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 : In the case of a turning maneuver at an at-grade intersection or changing the driving path, the trajectory of a vehicle with a long body, such as a large bus or an articulated bus, should be analyzed from the perspective of road design. In this study, an articulated bus was selected to analyze the off-tracking, swept path width, and lane encroach hment for vehicle turning. METHODS : In this study, four scenarios were developed for right- and U-turn situations. For the right-turn situation, cases were divided into radii of 15 m (Scenario 1) and 40 m (Scenario 2). For the U-turn situation, the cases were analyzed based on a U-turn after stopping at the stop line (Scenario 3) and without stopping at the stop line for the U-turn (Scenario 4). Each scenario was examined at 5° (Right-turn) and 10° (U-turn) angles to analyze the off-tracking, swept path width, and lane encroachment. In addition, four Global Positioning System (GPS) antennas were installed on top of the articulated bus to obtain the driving trajectory of the vehicle. GPS locational reference points were marked on the testing ground to improve positioning accuracy. RESULTS : As a result of the right-turn analysis at an intersection radius of 15 m (Scenario 1), the average off-tracking per angle was 1.04 m, the average swept path width was 3.89 m, and the lane encroachments occurred at an angle of 65° to 70°. For the right-turn analysis at an intersection radius of 40 m (Scenario 2), the average off-tracking per angle was 3.71 m, and the average swept path width was 3.31 m. Unlike the results for the 15-m radius, no lane encroachment was found. Furthermore, the averages of the off-tracking in the at-grade intersection U-turn situation were 2.65 m (Scenario 3) and 2.54 m (Scenario 4), and the average swept path width was 6.15 m. CONCLUSIONS : The required driving width when an articulated bus performs a turning maneuver at an at-grade intersection was analyzed, revealing the implications that must be considered for busway design.

PURPOSES : This study was conducted to analyze the driving width of the vehicle body and off-track width of front-rear tires when a large vehicle or an articulated bus passes through a roundabout. METHODS : The driving width was measured using two methods considering the off-tracking tire and the size of the vehicle body. The test conditions of the roundabout were considered as follows: number of entry/exit sections (three-legs roundabout and four-legs roundabout), number of lanes (one lane and two lanes), driving speed (10 km/h, 20 km/h, and 30 km/h), driving trajectory (centerline and maneuver), and driving path (right turn, straight, left turn, and U-turn). The driving trajectories of large buses or articulated buses were analyzed using a road design simulation tool (AutoTURN Pro). RESULTS : Consequently, it was observed that the driving width calculated using the off-track width of the front and rear tires was lower than that analyzed for the vehicle body. The width was smaller in the case of driving in the one-lane roundabout than that in the two-lane roundabout. In particular, it was analyzed that the situation in which the turning path invades the lane appeared in left-turn (East → South) and U-turn (East → East) situations. The width was narrower in the case of driving in the one-lane roundabout than that in the two-lane roundabout. CONCLUSIONS : The study results are expected to be applied for designing roads when large buses or articulated buses are selected as design vehicles.

PURPOSES : In this study, the installation standards for micro-roundabouts at the intersection of local streets with two entering lanes of a 3.0 m lane width were developed. METHODS : The inscribed circle diameter where a design standard vehicle could turn around safely based on the lane width and speed was analyzed using AutoTURN software. A total of 864 analysis scenarios for different entering volume and left-turning ratio (10%, 20%, 30%, and 40%), intersection type (three-way and four-way), heavy vehicle ratio (0%, 5%, and 10%), and circle lane turning speed (10, 15, and 20 km/h) conditions were established and evaluated. VISSIM Micro-Simulation was used to estimate the entering volume for microroundabouts with LOS C. RESULTS : The results showed that the estimated entering volumes of the three-way and four-way micro-roundabouts with LOS C were 300~400 and 200~400 vehicle/hour/lane, respectively. CONCLUSIONS : It is demonstrated that the standard volume of entering vehicles for micro-roundabouts is approximately 200 vehicle/ hour/lane, considering the number of approach lanes, designed speed of circulating lanes, left turn ratio, and heavy vehicle ratio.

PURPOSES : The purpose of this study is to establish design criteria for right-turning lanes by analyzing the relationship between the speed and geometry of right-turning lanes in urban areas. METHODS : A right-turn vehicle with a traffic island was surveyed for 32 geometries and 4,012 vehicles. Using multiple regression, we developed a running speed prediction model based on the running speed characteristics and geometry scale. RESULTS : According to the analysis of the running speed of the right-turning channel, the 85th speed was 34.5-38.3 km/h, depending on the right-turning lane radius, and 32.4-39.0 km/h, depending on the channel width group. Based on the multi-regression, the right-turning radius and the channel width variables were statistically significant because of the influencing factors of the road speed. Two independent variables were positive (+) coefficients. CONCLUSIONS : In this study, we investigated the running speed state on the right-turning channel and the factors that influenced the running speed. In addition, the relationship between the running speed and other factors was modeled through statistical analysis, and a running speed prediction model was established. It was observed that the driving speed increased as the geometry scale increased. Based on the derived running speed model, the maximum design criteria for limiting the speed of the conductive channelized right-turning lane in urban areas were established.

PURPOSES : The purpose of this study is to develop a service volume for signal metering on roundabouts to increase applicability of roundabout in Korea. METHODS: To develop the service volume for signal metering on roundabouts, traffic simulation studies were conducted using VISSIM software for various scenarios based on traffic volumes as approaches and location of detectors on controlling approach lane. Typically, the Vehicle Actuated Programming module in VISSIM was applied for analyzing more realistic traffic signal control conditions. RESULTS: As the left-turning volume is increased, the delay reduction rates were increased. And the case of 40 meter distance of a detector and 20 seconds red signal phase made better results. CONCLUSIONS: The signal metering on roundabout should be applied carefully because it is possible to lose roundabout strengthen in traffic operation aspect. The service volume for signal metering on roundabouts that suggested from this study is useful to decide the application of signal metering on roundabout.

PURPOSES: The goal of this study is the development of roundabout accident models for urban and non-urban areas. METHODS: This study performed a comparative analysis of the regional factors affecting accidents. Traffic accident data were collected for the period 2010~2014 from the TAAS data set of the Road Traffic Authority. To develop the roundabout accident models, the Poisson and negative binomial regression models were used. A total of 25 explanatory variables such as geometry, and traffic volume were used. RESULTS : The key findings are as follows: First, it was found that the null hypotheses that the number of accidents is the same should be rejected. Second, three Poisson regression accident models, which are statistically significant (p2 of 0.154 and 0.385) were developed. Third, it was noted that although the common variable of the three models (models Ⅰ~Ⅲ) is the number of entry lanes, the specific variables are entry lane width, roundabout sign, number of circulatory roadways, splitter island, number of exit lanes, exit lane width, number of approach roads, and truck apron. CONCLUSIONS: The results of this study can provide suggestive countermeasures for decreasing the number of roundabout accidents.

PURPOSES: The objective of this study is to establish the traffic volume-based warrants of right-turn lanes at unsignalized intersections and to introduce a risk probability methodology based on the warrants.METHODS : In this study, a risk probability of a potential rear-end collision is applied between a right-turn vehicle and the immediately following through vehicle. Using the shifted negative exponential model and the compound probability theorem, the risk probability can be expressed as the function of directional volumes and the percentage of right-turns for a two-lane and four-lane highway, respectively.RESULTS : Based on the risk probablity, guidelines for installing right-turn lanes on two-lane and four-lane highways were developed. The risk probability also showed rationality by comparing with right-turn same-direction conflicts observed in-situ.CONCLUSIONS : The results of our study define the total approaching volumes to encourage a right-turn lane as a function of operating speed, percentage of right-turn, and number of lanes.

신호교차로의 우회전 차로의 현 대기차량 길이 산정은     × × 과 같이 적용한다. 여기서, 길이계수 값(⍺)은 2.0이며 ‘lane overflow’가 일어날 확률이 대략 99%에 해당된다. N는 우회전 자동차의 수(신호 1주기당 도착하는 우회전 자동차)이며 S(m)는 대기하는 자동차의 길이이다. 그러나 이 방식은 도착하는 우회전 자동차의 수만을 기반으로 산정하며 대기차량 대수에 영향을 주는 다른 요인들(예를들면, 접근 교통량, 적색 신호시 우회전 가능 조건, 신호현시 조건 등)을 고려하지 않았다. 특히, 신호교차로에서 자주 발생하는 ‘lane blockage’현상을 고려하지 않았다는 점이다. 이로 인해 다양한 도로·교통 조건에서 현 대기차량 길이가 과대 혹은 과소평가 문제가 잠재적으로 존재한다고 판단된다. 이를 위해 Kikuchi와 Kronprasert 모델을 적용하여 우리나라의 도로·교통여건(신호운영 조건 포함)에 대응하는 신호교차로의 우회전 전용차로 길이를 산정하였다. Kikuchi와 Kronprasert 모델에 대해 신호교차로 접근로에서 4가지 대기패턴이 일어날 확률 계산과정은 다음과 같다. 첫 번째 단계는 적색 신호현시가 종료되는 시점에서 4개의 차량 대기 패턴(① ‘overflow’와 ‘blockage’현상이 발생하지 않는 조건, ② ‘blockage’현상이 발생할 조건과 그렇지 않는 조건, ③ ‘overflow’현상이 발생할 조건과 그렇지 않는 조건, ④ ‘overflow’와 ‘blockage’현상 발생하는 조건) 규명이다. 두 번째 단계는 각 차량 대기 패턴 경우별 확률 계산이다. 직진과 우회전 차량의 도착률과 허용 대기공간의 함수로서 각 패턴에 대한 확률 유도하며 적색현시동안 우회전이 가능하기 때문에 적색신호시 우회전 가능한 대수도 함수의 변수로 반영된다. 예를들면, 각 직진/우회전(i, j) 차량이 도착시 대기 패턴의 경우에 대한 확률은 다음과 같이 산정한다.          와  차량 도착 ×       와  차량 도착                     ,              여기서, i = 적색현시동안 도착하는 직진차량 대수, k = 적색현시동안 도착하는 우회전차량 대수 C = 우회전 차로의 허용 대기 길이(대수), = 적색현시당 차로당 도착하는 평균 직진차량 대수  = 적색현시당 차로당 도착하는 평균 우회전차량 대수 NR = 적색현시시 최대 우회전 가능한 대수, vc = 상충 교통량(대/시/차로) g/C = 유효 녹색시간비, tc = 임계간격수락(초), tf = 추종시간(초) 최종적으로 각 대기 패턴의 경우에 대한 확률값을 토대로                          ≥  혹은                    ≤   와 같이 우회전 전용차로의 길이를 산정한다. 여기서, ⍺ = ‘overflow’ 혹은 ‘blockage’가 발생하지 않을 확률 0.95이다. <그림 1>는 신호주기 90초와 유효녹색시간비(g/C)가 0.3에 대한 7개 ‘lane overflow’와 ‘lane blockage’ 현상에 대한 확률분포를 보여주고 있다. 이러한 각 도로·교통 조건별로 확률분포도를 산정하여 신호주기 90초, 120, 150초별, 직진 교통량과 우회전 교통량 관계를 기반으로 우회전 대기 차량 대수를 기 방식과 비교·평가하였다.

평면교차로는 잦은 사고가 발생하는 대표적인 지점이다. 경찰청의 교통사고통계(2016)에 의하면, 전체 사고중 약 90%가 교차로부근에서 발생하는 것으로 나타났다. 전체 교통사고는 지속적으로 감소 추세인 반면에 교차로내 발생하는 교통사고는 약 두 배 이상 증가하고 있다. 이는 교차로의 교통상충지점은 32개로 일반 구간에 비해 교통사고 발생할 확률이 높기 때문이다. 또한 직진 차량과 회전 차량 간 속도 차이가 크기 때문에 부상 심각도가 일반 구간에 비해 높은 것으로 판단된다. 이러한 교통상충형태 중에서 회전 차량의 감속으로 인해 뒤따르는 차량의 추돌사고는 적절한 보조차로 설치를 함으로써 어느정도 예방할 수 있다고 판단된다. 신호교차로의 경우는 한국도로용량편람의 서비스수준 분석방법론을 적용하여 보조차로 설치 여부를 판단할 수 있으나 비신호교차로의 경우는 보조차로 설치 여부에 대한 정량적인 가이드라인이 없으며 정성적 기준을 바탕으로 설계자 혹은 정책 결정자의 경험을 통해 보조차로 설치 여부를 결정한다. 특히, 비신호교차로의 우회전 전용차로에 대해 국내 관련 연구가 전무한 것으로 나타났다. ‘평면교차로 설계지침(2004)’에 의하면, 회전 교통량이 많아 직진교통에 지장을 초래한다고 판단되는 경우, 회전 자동차의 속도가 높은 경우, 교차각이 120도 이상인 경우는 전용차로 설치를 권장한다고 정성적 기준으로 제시하였다. 따라서 도로·교통 여건에서 적절한 보조차로 설계가 필요하다는 점을 고려한다면 정량적 기준도 어느정도 중요하다고 판단된다. 본 연구에서는 주도로의 우선 통행권을 부여하는 비신호교차로의 좌회전·우회전 전용차로 설치 권장 기준을 정립하기 위해 위험기반 확률 모델을 적용하는 방안을 고려하였다. 본 연구에서 적용한 확률모델은 Kikuchi와 Charkrobory(1991), Yang(2008), Mounce(1983)가 제시한 개념과 이론을 바탕으로 2차로와 4차로의 비신호교차로에 적용할 수 있는 모델로 재정립하였다. Kikuchi와 Chakroborty(1991)은 AASHTO에서 적용하고 있는 Harmelink 모델의 문제점을 지적하고 Harmelink 모델을 기반으로 수정된 모델을 제시하였다. Yang은 우회전 차량으로 인해 뒤따르는 직진차량과 잠재적 추돌 사고에 대한 위험을 분석하기 위해 개발된 모델은 Mounce에 의해 제안된 확률적 정의(Probability statements)를 기반으로 정립되었다. 이러한 확률모델을 통해 2차로도로와 4차로도로에 대해 좌회전·우회전 전용차로 설치 기준을 정립하였으며 아래의 그림은 몇 가지 경우에 대해 관련 기준을 제시하였다

회전교차로는 2000년도 시범사업을 시작으로 국내에 도입되기 시작하여 그 효율성과 안전성을 인정받아 점차 확대 설치되고 있는 상황이다. 현재 국내에 설치되는 회전교차로는『회전교차로 설계지침, 국토교통부, 2014』에 따라 설계되고 있으며, 다양한 설계요소에 대해 기준을 제시하고 있다. 그 중 가장 중요하다고 할 수 있는 회전교차로 설치를 위한 교통량 기준으로 12,000∼32,000대/일의 계획교통량을 제시하고 있으며 접근로 차로 당 125∼450대/시/차로로 제시하고 있다. 그러나 이는 회전교차로 용량에 지대한 영향을 미치는 좌회전 비율, 접근로 차로 수, 보행량 등이 고려되지 않은 교통량 기준으로 해당지역의 교통 및 기하구조 특성에 따라 회전교차로 용량은 큰 차이를 보일 수 있다. 즉, 좌회전 비율이 높을수록, 접근로 차로 수가 많을수록, 보행량이 많을수록 차로 당 용량은 떨어질 가능성이 크다. 이러한 교통 및 기하구조 특성을 고려하지 않고 회전교차로를 설치할 시 오히려 교통 흐름의 효율성이 떨어질 수 있어 회전교차로 설치 시 정확한 용량 산정은 매우 중요한 사항이다. 『도로용량편람, 국토교통부, 2013』에서는 상충교통량과 보행량을 이용하여 횡단보행자 영향계수를 산출하고 이에 따른 회전교차로 용량감소를 고려하고 있으며, 1차로형 회전교차로의 경우 상충교통량 0∼900pcph 범위 내에서 보행량에 따라 횡단 보행자 영향계수 0.6∼1.0을 적용하고 2차로형 회전교차로의 경우 상충교통량 0∼1,400pcph 범위 내에서 보행량에 따라 횡단 보행자 영향계수 0.6∼1.0을 적용하고 있다. 이렇듯 도로용량편람에서는 중요한 요소로 다루어지는 항목이 설계지침에서는 고려되고 있지 않으며, 설계지침의 기준은 현실과도 맞지 않는 실정이다. 본 연구는 기존 기침에 제시된 교차로 기하구조 및 교통여건이 고려되지 않는 보행량에 따른 회전교차로 전환기준을 보완하기 위해 일반적으로 가장 많이 설치되고 있는 4지 회전교차로를 기준으로 회전차로수 2 Level, 좌회전비율 6 Level, 교통량 10 Level, 보행량 9 Level에 따른 1080개의 시나리오를 설정하였으며, 시나리오별 VISSIM 시뮬레이션에 의한 교차로 평균지체시간과 도로용량편람의 회전교차로 용량분석 방법에 따른 교차로 평균지체시간을 산출하여 비교분석을 수행하였다. 그 결과, 회전교차로의 평균지체시간은 보행량, 상충교통량, 진입교통량, 좌회전비율, 회전차로수에 따라 변화됨을 알 수 있었으며, 분석결과를 이용하여 회전교차로 유형별 보행량에 따른 회전교차로 전환기준을 마련하였다.

PURPOSES :This study deals with traffic accidents involving trucks. The objective of this study is to develop a traffic accident model for trucks at roundabouts.METHODS :To achieve its objective, this study gives particular attention to develop appropriate models using Poisson and negative binomial regression models. Traffic accident data from 2007 to 2014 were collected from TAAS data set of road traffic authority. Thirteen explanatory variables such as geometry and traffic volume were used.RESULTS :The main results can be summarized as follows: (1) two statistically significant Poisson models (ρ2 = 0.398 and 0.435) were developed, and (2) the analysis revealed the common variables to be traffic volume, number of exit lanes, speed breakers, and truck apron width.CONCLUSIONS :Our modeling reveals that increasing the number of speed breakers and speed limit signs, and widening the truck apron width are important for reducing the number of truck accidents at roundabouts.

PURPOSES: The goal of this study is to analyze the operational efficiencies of special roundabouts using simulated programs. METHODS: This study primarily focuses on comparing the delays and traffic flow disturbances occurring at special roundabouts. In this study, the operational efficiencies of 450 scenarios (5 roundabout types × traffic volumes × directional ratios × measures) are analyzed according to the corresponding delays and traffic flow disturbances using VISSIM and SSAM. RESULTS : The main results are as follows: 1) the Hamburger roundabouts are determined to yield the least common-type delays, 2) the amount of delays at Turbo and Flower roundabouts with respect to relatively increased right-turn-type delays, in addition to the amount of delays at the Left-turn slip-lane roundabout with respect to relatively increased left-turn-type delays, are found to be reduced as compared to the common-type delays. Lastly, common- and increased right-turn-type traffic flow disturbances at the Turbo roundabout and increased left-turntype traffic flow disturbances at the Left-turn slip-lane roundabout are determined to be the most infrequent. CONCLUSIONS: This study comparatively analyzes five roundabout types: standard, Flower, Turbo, Hamburger, and Left-turn slip-lane. The effectiveness of roundabouts can increase according to given traffic volume, directional ratio, and measure of effectiveness.

OBJECTIVES : The objective of this study is to develop a traffic accident model of a roundabout based on the type of land use. METHODS : The traffic accident data from 2010 to 2014 were collected from the“ traffic accident analysis system (TAAS)”data set of the Road Traffic Authority. A multiple linear regression model was utilized in this study to analyze the accidents based on the type of land use. Variables such as geometry and traffic volume were used to develop the accident models based on the type of land use. RESULTS : The main results are as follows. First, the null hypothesis that the type of land use does not affect the number of accidents is rejected. Second, four accident models based on the type of land use have been developed, which are statistically significant (high R2 values). Finally, the total entering and circulating volumes, area of the central island, number of speed breakers, mean number of entry lanes, diameter of the inscribed circle, mean width of the entry lane, area of the roundabout, bus stops, and number of circulatory roadways are analyzed to see how they affect the accident for each type of land use. CONCLUSIONS: The development of the accident models based on the type of land use has revealed that the accident factors at a roundabout are different for each case. Thus, more speed breakers in commercial areas and an inscribed circle of proper diameter in commercial and residential areas are determined to be important for reducing the number of accidents. Additionally, expanding the width of the entry lanes, decreasing the area of the roundabouts in residential areas, and reducing the conflict factors such as bus stops in green spaces are determined to be important.

PURPOSES: There are many recently constructed roundabouts in Jeollabuk-do province. This study analyzed how roundabouts reduce the risk of accidents and improve safety in the province. METHODS: This study analyzed safety improvement at roundabouts by using an accident prediction model that uses an Empirical Bayes method based on negative binomial distribution. RESULTS : The results of our analysis model showed that the total number of accidents decreased from 130 to 51. Roundabouts also decreased casualties; the number of casualties decreased from 7 to 0 and the seriously wounded from 87 to 16. The effectiveness of accident reduction as analyzed by the accident prediction model with the Empirical Bayes method was 60%. CONCLUSIONS : The construction of roundabouts can bring about a reduction in the number of accidents and casualties, and make intersections safer.

PURPOSES : This study compared two measures of traffic flow effectiveness on roads with roundabouts and signalized intersections and determined the more appropriate measure. METHODS: In addition to average delay time, the conventionally used measure, average travel time was introduced to measure traffic flow effectiveness because it is able to be obtained through field survey and reflect different travel distances and speed limits of roundabouts and signalized intersections. Using the two measures, roundabouts and signalized intersections were compared through simulations in terms of traffic flow effectiveness. RESULTS : For one-way single-lane roads, the two measures indicated consistent results that roundabouts were more effective than were signalized intersections when the traffic volume was less than 300 vphpl but vice versa when it exceeded 450 vphpl; however, the measures yielded inconsistent results when the volume was 350~400 vphpl. For one-way double-lane roads, the two measures indicated consistent results that roundabouts were more effective than were signalized intersections when the volume was less than 200 vphpl but vice versa when it exceeded 400 vphpl; however, the measures yielded inconsistent results when the volume was 250~350 vphpl. The results obtained using the two measures differed substantially for double-lane roads because behaviors such as weaving and lane changing at roundabouts are more common in double-lane roads than in single-lane roads. CONCLUSIONS : The average delay time would be lower on roads with roundabouts, but average travel time would be lower on roads with signalized intersections. Thus, evaluating the relative effectiveness of roads with roundabouts and signalized intersections by using average delay time alone would be inappropriate, whereas using average travel time as the evaluation index would yield fairer results.

2010년 우리나라는 교통운영체계 선진화 방안의 일환으로 교통지체 및 교통사고 잦은 지점을 중심으로 일반 평면 교차로에서 회전교차로(Roundabout)을 도입하였으며, 현재 전국적으로 약 400개소가 운영 중 이다. 국내･외의 급격한 회전교차로 증가는 회전교차로의 독특한 기하구조와 운영방식에 의해 교통소통 및 안전 개선에 획기적으로 기여하는 했다는 점이다. 국내에서는 회전교차로 설치 전 대비 교통사고 발생 건수 평균 약 40% 감소, 통행시간 평균 약 30% 감소하는 것으로 나타났으며, 국외의 경우에서도 회전교 차로 도입에 따른 교통사고가 설치전보다 30~80% 감소된 것으로 나타났다. 비록 다양한 도로･교통 환경 에서 자동차 통행이 가능하기 위해 2014년에 회전교차로의 설계기준을 개정되었지만, 국외에 비해 더 제 약적인 국내 도로 환경에서 적용 가능하기 위해 더 유여한 설계 방안을 제시할 필요가 있다. 회전교차로 의 설계 요소들(내접원, 중앙교통섬, 회전차로 폭, 진출입 차로 폭 및 회전반경)은 설계자동차와 연관성이 상당히 높으며, 건설비용, 안전 혹은 운영측면과도 밀접한 관계가 있다. 따라서 적절한 설계기준 제시는 인프라 성능･안전 적정 유지와 공사비용에 중요하다. 그러나 너무 보수적인 설계기준을 적용한다면 지나 친 건설비용 혹은 높은 속도에 따른 안전문제가 발생할 수 있다. 본 연구에서는 접근로 중심선 방향이 회 전교차로의 중심을 향하도록 하는 방식 대비 회전교차로 중심의 왼편으로 편형에 따른 진출입 차로 폭과 회전반경 영향 정도를 정립하여 유연한 기준 값 적용 가능성을 분석하였다. 차량의 주행 궤적 분석 시뮬 레이션 프로그램(AutoTURN)을 이용하여 1차로형 회전교차로(설계기준자동차:세미트레일러)와 2차로형 회전교차로(설계기준자동차:대형자동차+세미트레일러)의 각각 한 가지 설계조건(내접원 지름)을 대상으 로 편형에 따른 관련 설계요소들에 미치는 영향을 분석하였다. 시뮬레이션 결과, 접근로 중심선 방향이 회전교차로 중심을 향하도록 하는 방식 대비 그 중심의 왼편으 로 편형에 따른 방식이 같은 회전반경에서 진입차로 폭을 상당히 감소시키는 것으로 나타났다. 특히 편형 이 클수록 그리고 2차로형 회전교차로에서 관련 영향정도가 더 큰 것으로 나타났다. 이러한 편형 방식을 통해 공사비용 절감뿐만 아니라 좁은 차로 폭으로 인한 접근 차량 속도 감소를 유도하여 안전효과도 기대 할 수 있다고 판단된다.