서 2.65%p 높은 것으로 나타났으며 사고건당 부상자수 또한 연평균 0.1명 높게 나타났다

OBJECTIVES: This study aims to review a plan to reduce the shoulder width of a deformed round-trip two-lane highway with low traffic volume. METHODS: Installation of a passing lane on a round-trip two-lane (one-way one-lane) highway, and reduction of a shoulder for a round-trip four-lane highway. RESULTS : It is necessary to establish a design criterion for various highways, because the plan to reduce the lane or shoulder width of a highway with low traffic volume was analyzed to have an economic efficiency of 6.8~7.0%. CONCLUSIONS: It is necessary to seek for a plan to establish a national trunk net early by efficiently using the limited financial resources to cope with the traffic demand elastically.

PURPOSES: This study was initiated to estimate the benefits from the campaign to prevent drowsy driving crashes on expressways. The study was conducted by the Korea Expressway Corporation using a contingent valuation method. METHODS : First, a questionnaire was designed for a preliminary survey. From the survey’s results, the initial willingness to pay for the campaign was determined by averaging different amounts of payments chosen under virtual scenarios in the survey. The willingness to pay data was used to find a first bid price for the open-ended method used for the second survey. After that, a primary questionnaire was designed and conducted using a single dichotomous choice question (SDBCQ). Drivers at expressway resting areas were asked their willingness to pay for the campaign. Based on statistical analysis using data collected from the second survey, the mean willingness to pay was estimated using a probability utility function. Finally, the benefit from the campaign was calculated using the estimated willingness to pay and accident data on expressways. CONCLUSIONS : Based on the result from the contingent valuation method, the benefit from the campaign to prevent drowsy driving crashes was estimated to be 170.6 won per expressway trip. The benefit is to be paid as an additional toll. In addition, the traffic crash cost estimate is about 2,209,680,000 won less than the cost during the same period in 2014.

PURPOSES: This paper proposes a reliability index for the safety evaluation of freeway sections. It establishes a reliability index as a safety surrogate on freeways considering speeds and speed dispersions. METHODS : We collated values of design elements including radii, curve lengths, vertical slopes (absolute values), superelevations, and vertical slopes from seven freeway sections in Korea. We also collected data about driving speeds, traffic accidents, and their deviations. We established a reliability index using these variables. RESULTS : The average radii, curve lengths, and superelevations are highly correlated with the incidence of traffic accidents. Deviations in radius and curve lengths show an especially high correlation. The reliability index, derived from speed and speed dispersions of the seven freeway sections, also correlated highly with accidents with a correlation index of 0.63. CONCLUSIONS : Since the reliability index obtained from speed and speed dispersions are highly correlated with traffic accidents, we conclude that a reliability index can be a safety surrogate on freeways considering speeds and speed dispersions together in terms of design and operational levels.

PURPOSES : Low visibility caused by dark surroundings at nighttime affects the likelihood of accidents, and various efforts, such as installing road safety facilities, have been made to reduce accidents at night. Despite these efforts, the nighttime severity index (SI) in Korea was higher than the daytime SI during 2011-2014. This study determined the factors affecting daytime and nighttime accident severity through a discriminant analysis. METHODS: Discriminant analysis. RESULTS: First, drowsiness, lack of attention, and lighting facilities affected both daytime and nighttime accident severity. Accidents were found to be caused by a low ability to recognize the driving conditions and a low obstacle avoidance capability. Second, road conditions and speeding affected only the daytime accident severity. Third, failure to maintain a safe distance significantly affected daytime accident severity and nonsignificantly affected nighttime accident severity. The majority of such accidents were caused by rear-end collisions of vehicles driving in the same direction; given the low relative speed difference in such cases, the shock imparted by the accidents was minimal. CONCLUSIONS: Accidents caused by a failure to maintain a safe distance has lower severity than do accidents caused by other factors.

PURPOSES: This study analyzed the lane-by-lane traffic flow characteristics in Korea by using real-world data, including congestion levels, for 2-, 3-, and 4-lane freeways. METHODS : On the basis of a literature review, lane flow and speed characteristics were analyzed using flow measurements and speed ratios. In addition, the effect of congestion levels on traffic flow were visualized using rescaled cumulative plots. RESULTS: Driver behavior varied depending on the congestion level. During free-flow conditions, the lane-use ratio of individual lanes varied largely, whereas during congestion, the ratio was nearly the same for all lanes (i.e., equilibrium). During maximum-flow and congestion conditions, the median lane was used more than the shoulder lane, whereas during all other conditions, the shoulder lane had a higher lane-use ratio. In 3- or 4-lane freeways, the lane-use ratio of the median lane always exceeded 1 and was the highest during free-flow conditions. CONCLUSIONS : The results of the present analysis can be used as an index to predict congestion before a lane is overcapacitated. Moreover, the results can be applied in variable lane guidance systems, such as car navigation systems and variable message displays, to control traffic flow.

PURPOSES : This study aims to examine the differences between the existing traffic demand forecasting method and the traffic demand forecasting method considering future regional development plans and new road construction and expansion plans using a four-step traffic demand forecast for a more objective and sophisticated national highway maintenance. This study ultimately aims to present future pavement deterioration and budget forecasting planning based on the examination. METHODS: This study used the latest data offered by the Korea Transport Data Base (KTDB) as the basic data for demand forecast. The analysis scope was set using the Daejeon Metropolitan City’s O/D and network data. This study used a traffic demand program called TransCad, and performed a traffic assignment by vehicle type through the application of a user equilibrium-based multi-class assignment technique. This study forecasted future traffic demand by verifying whether or not a realistic traffic pattern was expressed similarly by undertaking a calibration process. This study performed a life cycle cost analysis based on traffic using the forecasted future demand or existing past pattern, or by assuming the constant traffic demand. The maintenance criteria were decided according to equivalent single axle loads (ESAL). The maintenance period in the concerned section was calculated in this study. This study also computed the maintenance costs using a construction method by applying the maintenance criteria considering the ESAL. The road user costs were calculated by using the user cost calculation logic applied to the Korean Pavement Management System, which is the existing study outcome. RESULTS : This study ascertained that the increase and decrease of traffic occurred in the concerned section according to the future development plans. Furthermore, there were differences from demand forecasting that did not consider the development plans. Realistic and accurate demand forecasting supported an optimized decision making that efficiently assigns maintenance costs, and can be used as very important basic information for maintenance decision making. CONCLUSIONS : Therefore, decision making for a more efficient and sophisticated road management than the method assuming future traffic can be expected to be the same as the existing pattern or steady traffic demand. The reflection of a reliable forecasting of the future traffic demand to life cycle cost analysis (LCCA) can be a very vital factor because many studies are generally performed without considering the future traffic demand or with an analysis through setting a scenario upon LCCA within a pavement management system.

도로 안전에는 다양한 요인들이 복합적으로 작용한다. 이러한 요인들 중 미끄럼 저항은 도로 포장면과 타이어 사이의 마찰 저항을 말하며, 도로 안전에 매우 중요한 요소이다. 비 오는 날은 시야확보가 어렵고, 미끄러운 노면 때문에 조향과 제동에 어려움을 겪게 되어 사고위험성이 높아지게 된다. 비 오는 날 교통 사고의 위험성은 교통사고 100건당 사망자수인 치사율을 보면 알 수 있는데, 교통안전정보관리시스템의 통계에 의하면 2012~2014년의 교통사고 중 맑은 기상상태에서는 치사율이 2.16%이지만 비, 눈 상태의 치사율은 각각 2.76, 2.63%로 높게 집계되었다. 또한 도로교통공단의 통계에 따르면 2009~2011년 고속 국도의 야간 치사율은 10.6명으로 도로종류 중에서 가장 높은 것으로 나타났다. 따라서 본 연구에서는 고 속도로의 노면의 상태(건조, 젖음)와 시간(심야, 첨두, 비첨두)을 고려하여 고속도로의 미끄럼 저항 관리 기준 방안 제시를 위하여 고속도로 교통사고와 미끄럼 저항간의 관계를 누적사고건수비율/누적도로연장 비율을 평가지수로 이용하여 경부고속도로와 영동고속도로를 중심으로 분석하였다. 교통사고와 미끄럼 저항간의 관계 분석을 통하여 포장종류, 노면상태, 시간에 따라 누적사고건수비율/ 누적도로연장비율이 달라지는 것을 다음과 같이 확인하였다. 경부, 영동 고속도로 모두 미끄럼 저항이 낮 을 때 평가지수가 높은 것으로 분석되었다. 또한 젖은 노면 상태에서 평가지수가 높게 나타났다. 향후 본 연구결과를 토대로 고속도로 미끄럼 저항 관리기준을 합리적으로 수립할 수 있는 방안을 마련할 계획이 며, 고속도로 안전관리에 단계별 관리기준을 제공하는데 기여할 수 있을 것으로 판단된다.

본 연구는 지능형 교통시스템(ITS)이 도로교통안전에 미치는 영향을 분석하고 국내외 ITS 기술동향을 설명하였으며, 향후 도로교통안전을 위한 ITS 산업이 나아가야 할 정책적 방향을 제안하였습니다. 교통안 전을 위한 ITS 발전 전략은 크게 다섯 가지 정도로 제언되었습니다. 첫 번째, ITS 기반시설에 대한 정부의 연구개발 지원이 규모/범위의 경제효과를 고려한 선택&집중이 필요하며, 두 번째, 교통안전 증진을 위해 서 고속도로 이외에 ITS 인프라의 지속적인 구축이 필요하다는 것이 강조 되었습니다. 세 번째, 도로-차 량이 양방향으로 연결된 V2X 기술의 선진국 수준의 연구개발 증가 및 상용화 필요가 강조되었으며, 네 번 째, ITS 인프라 구축 투자와 동시에 운전자의 직접적인 안전과 연계된 교통안전관리증가를 위한 선제적 기 술개발이 필요함이 제기되었습니다. 마지막으로, 급격한 인구구조가 야기하는 고령화 사회에 대비하여 고 령운전자를 배려한 미래지향적 고령자 교통시스템의 기술개발이 시급한 시점으로 제안되었습니다.

본 연구에서는 선진 4개국(미국, 영국, 독일, 일본)의 도로교통스톡 수준을 분석하였습니다. 한국과 각 국가별 도로 연장 수준을 비교하기 위해 2005년과 2013년 국토계수당 도로연장*을 산정하였습니다. 2005년 국토계수당 도로 연장을 살펴보면, 미국·독일·영국은 3.0 이상을 상회하며, 4개국 국제평균 (4.12)대비 높은 수치를 보였으며, 일본은 5.7으로 상대적으로 매우 높은 수준이 확인되었습니다. 반면 한국은 1.47로 4개국 평균의 절반수준에도 훨씬 못 미치는 것으로 나타났습니다. 한편, 2005년도와 비교 하여 미국의 2013년 국도계수당 도로 연장은 감소하였으며, 독일･영국･일본은 다소 증가하였습니다. 한 국(1.48)은 소폭 증가하였으나 2013년에도 여전히 4개국 평균(4.15)보다 훨씬 낮은 수준을 보여주고 있습 니다. 자동차 등록 대수 부문에서는 2005년과 2013년에 미국이 가장 높은 수치를 보이고 있으며, 이례적 으로 일본이 2005년에 비해 2013년의 자동차 등록수가 감소하였습니다. 도로화물운송 부문에서는 2005년과 2013년을 비교했을 때 미국과 한국은 도로화물운송이 점차 증가하 였으나, 독일･영국･일본은 도로화물운송이 감소하였습니다. 도로여객수송 부문은 2005년과 2013년 모두 미국이 상대적으로 높은 수준이었으며, 이어 독일이 높은 수치를 보였습니다. 이례적으로 일본이 2005년 에는 1km당 933,005 백만 인을 수송하다가 2013년에는 76,000 백만인-km로 현저히 낮아졌는데, 이는 2010년 이후 계속 유지되고 있는 추세로 보입니다. 한국은 2005년과 비교하여 2013년에 도로여객수송이 증가하였지만, 여전히 선진국 평균에 비교해서는 낮은 수치를 보이고 있습니다. 도로부문의 에너지소비량 은 2005년 대비 2013년 한국을 제외한 4개국에서 점차 에너지 소비량이 감소하고 있는 추세를 보이며, 도로부문의 인프라 투자의 경우 일본을 제외한 미국･독일･영국･한국은 2005년 대비 2013년 투자를 확대 하였습니다.

PURPOSES: The purpose of this study is to develop a methodology for estimating additional carbon emissions due to freeway incidents. METHODS : As our country grows, our highway policy has mainly neglected the environmental and social sectors. However, with the formation of a national green growth keynote and an increase in the number of people interested in environmental and social issues, problems related to social issues, such as traffic accidents and congestion, and environmental issues, such as the impact of air pollution caused by exhaust gases that are emitted from highway vehicles, are beginning to be discussed. Accordingly, studies have been conducted on a variety of environmental aspects in the field of road transport, and for the quantitative calculation of greenhouse gas emissions, using various methods. However, in order to observe the effects of carbon emissions, microscopic simulations must use many difficult variables such as cost, analysis time, and ease of analysis process. In this study, additional greenhouse gas emissions that occur because of highway traffic accidents were classified by type (incident handling time, number of lanes blocked, freeway level of service), and the annual additional emissions based on incidents were calculated. According to the results, congestion length and emissions tend to increase with an increase in incident clearance time, number of occupied lanes, and worsening level of service. Using this data, we analyzed accident data on the Gyeong-bu Expressway (Yang-Jae IC - Osan IC) for a year. RESULTS : Additional greenhouse gas emissions that occur because of highway traffic accidents were classified by type (incident handling time, number of lanes blocked, freeway level of service) and annual additional emissions caused by accidents were calculated. CONCLUSIONS: In this study, a methodology for estimating carbon emissions due to freeway incidents was developed that incorporates macroscopic flow models. The results of the study are organized in the form of a look-Up table that calculates carbon emissions rather easily.

PURPOSES: This study was initiated to estimate expressway traffic congestion costs by using Vehicle Detection System (VDS) data. METHODS : The overall methodology for estimating expressway traffic congestion costs is based on the methodology used in a study conducted by a study team from the Korea Transport Institute (KOTI). However, this study uses VDS data, including conzone speeds and volumes, instead of the volume delay function for estimating travel times. RESULTS : The expressway traffic congestion costs estimated in this study are generally lower than those observed in KOTI's method. The expressway lines that ranked highest for traffic congestion costs are the Seoul Ring Expressway, Gyeongbu Expressway, and the Youngdong Expressway. Those lines account for 64.54% of the entire expressway traffic congestion costs. In addition, this study estimates the daily traffic congestion costs. The traffic congestion cost on Saturdays is the highest. CONCLUSIONS : This study can be thought of as a new trial to estimate expressway traffic congestion costs by using actual traffic data collected from an entire expressway system in order to overcome the limitations of associated studies. In the future, the methodology for estimating traffic congestion cost is expected to be improved by utilizing associated big-data gathered from other ITS facilities and car navigation systems.

PURPOSES: The objective of this study is to analyze factors affecting traffic accident severity for determining countermeasures on freeway climbing lanes. METHODS : In this study, an ordered probit model, which is a widely used discrete choice model for categorizing crash severity, was employed. RESULTS: Results suggest that factors affecting traffic accident severity on climbing lanes include speed, drowsy driving, grade of uphill 3%, gender (male offender and male victim), and cloud weather. CONCLUSIONS : Several countermeasures are proposed for improving traffic safety on freeway climbing lanes based on the analysis of crash severity. More extensive analysis with a larger data set and various modeling techniques are required for generalizing the results.

PURPOSES: The purpose of this thesis is to evaluate the effectiveness of an active noise cancellation (ANC) system in reducing the traffic noise level against frequencies from the predictive model developed by previous research. The predictive model is based on ISO 9613-2 standards using the Noble close proximity (NCPX) method and the pass-by method. This means that the use of these standards is a powerful tool for analyzing the traffic noise level because of the strengths of these methods. Traffic noise analysis was performed based on digital signal processing (DSP) for detecting traffic noise with the pass-by method at the test site. METHODS : There are several analysis methods, which are generally divided into three different types, available to evaluate traffic noise predictive models. The first method uses the classification standard of 12 vehicle types. The second method is based on a standard of four vehicle types. The third method is founded on 5 types of vehicles, which are different from the types used by the second method. This means that the second method not only consolidates 12 vehicle types into only four types, but also that the results of the noise analysis of the total traffic volume are reflected in a comparison analysis of the three types of methods. The constant percent bandwidth (CPB) analysis was used to identify the properties of different frequencies in the frequency analysis. A-weighting was applied to the DSP and to the transformation process from analog to digital signal. The root mean squared error (RMSE) was applied to compare and evaluate the predictive model results of the three analysis methods. RESULTS: The result derived from the third method, based on the classification standard of 5 vehicle types, shows the smallest values of RMSE and max and min error. However, it does not have the reduction properties of a predictive model. To evaluate the predictive model of an ANC system, a reduction analysis of the total sound pressure level (TSPL), dB(A), was conducted. As a result, the analysis based on the third method has the smallest value of RMSE and max error. The effect of traffic noise reduction was the greatest value of the types of analysis in this research. CONCLUSIONS : From the results of the error analysis, the application method for categorizing vehicle types related to the 12-vehicle classification based on previous research is appropriate to the ANC system. However, the performance of a predictive model on an ANC system is up to a value of traffic noise reduction. By the same token, the most appropriate method that influences the maximum reduction effect is found in the third method of traffic analysis. This method has a value of traffic noise reduction of 31.28 dB(A). In conclusion, research for detecting the friction noise between a tire and the road surface for the 12 vehicle types needs to be conducted to authentically demonstrate an ANC system in the Republic of Korea.

PURPOSES: The purpose of this study is to estimate the impact of variable message signage (VMS) on traffic safety as a function of road curve radius using statistical methods. METHODS: In order to analyze the impact of VMS installations on traffic safety, travel speed, lateral distance, and geometric data relating to road curvature in each study area was acquired and analyzed for the impact of providing VMS information on driver performance and traffic safety using statistical methods including student t-test, Mann-Whitney test, and the Anderson-Darling test for estimating traffic safety hazard zone in each lane. RESULTS: As a result of analyzing driver performance characteristics before and after providing VMS information, it was determined that by providing VMS information, mean travel speed is deceased and vehicles are driven with increased precision, following the centerline in the first and second lanes. Also the results of analyzing traffic safety impacts of VMS indicate that traffic safety performance factors in the first lane of the Gapyeong section can, on average, increase in the left and right side of the lane by 19.22% and 68.98%, respectively, and in the case of the second lane, safety impacts, on average, can increase in both sides by 100%. For the Hongcheon section, traffic safety impacts in the first lane, on average, can increase along the left and right sides of the lane by 32.31% and 47.18%, and within the second lane, traffic safety can be increased along the left and right side of the lane by 10.97% and -0.01%, respectively. CONCLUSIONS: Based on the results of this study, the impact on traffic safety obtained by providing VMS information for road sections with smaller curve radii is greater than can be obtained for road sections with larger curve radii.