PURPOSES : Under the Traffic Safety Act, the installation and management of transportation facilities (facilities and attachments necessary for the operation of transportation, such as roads, railways, and terminals) must take necessary measures to ensure traffic safety, such as enhancing safety facilities. Recently, railway operators have graded the congestion level inside railway stations and vehicles, addressing safety and convenience issues arising from congestion and providing this information to users. However, for bus-related transportation facilities (such as bus stops, terminals, and transfer facilities), criteria and related research for assessing traffic congestion are lacking. Therefore, this study developed a model for the congestion risk factors of four bus-related transportation facilities and proposed criteria for classifying congestion risk levels. METHODS : This study involved selecting congestion risk influence variables for each traffic facility through field surveys, calculating congestion risk index values through evacuation and pedestrian simulations, and constructing a congestion risk influence model based on the ridge model. RESULTS : The factors influencing congestion were selected to include the number of people waiting, effective sidewalk width, and number of bus stops. As a result of developing congestion risk grades, the central bus stops were determined to be in a severe stage if the Average Waiting Time (AWT) was 2.7 or above. Roadside bus stops were considered severe at 4.2, underground metropolitan transit centers at 3.7, and bus terminals at 5.9 or above. CONCLUSIONS : This study can help establish a foundation for a safety management system for congested areas in transportation facilities. When the congestion risk prediction results correspond to cautionary or severe levels, measures that can reduce congestion risk must be applied to ensure the safety of road users.

Passengers on public buses operating in the metropolitan area are exposed to the closed indoor air for minutes to hours. The indoor air quality of buses is mostly controlled through ceiling-mounted ventilation and filtration devices. A simulation study using a commercial code was conducted for fluid flow analysis to evaluate the potential effectiveness of an air purifier that can be inserted into bus windows to supply clean air from the outside to the inside. As a result of field measurements, the average CO2 concentration inside the bus during morning and evening rush hours ranged from 2,106±309 ppm to 3,308 ± 255 ppm depending on the number of passengers on board. This exceeded the Guideline for Public Transportation. The optimal installation position of an air purifier appeared to be the front side of the bus. In fact, even a low diffusing flow velocity of 0.5m/s was effective enough to maintain a low concentration of CO2 throughout the indoor space. Based on numerical analysis predictions with 45 passengers on board, the maximum CO2 concentration in the breathing zone was 2,203 ppm with the operation of an air purifier.

PURPOSES : Most Red bus1) (metropolitan bus) routes to Seoul need to increase supply by increasing the number of buses and number of trips because of the high level of congestion in buses, which also accommodate standing passengers. Due to the recent Itaewon disaster, people have been banned from standing on Red buses due to concerns over the excessive use of public transportation, adding to the inconvenience of passengers, such as increased travel time. However, some routes incur a large deficit owing to excess vehicles and trips relative to the number of passengers, thereby increasing the financial burden of Gyeonggi. Therefore, in this study, a reasonable operation plan is required based on the demand on Red bus routes. METHODS : Using accurate data from smart cards and a Bus Management System, the model was applied to consider bus usage, bus arrival distribution, waiting time, and operating conditions, such as actual bus usage time and bus dispatch interval. RESULTS : As a result of applying the model, buses between 7:00 and 9:00 and 16:00 and 18:00 were very crowded because of standing passengers, and passenger inconvenience costs decreased because of the longer waiting times for bus stops in Seoul. Currently, there are 15 buses in operation for the red bus G8110. However, considering the annual transportation cost, transportation income, and support fund limit, up to 12 buses can be operated per day. The G8110 route was analyzed at 23.6 million won for passenger discomfort cost, as 15 buses operated 97 times per day on weekdays. However, when establishing optimal scheduling, 12 buses per day operated 75 times per day, with a 19.7 million won passenger discomfort cost. CONCLUSIONS : As all red buses run from the starting point, passengers at the bus stop wait for more than an hour before entering Seoul, and the passenger discomfort cost of using demand-responsive chartered buses decreases only when commuting from Jeongja Station and Namdaemun Tax Office stops. Currently, many people commuting from Gyeonggi-do to Seoul are experiencing significant inconvenience owing to the ban on standing in Red buses; a suitable level of input can be suggested for the input and expansion of chartered buses.

Numerous studies have attempted to predict the energy output of solar-powered vehicles based on different parameters such as road conditions, driver characteristics, and weather. However, since these studies were conducted on stationary vehicles, they are limited in their accuracy when applied to driving vehicles. This study aimed to improve the accuracy of electric power prediction for a solar-powered bus by applying a technique that improves energy efficiency without affecting driving performance. A comparative analysis of power generation and solar irradiance data was conducted for the bus driven on different roads to forecast its power generation, and a high-accuracy power generation prediction equation was derived. A comparison with actual test results revealed that a power generation forecast accuracy of at least 90% was achieved, validating the equation used for forecasting. With this power generation prediction process, it is possible to forecast the amount of energy generated in advance when a solar bus is operated in a specific area.

In the wire constituting the LIN, which is one of the vehicle communication devices, disconnection of the wire or contact resistance of the circuit occurs due to vibration and aging of the vehicle. This affects the entire communication network and may have a significant impact on the safe driving of the vehicle as information is not transmitted. In this study, a LIN BUS circuit simulator was built on its own like a real car and measured with an automotive oscilloscope instead of a common method of measuring and diagnosing a circuit with a multimeter in the event of a LIN BUS circuit failure. Referring to the experimental results, it will be possible to diagnose faults in circuits efficiently and quickly.

The purpose of this study was to develop a side protection device for school buses for children. In the case of the door side impact beam, it plays a very important role because it protects passengers from external collisions. However, in the case of a school bus for children, the space between the door and the door trim is very narrow, unlike a general passenger car. So, as an alternative to this, we are trying to develop Rub Rail, which is compulsory for children's school buses in the United States. Based on the results of structural analysis according to the cross-sectional shape of the rub rail, we want to find out the appropriate shape of the rub rail.

목적 : 본 연구의 목적은 저상버스 이용현황을 파악하고, PEO 모델기반 해석 과정을 통해 개인적, 작업적, 그리고 환경적인 부분의 잠재적 문제 요인을 파악해보려고 한다. 연구방법 : 본 연구는 지체장애 및 뇌병변 장애를 경험하고 있는 48명의 대상자를 중심으로 설문조사를 실시하였 고, 장애인이 저상버스를 이용하는데 어려운 요인들을 PEO모델로 분류하여 해석하였다. 결과 : 본 연구결과, 작업과 환경요소에서는 운전자의 지원부족 및 승, 하차 과정의 작업수행문제가, 사람과 환경 요소에서는 이용자의 사회적 통합시도의 부족, 낮은 보조기기 사용률과 사회적 인식수준의 문제가, 사람과 작업 요소에서는 이용자의 건강상태 및 장애에 대한 부정적 인식과 성공적인 작업수행의 경험 부족이 잠재적인 문제 요소로 확인되었다. 결론 : 이동권 보장을 위한 서비스 개선을 위한 노력은 매우 중요할 것이며, 향후, 다각적인 분석을 통한 저상버 스 이용자의 서비스 개선을 위한 노력이 필요할 것이다.

PURPOSES : The turning movement of vehicles is directly affected by such factors as vehicle length, wheelbase, steering angle, articulated angle, and wheel steering. Therefore, it is necessary to analyze the impact of changes in each factor on the turning of the vehicle. Because a vehicle with a long body, such as an articulated bus, makes a wide turn, this study analyzes the swept path of the driving vehicle considering the specifications of the vehicle. METHODS : This study was conducted by dividing driving routes into four routes of two-lane four-way roundabouts, and the turning conditions were examined for six types (Type 1–6) that simulated actual articulated bus data. The same vehicle specifications as those of the actual articulated bus were applied to the road design simulation (AutoTURN Pro), and the width of the swept path for the articulated bus was investigated based on the wheel steering control. Using a virtual reference line for dividing the inscribed circle into lanes of the roundabout by 5°, the driving width of the swept path was measured and the angle at which the driving width was largest during driving through the turning intersection was examined. In addition, the changes in the driving width of the swept path according to the wheel steering control under the same wheel turning conditions, as well as the articulated and steering angles, were investigated. RESULTS : The driving width of the swept path for the vehicle (Type 1) with the front wheel control function being an all-wheel system was less than that of an articulated bus with the largest driving width of 15° after entering the roundabout and 15° before entering the roundabout (Type 2). Furthermore, although the specifications of the vehicles were the same, it was determined that Type 5 was superior to Type 6 after reviewing the driving width in light of changes in the steering and articulated angles. CONCLUSIONS : The results of this study are expected to contribute to the field of road design considering traffic safety when large vehicles, such as articulated buses, turn on roundabouts or curved road sections.

PURPOSES : Presently, it is impossible to evaluate the actual number of operational plans and punctuality of bus routes. In this study, a methodology for separating bus stops and sorting departure orders was developed using city bus operation information, and its field applicability was examined. METHODS : Based on current bus data, the "moving speed (km/h)," "Lag data," and "Lead data" were generated. The number of stops was classified based on the location where the order of the stops changed for each vehicle, and an arbitrary ID was assigned for each number of stops. In the case of a preceding vehicle, for each rotation information, a time interval was calculated based on the same point, and the rotation with the smallest time interval was determined as the preceding vehicle. RESULTS : An evaluation was conducted on Bus Route 201 in Daejeon. The vehicles were classified based on the operation data of the previous day. From analyzing the operation time and distance for each operation based on the last stop and starting point, it was found that both the number of operation plans and performance were consistent. The punctuality was analyzed and was found to be inversely proportional to the difference between the stop arrival time and preset arrival time, preset dispatch interval, and actual dispatch interval. The on-time(regularity) ratio was determined as 98.0% and the early departure ratio was 99.3%, indicating very good regularity. CONCLUSIONS : The research results can be used by local governments with insufficient levels of public transportation-based data management, and can be used as basic data for establishing public transportation policies. The results of this study can be referred to when evaluating the transparency of financial support for public transportation operators and operations, with the aim of enhancing public transportation services.

Seoul has installed mechanical air filters in the heating, ventilation, and air conditioning (HVAC) systems of city buses to improve their indoor air quality since late 2019. We evaluated particle removal efficiencies of the filter in a wind tunnel, and clean air delivery rates (CADRs) of the systems and a household air purifier in the buses, following the test standards. The filter showed the efficiencies of 91% and 97.6%, 88% and 97.9%, and 78% and 95.2% for 0.35 μm particles and PM2.5 at 1.0m/s, 1.5m/s, and 2.0m/s, respectively. The efficiencies rose with an increase in the particle size and the filters had a minimum efficiency reporting value (MERV) rating of 15. The CADRs for PM2.5 and flow rate of the systems were 12.7m3/min and 17.9m3/min, 16.6m3/min and 25.4m3/min, 18.7m3/min and 33.6m3/min, and 23.3m3/min and 47.1m3/min on the operation mode of 1, 2, 3, and 4, respectively. The CADRs of the systems were 3.8-7.1 times higher than those of the air purifier, but single-pass removal efficiencies of the former were 0.56-0.81 lower than those of the latter.

이 연구는 전염병의 잠재적 확산 가능성이 높은 지역의 탐색을 목적으로, 코로나19 전후의 버스 네트워크 클러스터의 시공간적 변화를 분석한다. 분석방법으로는 Getis와 Ord의  통계를 공간 네트워크로 확장 및 적용한  통계 값을 사용하였다. 이 과정은 서울시 전체 버스 네트워크의 개별 흐름에 대해 각각 적용되기 때문에 대규모 연산을 위해 병렬컴퓨팅 방식을 적용한 슈퍼컴퓨터를 사용하였다. 연구 결과, 첫째, 코로나19 이후 버스 네트워크가 일부 흐름으로 집중된 경향을 보였다. 둘째, 코로나19이 후의 버스 흐름은 주거지, 농업지로의 이동은 증가하고 상업지역, 교통지역으로의 이동은 감소했음을 확인하였다. 셋째, 중심업무 지구 중 여의도 방면의 클러스터, 구로디지털단지역 방면의 클러스터와 달리, 강남일대는 코로나19 전후의 유의미한 변화가 나타나 지 않았다. 이 연구는 국내에서 처음으로 코로나19전후의 버스 네트워크 클러스터를 확인하고 변화 특징을 제시한다는 의미가 있다.