PURPOSES : There are generally various driving behaviors in toll collection areas, including lane changing, merging and diverging, and other behaviors. Because of these behaviors, accident risk and traffic congestion may occur. To mitigate these problems, multi-lane electronic toll collection systems have been developed with a high-speed limit of 80 km/h. This study was conducted to investigate travel speed changes and effects through multi-lane electronic toll collection systems with a high-speed limit. METHODS : Traffic simulations were conducted using VISSIM. Before conducting simulations, driving behavior around the toll collection areas was observed, and field data were collected based on drones for peak and non-peak hours. In addition, safety effect evaluations were conducted based on conflict analyses using the SSAM software. RESULTS : Through multi-lane electronic toll collection systems with a high-speed limit, the travel speed on the toll collection area was increased, and traffic operational efficiencies were identified. However, different speed variations were produced as observation locations in toll collection areas. Speed variations were mitigated at most locations except the area within the tollbooth because of the high speed limit for multi-lane electronic tollbooth. CONCLUSIONS : It was important to manage lane-changing activities, and this may influence traffic operational effects. Safety effects were also identified through conflict analyses.

PURPOSES : In this study, we review the method and equations suggested in the usual guidelines to calculate the lane widening for curved sections, and proposed values of the widths and the amount of widening that reflected the driving trajectory of an articulated bus. METHODS : A simulation was used to obtain the trajectory of articulated bus, which is adequate for a Super-Bus Rapid Transit(S-BRT) service with the longest length of the design vehicle. This study was conducted by dividing the trajectory into curved and tangential sections, and the extent of widening was analyzed by changing the rotation angle by 5°. In addition, the results related to the amount of widening from the conducted analysis were applied to particular situation of right turns of an articulated bus at urban intersection. The possible conflict situations that may occur were analyzed. RESULTS : When analyzing the rotation angle at which the size of the driving width was set to be the largest for each lane center radius, the rotation angle for a lane center radius ( =15m) was 35°, the rotation angle for a lane center radius ( =20m) was 45°, the rotation angle for a lane center radius ( =25m) was 55°, and the rotation angle for a lane center radius ( =30m) was 60°. CONCLUSIONS : As the radius increases, the required driving width and the amount of widening decrease. The rotation angle that requires the largest driving width is presented. The results show that as the central radius ( ) of the lane increases, the amount of widening for each rotation angle decreases. In addition, based on the results of the analysis of the driving width for each rotation, the trajectory of an articulated bus was applied to an at-grade intersection to check the distance required for widening from the beginning point of the curve.

PURPOSES : The objective of this study is to determine the characteristics of nitrogen oxide (NOx) concentration in an exclusive median bus lane station. The hourly variations of NOx concentration and the effect of traffic volume on NOx concentration were analyzed using NOx measurement data and the number of vehicles at the station. METHODS : Data were collected using the chemiluminescence method for NOx concentration. Atmospheric information and traffic volume of buses were collected from the Korea Meteorological Administration and Bus Information System, respectively. RESULTS : As a result, the NO2 concentration in the test section was found to have a strong correlation with those in the atmospheric measurement station located near the test-bed. In addition, the average NOx concentrations in the test section were significantly higher than those of the other monitoring stations due to bus emissions. The average NOx concentration in the exit section was higher than that in the entry section owing to the vehicle’s frequent stops and fuel consumption due to acceleration. During the measurement period, the average NOx concentration was measured as approximately 33 % higher in the exit section than in the entry section. In addition, the NOx concentration at the bus station was found to increase as the bus dwell time increased, rather than the number of bus passages. CONCLUSIONS : This study provides clear characteristics of the NOx correlations with traffic information in an exclusive median bus lane station. It was shown that the NOx concentration at the bus station increased as the number of passes and bus dwell time increased. According to the coefficient of determination, the dwell time is more closely correlated to the NOx concentration at the bus station than the number of bus passes, indicating that it is a better parameter for predicting NOx concentration at bus stations.

PURPOSES: The purpose of this study is to compare the lane curing time of natural drying and a lane drying device when painting lines on a highway. METHODS: The painting process was carried out in July 2015 and September 2015, respectively, for the Gimcheon IC - Gimcheon JC. After the painting, measurements were obtained three times at six measurement points located at 20 m intervals on the shoulder line and the dividing line. The curing time was measured for natural drying and drying using a lane drying device, and compared for different pavement types (asphalt, concrete) and paint types (waterborne paint, methyl methacrylate paint). RESULTS : The results of the lane curing time comparison on the highway are as follows. The combination of asphalt and methyl methacrylate paint cured more rapidly during both the natural drying and drying using the lane drying device. Finally, it was cured at least 32.2% and 40.7% faster when using a drying device than in natural drying. CONCLUSIONS: The comparison of lane curing time of the highway showed that the combination of asphalt and methyl methacrylate paint cured more rapidly when using both natural drying and a lane drying device.

The Golden Gate Bridge, known as one of the most beautiful bridges in the world, serves 110,000 vehicles per day, connecting San Francisco to inland as a segment of Highway 101 in California. The average peak hour volume over 6,500 vehicles per hour exceeds the traffic capacity of three lanes on each direction. Due to unique function of the bridge as a gateway of San Francisco, the peak directions in the morning and afternoon were explicitly distinguished. Recurrent traffic delay on the peak direction deteriorated level of service during the commute periods and caused user’s inconvenience and traffic accidents. The workers previously used to move plastic delineators to change lane configuration (4-2, 3-3, and 2-4) in several times a day. Neither did it provide prevention nor physical protection from the head-on collision on the bridge section. In January 2015, the Golden Gate Bridge was completely closed for two days to install the moveable median barrier (MMB) system, Road Zipper®, for more effective and safer variable lane management than the previous operation. One-meter section with 30.48 cm wide of highly reinforced concrete barriers are linked to form a continuous barrier wall and the machine lifts and passes the barriers through a conveyor system at a seeds up to 16 km/h. The MMB enables to quickly reverse lane configuration without traffic closure, providing more lanes to the peak direction as well as eliminating head-on collision on the bridge deck by presence of a physical structure. The traffic monitoring study result shows the significant improvement of average speed during peak hours and the regional traffic accident records shows improvement of safety after implementing the MMB on the Golden Gate Bridge. According to the traffic accident records, 13 injuries occurred in five accidents of vehicle collision in two-directions from 2007 to 2014 but no two-way accident has been reported since the operation of the Road Zipper® began. Furthermore, the MMB would be effectively implemented on construction work zones, managed lanes, variable lane management and other traffic operation to improve traffic safety and maximize utilization of roadway facilities.

PURPOSES : The purpose of this paper is to analyze the change in lane reflection performance through lane washing and sweeping on highway lanes. METHODS: This paper compared and analyzed the changes in lane reflection performance before and after lane washing and sweeping. The research method was as follows. First, we selected four research sites on the Gyeong-bu Highway. Second, the parameters affecting lane reflection performance are classified into luminance, brightness, and number of glass beads. Third, the change in reflection performance was measured after washing /sweeping at the same place after studying 60m of the unwashed/unswept area. Fourth, the measurement results were compared and analyzed before and after lane washing/sweeping. RESULTS: The results of this study are as follows. First, lane washing improved the luminance and brightness by 4.2~21.4% and 1.4~5.1%, respectively, and reduced the number of glass beads per wash by 0.2~1.2%. Second, lane sweeping improved the luminance and brightness by 2.3~8.5% and 0.8~2.3%, respectively, and reduced the number of glass beads per sweep by 0.8~4.9%. CONCLUSIONS : By comparing the results of lane washing and sweeping, it was found that compared to lane sweeping, lane washing improved the luminance and fewer glass beads were dropped.

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 supports the evidence that it is possible to rehabilitate a damaged pavement with a lane closure specifically based on the Gimcheon~Sunsan project. METHODS : The prediction results from the simulation programs were compared with field monitoring, which focused on traffic management planning, congestion (length, time, and passing speed), bypass, and user cost, among others. RESULTS : The research results showed that lane closure application and pavement repair of the aged pavement in Korea were possible, even though the prediction results were minimally different from the field monitoring. The road agency contributes to service life extension of the rehabilitated pavement using this method. CONCLUSIONS: A marginal effect caused by the lane closure was observed on travelling users or vehicles, and the user cost of pavement repair decreased. Therefore, introducing the repair method or rehabilitation in Korea is possible. Information dissemination through various media was properly done to execute the project well. Moreover, the construction area traffic utilized nearby alternative roads. Therefore, improving the repaired pavemen’s service life while ensuring that the pavement management agency can provide a road with comfortable user riding quality was possible.

PURPOSES : The purpose of this study is to present a linear programing optimization model for the design of lane-based lane-uses and signal timings for an isolated intersection. METHODS: For the optimization model, a set of constraints for lane-uses and signal settings are identified to ensure feasibility and safety of traffic flow. Three types of objective functions are introduced for optimizing lane-uses and signal operation, including 1) flow ratio minimization of a dual-ring signal control system, 2) cycle length minimization, and 3) capacity maximization. RESULTS : The three types of model were evaluated in terms of minimizing delay time. From the experimental results, the flow ratio minimization model proved to be more effective in reducing delay time than cycle length minimization and capacity maximization models and provided reasonable cycle lengths located between those of other two models. CONCLUSIONS : It was concluded that the flow ratio minimization objective function is the proper one to implement for lane-uses and signal settings optimization to reduce delay time for signalized intersections.

PURPOSES : It is well known that experts determined the current standard dimensions of freeway lane markings. However, rigorous engineering rationale could be insufficient regarding whether or not the standard dimensions account for how visible the markings are to the driver. In this study, we seek to optimize the dimensions of freeway lane markings to improve their visibility to drivers. METHODS: The study was conducted as follows. First, alternative lane marking dimensions were selected which could be installed in a test construction site. Second, a video recording was made while driving on the test construction site. Third, subjects were shown the recorded video and then instructed to indicate their preference from among the various lane markings. Lastly, t-tests were applied to assess the statistical significance of differences in the preferences expressed. RESULTS : According to the t-test results, there was no significant difference in the preferences expressed regarding the lane marking widths. However, with regard to the dimensions of freeway lane marking, which represents line marking lengths, gap lengths, and widths of marking, the subjects expressed a preference for specific dimensions such as 6 m:12 m,13 cm, 8 m:12 m,10 cm and 6 m:12 m,10 cm. CONCLUSIONS : In considering the dimensions of freeway lane markings and their relation to visibility by the driver, it was found that dimensions such as 6 m:12 m,13 cm, 8 m:12 m,10 cm and 6 m:12 m,10 cm.

PURPOSES : The purpose of the study is to a) explore the operating speed of trucks on rural highways affected by road geometry, and thereby b) develop a predictive model for the operating speed of trucks on rural highways. METHODS: Considering that most of the existing studies have focused on cars, the current study aimed to predict the operating speed of trucks by conducting linear regression analysis on the speed data of trucks operating on the linear-curved-linear portions of the road as a single set. RESULTS: The operating speed in the plane curve portion increased with the length of the curve, and decreased with a lower vertical grade and a smaller curve radius. In the straight plane portion, the operating speed increased with a larger curve radius(upstream), and decreased with an increase in the change of the vertical grade, depending on the length of the vertical curve. CONCLUSIONS: This study developed estimation models of truck for operational speed and evaluated the degree of safety for horizontal and vertical alignments simultaneous. In order to represent whole area of the rural highway. the models should be ew-analyzed with vast data related with road alignment factor in the near future

PURPOSES: This study was done to model the headway distribution of rural two lane roads. METHODS: Time headway data for the various level of traffic volumes was measured in twelve sites. Based on the time headway data, existing seven mathematical models were evaluated and selected by comparing graphically the measured and theoretical distributions and conducting the Chi-square test. RESULTS: The results show that both the Schul model and Composite Model were the most appropriate models of the models. Based on the measured time-headway distributions, this study proposed a new headway distribution model by the shift of the Schul model. CONCLUSIONS : The shifted Schul model has the ability to describe time headway distirbutons for random, intermediate, and constantheadway states.

PURPOSES: The lane width of the domestic highway is 3.5 ~ 3.6m and it has been designed nationwide. However, the distribution of the average vehicle widths, rearview mirror widths and lateral wheel paths by region appear different. Then, lane spare widths may differ by region followingly. Thus, the flexible design of freeway lane widths is required. METHODS: The methodologies of this paper are as follows. First, vehicle widths·rearview mirror widths·lateral wheel paths of vehicles driven four national expressways were measured. Second, lane spare widths by vehicle widths were calculated. Third, lane spare widths reflecting rearview mirror widths were calculated by using interval estimation. Additionally, lane spare widths reflecting vehicles lateral wheel paths were calculated. RESULTS : The results of this paper are as follows. First, lane spare widths by vehicle widths ranges 0.83 to 0.95m. Second, lane spare widths reflecting rearview mirror widths ranges 0.518 to 0.747m at the confidence interval 95%. Third, lane spare widths reflecting vehicles' lateral wheel paths ranges -0.022 to 0.322m at the curved sections and the confidence interval 95%. CONCLUSIONS: It may be concluded that the present lane spare widths are relatively narrow at the curved section. Thus, there is a need to consider expanded lane widths at the curved sections. Additionally, there is a need to consider flexible design of lane widths by various conditions.

PURPOSES : The lack of details of design guideline for zig-zag shaped section approaching central bus stop leads an traffic accident proneness. So, this study analysed the geometric elements of central bus stop area in terms of vehicle dynamics and suggested design alternatives. METHODS: The study analysed a dynamic behaviour of bus moving in and out of zig-zag shaped section using Auto-Turn under scenarios. Based upon dynamic analysis, the study found out the width of overtaking lane is the most influential factor for a safe moving at zig-zag alignment. RESULTS : The width of overtaking lane at design speed of 40, 50, and 60 km/h respectively was suggested given taper ratio of 1 to 10 required for Bus Rapid Transit (BRT), and the lane width is not wider than 4.0m which possibly makes two vehicles using the same lane. Also, the width of overtaking lane which mitigates the taper ratio was suggested with the same restriction about the maximum lane width. CONCLUSIONS: The results of the study can be used to prepare a design guideline on zig-zag shaped alignment of central bus exclusive lanes. The more stable moving is expected by applying the design alternatives suggested, therefore the lower rate of traffic crashes at the vicinity of central bus stops.

PURPOSES : The purpose of this study is to propose delay-minimizing operation methodology of a signalized intersection based upon optimization of lane-uses on approaching lanes for an intersection. METHODS: For the optimization model of lane-uses, a set of constraints are set up to ensure feasibility and safety of the lane-uses, traffic flow, and signal settings. Minimization of demand to saturation flow ratio of a dual-ring signal control system is introduced to the objective function for delay minimization and effective signal operation. Using the optimized lane-uses, signal timings are optimized by delay-based model of TRANSYT-7F. RESULTS : It was found that the proposed objective function is great relation with delay time for an intersection. From the experimental results, the method was approved to be effective in reducing delay time. Especially, cases for two left-turn lanes reduced greater delays than those for a left turn lane. It is noticed that the cases for different traffic volume by approach reduced greater delays than those for the same traffic volume by approach. CONCLUSIONS : It was concluded that the objective function is proper for lane-uses optimizing model and the operation method is effective in reducing delay time for signalized intersections.

한국정부는 완도부근에 특별히 항로를 지정하였다. 규정에 따르면 선박은 항로의 지정된 방향을 따라 항해하여야 한다. 한편, 본 완도지정항로에는 서로 횡단하는 두 개의 항로가 설정되어있다. 한국의 해양안전심판원은 선박충돌이 발생한 원인에 대한 판단을 하였다. 항로지정방식에 적용되는 항법이외에도 횡단항법이 추가로 적용되는지가 쟁점이 되었다. 지방해양안전심판원은 횡단항법을 우선적으로 적용하였지만, 중앙해양안전심판원은 항로지정방식의 항법을 우선 적용하였다. 이에 따라 양 기관에 의한 원인제공비율은 서로 달랐다. 필자는 본 논문에서 이에 대하여 연구하여 국제해상충돌예방규칙 제10조 제1항에 의거하여 항로지정방식이 우선 적용되고 횡단항법이 추가적으로 적용된다는 점을 밝히고 있다.

목적 : 본 연구는 운전시뮬레이터를 활용하여 운전면허가 없는 자, 초보 운전자, 2년 이상 경험이 있는 운전자의 운전수행능력을 비교 분석하고, 최근 도입되고 있는 운전시뮬레이터를 통한 평가의 효용성을 확인하고자 한다. 연구방법 : 본 연구는 신체에 이상이 없고 오른손이 우세손인 정상 성인 60명을 대상으로 진행하였다. 운전수행능력을 확인하기 위한 도구로는 운전시뮬레이터(STISIM Drive™ M400 driving almulator)를 이용하였으며 운전수행 후 결과로 제시되는 세 가지 차선유지(차선중심유지, 중앙선 침범, 외측차도침범) 항목에 대한 자료를 기초로 하여 대상자의 운전수행능력 차이를 비교하였다. 운전수행과정은 운전면허가 없는 자(n=20), 초보 운전자(n=20), 2년 이상 경험이 있는 운전자(n=20)로 그룹을 나누어 진행하였으며 시뮬레이터에 내장되어 있는 다양한 시나리오 중 복잡한 도시환경을 사실적으로 묘사한 시나리오(complex city environment)를 이용하여 약 20분 동안 운전과제를 수행하도록 지시하였다. 결과 : 운전면허가 없는 그룹은 초보 운전자 및 2년 이상 경험이 있는 운전자 그룹과 비교했을 때 세 가지 차선유지 항목 모두에서 유의한 차이를 확인할 수 있었다(p<.05). 또한 초보 운전자 그룹의 경우 2년 이상 경험이 있는 운전자 그룹과 비교했을 때 차선중심유지 및 중앙선침범 항목에서는 유의한 차이가 없었던(p>.05) 반면 외측차도침범 항목에서는 유의한 차이를 확인할 수 있었다(p<.05). 결론 : 본 연구결과 사실적인 운전경험은 시뮬레이터의 운전 시나리오 수행능력에 유의한 차이를 보여주는 것으로 확인되었다. 본 연구결과를 통해 운전시뮬레이터는 운전능력에 문제를 갖고 있는 대상자에게 적용하는데 부분적 효용성을 갖고 있다고 기대할 수 있겠다.

PURPOSES : Under the capacity conditions with balanced approach flows, roundabouts give less delay than existing signalized intersections; however, flows over 450 vehicles/hour/lane with unbalanced approach flow conditions, roundabouts efficiency drops due to the short time difference between the critical gap and the follow-up headway. The purpose of this study is developing a roundabout Signal Metering operation method by considering approach lanes degree of saturation. METHODS : A four-way-approach with one-lane roundabout is selected to compare the Signal Metering performance for the case of 16 different unbalanced flow conditions. Based on these traffic conditions, the performance is evaluated for 64 different cases of Signal Metering combinations by using SIDRA software. A degree of saturation(V/C ratio) sum for two adjoined approaches is used for the performance index of choosing Metered Approach and Controlling Approach. RESULTS : When the V/C ratio sum is 0.29~0.81 and Metered Approach flow is less than Controlling Approach flow, the average delay saving per vehicle is about 7 seconds; however, after this rage the delay saving decreases gradually until the V/C ratio sum reaches around 1.0. The range of V/C ratio sum 0.93~1.09 provides average delay saving per vehicle about 3 seconds. In case of V/C ratio sum is grater than 1.0 and the flows of Metered Approach is grater than Controlling Approach, the average delay per vehicle increases 3~11 times respectively. CONCLUSIONS : As expected, the Signal Metering provides substantial improvements in delay saving for the case of V/C ratio sum is 0.3~1.0 under the traffic flow conditions of Metered Approach is less than Controlling Approach.

PURPOSES: The purpose of this paper is to estimate expected effects on traffic operational and economic aspects of 2+1 roads application in Korea. METHODS : Micro simulation study using VISSIM 5.0 was used to analyze the operation efficiency of 2+1 roads compared to two-lane highways and four-lane highways. Some scenarios for various traffic volumes were set up in order to analyze the effect of 2+1 roads under various traffic situations. Also imaginary road networks were set up for each type of roads. The MOEs to measure the operation efficiency were selected with average travel speed and delay. For analyzing economic effect of 2+1 roads, construction cost of a specific imaginary 2+1 road was compared to construction cost of a four-lane highway with same conditions. RESULTS: The results of study show that a 2+1 road is more effective with 19 percents higher average travel speed and 39 percents lower average delay than a two-lane highway. In the economic analysis, construction costs to construct a 2+1 road are saved as approximately 26.4~40.7 percents when compared to construction of four-lane highway. CONCLUSIONS: It can be concluded that 2+1 roads can improve the traffic operational level of service for two-lane highways and 2+1 roads can be applied as an effective design alternative for higher-volume two-lane highways in Korea.