PURPOSES : This study estimates the effects of traffic safety policies (e.g., the Minsik Act) on the seriousness of traffic accidents in children protection zones. METHODS : A difference-in-differences framework in which the change in the gap of seriousness of traffic accidents occurring in children protection zones and those occurring outside the zone before and after the implementation of the Minsik Act was applied. Furthermore, a placebo test, in which the samples are restricted to a specific period, is irrelevant to the time of students going to school. RESULTS : On average, when the factors causing traffic accidents are not controlled, the degree of damage in traffic accidents in children protection zones appears to be more serious The introduction of the Minsik Act has been shown to reduce the damage from traffic accidents in children protection zones. In particular, illegal U-turns and signal violations increased the severity of traffic accidents in children protection zones, and trucks caused the greatest damage. CONCLUSIONS : The traffic safety policy for children protection zones (Minsik Act) is effective in improving traffic safety by simply “strengthening legal regulations.” This strengthens the importance of traffic safety education to prevent drivers from engaging in driving behaviors such as illegal U-turns and traffic signal violations. It is necessary to ensure the traffic safety of children by establishing a truck operation policy that bypasses children protection zones.

PURPOSES : This study aimed to improve the effect of increasing the number of urban railway users when public transportation accessibility is improved by using village buses. METHODS : Using the case of Daejeon City, this study utilized the greenhouse gas reduction benefit among the benefits of the investment evaluation guidelines of the Ministry of Land, Infrastructure and Transport to demonstrate the effect of introducing village buses, a flexible means of transportation, to transportation-disadvantaged areas and improving accessibility, thereby inducing a change to urban railways. and were quantitatively analyzed. RESULTS : The number of users expected to switch to urban rail was 9,964 in 2020 and 9,220 in 2025. Thus, the greenhouse gas reduction effect is predicted to decrease annually by 34,554 t (2020) and 31,973 t (2025). CONCLUSIONS : Among the demand management techniques, reducing the use rate of passenger cars is one of the most important. For this policy, it is most effective to provide an alternative means of transportation.

PURPOSES : The objective of this study was to review roadway management strategies that can be utilized in the event of a radiological emergency, select feasible alternatives, and simulate a portion of the West Coast network to analyze the effectiveness of these strategies. METHODS : The methodology of the study involved reviewing the relevant literature, extracting the implications, establishing an analysis procedure, and selecting an effectiveness evaluation scale. Using a national transportation database, a network was constructed using Toba, a macroscopic model. RESULTS : A reverse-flow lane system was applied to the West Coast Expressway Glory IC–Hampyeong IC (total 25 km), and a plan to increase the number of lanes was applied to the Seokgyo Street–Shinpyeong Intersection on National Route 23 (total extension 28 km). Consequently, both road management strategies were found to be effective. CONCLUSIONS : This study examined roadway management strategies that can be utilized in the event of a radiological emergency, selected feasible alternatives, and simulated a portion of the West Coast network to verify the effectiveness of these strategies. In the case of reverse flow lanes, it is most effective when applied to expressways that can restrict the entrance and exit of vehicles. In the case of increasing the number of lanes, it is most effective when applied to general roads, and institutional arrangements should be made to enable two-way traffic to use the reserved shoulder lanes.

PURPOSES : This study establishes a methodology for evaluating traffic safety in response to the introduction of one-way traffic using surrogate safety measures and analyzes the impact of one-way traffic safety through a case analysis. METHODS : The SSAM(Surrogate Safety Assessment Measure) was used to analyze traffic conflicts (TTC(Time to Collision) and PET(Post Encroachment Time)), which are safety indicators. The SSAM input variable dataset was constructed using a VISSIM(Verkehr In Städten - SIMulationsmodell) simulation. RESULTS : Introducing one-way traffic rather than the pending issue (two-way operation) improved traffic safety as the possibility of TTC or PET was reduced. In addition, the analysis results showed that the average TTC time and average PET time increased with the introduction of the one-way system. It is anticipated that the avoidance action time taken by the driver to avoid dangerous situations will also increase, which will help improve traffic safety. CONCLUSIONS : As an alternative to solving traffic safety and communication problems occurring at the study site, it was determined that a one-way system would be effective. Furthermore, a one-way system that allows two-lane roads on both sides to move one-way and allows parking in pockets on both sides of the road would be appropriate.

PURPOSES : This study empirically analyzes the determinants of fatal accidents based on raw data on traffic accidents occurring in Chungnam in 2020. METHODS : Regression models based on theoretical arguments for fatal traffic accidents are estimated using a binomial logit model. RESULTS : The prediction model for fatal accidents is affected by the degree of urbanization of the region, month and day of the accident, type of accident, and type of law violation. In addition, speeding or illegal U-turns among law violations appear more likely to result in fatal accidents. The road surface conditions at the time of the accident do not show a significant difference in the probability of fatality among traffic accidents. However, the probability of a fatal accident is rather lower in case of a snowy road; this is plausible, as drivers tend to drive more carefully in bad weather conditions. CONCLUSIONS : Among traffic accidents, fatal accidents appear to be affected by the time and place of the accident, type of accident, and weather conditions at the time of the accident. These analysis results suggest policy implications for reducing fatal accidents and can be used as a basis for establishing related policies.

PURPOSES : The aim of this study is to develop a decision-making model for safety countermeasures based on the characteristics of water deer roadkills. METHODS : Through field investigation, 113 water deer roadkills with factors related to environment, geometry, and ecology were collected from May 2018 to April 2019. From the collected database, the characteristics of water deer roadkills were analyzed. An analytic hierarchy process was applied to establish a decision-making model to prevent water deer roadkills from appearing. RESULTS : The likelihood of water deer roadkills increases in summer and winter, road sections in suburban areas with low traffic volume, surrounding farmlands, and areas without illumination. The results show that factors such as safety, ecology, road geometry, policy consistency, and the willingness of the local government are critical factors for establishing the decision-making model. CONCLUSIONS : Appropriate safety countermeasures for water deer roadkills can be developed if the roadkill frequency, degree of sight distance restriction, speed limit for controlling overspeeding, roadkill severity, degree of forest area, traffic volume, and willingness of competent authorities are considered as essential variables.

PURPOSES: The purpose of this study is to analyze the elderly's preference for ride hailing (car sharing) services that use non-commercial vehicles and to identify the crucial factors influencing this preference. METHODS : Based on a literature review, a questionnaire was made to explore the preference of the elderly (over 65 years old) for ride hailing services. The survey was conducted in a rural area in Chungcheongnam-do. A total of 210 completed questionnaires were obtained. A binary probit model was applied to estimate the preference choice behavior. RESULTS: Monthly income, gender, age, and the time it takes to walk to the nearest bus stop were the main factors that influenced the preference for ride hailing services. The preference for ride hailing is likely to decrease when the monthly income of the elderly increase, and increase when the nearest bus stop is far away or as people get older. In addition, women had a stronger preference for ride hailing than men. CONCLUSIONS : For the elderly, ride hailing services can help them maintain their mobility and could be one of the countermeasures for demand-responsive transport from a sustainable perspective.

From comparing the impact dynamic absorber with the impact damper in the auxiliary vibration system with the conventional dynamic absorber, the following conclusions are obtained as follows ; 1. Recognizing that the amplitude restraining effect of the impact dynamic absorber become resonable in a comparison of conventional one development of an improved dynamic absorber may be probable. 2. With increasing the frequency ratio, the 1st resonance peak is higher but the 2nd one gets lower. In addition, the frequency ratio is peak located at the same resonance. 3. The optimum impact clearance is smaller and the vibration constraining effect becomes better with and increase in the mass of impact ball. And it is recognizable that the optimum tuning frequency ratio and impact clearance in an accordance with the mass ratio are varied. 4. The optimum tuning condition becomes gradually lower than the case of r=1 and maximum amplitude becomes lower with an increment in the mass ratio. However, the impulse clearance is larger and the working range of restraining vibration amplitude become smaller with a decrement in the mass of impact ball.

직선상 2층 구조물의 임의의 절점에 변위벡터가 불연속인 죠인트 요소를 갖는 경우, 면내 굽힘 자유진동을 해석하기 위한 알고리즘을 전달영향계수법에 의해 정식화하고, 간단한 모델에 의해 수치실험을 행한 결과, 다음과 같이 요약할 수 있다. (1) 전달영향계수법은 종래의 전달매트릭스법에 비해 계산정도 및 계산속도 양면에서 우수함을 확인할 수 있다. (2) 구조물의 임의의 중간 절점에서 상태벡터량(횡변위, 각변위, 전단력 및 모멘트 등) 중 일부의 물리량이 불연속성을 갖더라도, 알고리즘 자체를 변화시켜야 하는 전달매트릭스법과는 달리, 스프링전수 값의 조절만으로 간단히 처리할 수 있어, 알고리즘의 일반화 및 프로그램의 범용화가 가능하다. (3) 전달영향계수법에서는, 구조물의 중간에 반고정지지와 같은 단단한 탄성지지부가 다수 존재하는 경우에도, 기본적인 알고리즘을 변경할 필요 없이 전단 및 회전 스프링정수에 적당한 값을 대입하는 것만으로 중간조건에 대응시킬 수 있고, 모든 경계조건도 마찬가지로 처리할 수 있다.

주진동계인 외팔보의 자유단에 부진동계인 부가질량을 설치하여 부가질량의 크기와 충격 틈새 및 접촉면적을 변화시켜 그때의 진동진폭 특성을 실험함으로써 밝혀진 결과들을 요약하면 다음과 같다. 1) 부가질량의 상하 충격작용이 계의 진동진폭 감소에 상당히 큰 효과가 있으며 일종의 충격감쇠기로써 사용할 수 있음이 실험적으로 확인되었다. 2) 부가질량이 같을 때 충격틈새를 적절히 조정함으로써 진동진폭을 감소시킬 수 있다. 3) 충격 틈새가 일정할 때, 부가질량이 클수록 진동진폭은 감소하지만, 특정 조건에서는 부가질량이 작아도 진폭 감소효과가 크다. 4) 부가질량과 충격틈새가 일정한 조건에서 그 틈새가 작을 때 (1mm, 2mm) 부가질량의 접촉마찰면적이 클수록 진동진폭은 감소한다. 5) 계의 진동진폭 감소가 클 때, 주진동계와 부가질량의 진동진폭에는 위상차가 발생하며 충격감쇠 효과가 가장 클 때 위상차도 최대로 된다. 6) 일반적으로 부가질량이 클수록 진폭은 감소한다. 향후의 연구과제로서 충격시의 소음을 감소시키며 감쇠작용을 증가시키기 위해 접촉면에 적절한 방진고무를 설치하여 그때의 진동 감소 특성을 구명할 것이 요구된다. 이러한 일련의 기초연구를 통하여 목적으로 하고 있는 충격식 동흡진기의 설계 및 이에 대한 실험을 수행할 것이다.