• Journal of Korean Society of Transportation
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• v.14 no.3
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• pp.75-90
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• 1996

The objective of study is to examine relationship between traffic flow characteristics of two lane entrance terminal and acceleration length, and to suggest the acceleration length by level of service. The relationship between the speed ratio and the distance from the ramp appeared to be a quadratic concave from. In the case of two lane entrance ramp, the acceleration length is suggested as 1.4~2.0 times longer than the acceleration length of one lane entrance ramp. It is also recommended that acceleration length for two lane entrance ramp should be designed according to the level of service at the right most lane (level of service A : 1.4 B : 1.6 C : 1.8 D : 2.0 times of the one lane entrance ramp acceleration length) on freeway.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.6
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• pp.54-66
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• 2018

In this study, vehicle speeds at acceleration and deceleration lanes of rest areas for drowsy drivers were investigated to analyze effects of acceleration and deceleration lane lengths, grades and curve radius. In addition, we used VISSM to analyze proper lengths of rest area's acceleration and deceleration lanes. Several VISSIM scenarios with different lengths of acceleration and deceleration lane were constructed. Through VISSIM simulation, we collected individual vehicle speed data to analyze speed changes by different lengths of acceleration and deceleration lanes. As a result of the vehicle speed change investigation, grades and curve radii of the rest area affected the speed, most of all lengths of acceleration and deceleration lane showed a great effect on the vehicle speed. In the case of short lengths of acceleration and deceleration lane, speed variation among vehicles was significant. If the deceleration lane length is short, the vehicle enters a state in which the speed is not sufficiently reduced, and if the acceleration lane length is short, the vehicle enters a state in which the speed is not sufficiently accelerated showing high risks of conflicts and accidents. It is recommended that 245m length of deceleration lane and 370m length of acceleration lane should be installed at least to secure safety and manage conflicts relevantly.

• Journal of Auto-vehicle Safety Association
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• v.15 no.3
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• pp.17-26
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• 2023

This paper presents extended state feedback control based on impulse response for lane change of autonomous driving vehicle. The triple characteristic root of path tracking system and longitudinal velocity determine feedback gains. We suggest a resemblance of impulse response curve of the system and lane change trajectory of the vehicle. The root affects the duration of lane change and lateral acceleration. The effect of limited lateral acceleration and saturation of steering angle will be analyzed and discussed. Finally, simulation results will show the trajectory of lane change based on impulse response under limitation of lateral acceleration.

• Journal of Korean Society of Transportation
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• v.23 no.8 s.86
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• pp.53-66
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• 2005

This paper analyzes the effects of acceleration lane lengths on the traffic characteristics of merging areas. Two merging areas, Suwon IC and Singal JC, which have remarkably different acceleration lane length were selected as field study sites. Traffic data were collected through dividing each merging area into several subsections. Not only conventional flow, speed and density data but also a newly introduced MOE, density variation were used to analyzed the characteristics of merging area. Singal JC which has longer acceleration lane than Suwon IC showed more severe congestion, and the cause of the results was figured out.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.3
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• pp.409-415
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• 2022

The length of the acceleration lane in the area of entrance terminals is calculated based on 13 PS/ton horsepower of a cargo truck in Korea, so it is generally overestimated compared with the capacity of most vehicles traveling on an entrance ramp. Most drivers have, therefore, an indiscreet tendency to enter the main lane in all sections of an acceleration lane, which affects the traffic flow of the main lane. Because of this tendency, measures are required to minimize the impact on traffic flow of the main lane. The operating speed, rate of entrance, and traffic volume for each vehicle were investigated at the entrance terminals of the interchanges (ICs) of Yangji IC, Suseok IC, Yongin IC, and Osan IC, and the level of improvement in traffic flow was analyzed via VISSIM simulation. From the VISSIM simulation analysis, 74.0 % of the total vehicles traveled over the specified speed from the nose point where drivers would be able to recognize the traffic condition of the main carriageway, or the point at which there is a simplification of the curve section. In addition, 88.6 % of the vehicles entered the main carriageway up to 0.8 points compared with the entire length of the acceleration lane. It was subsequently found that an improvement of average speed in the main carriageway and at the entrance ramp can be achieved from 60.1 km/h to 68.5 km/h by intentionally limiting the entrance point onto the main carriageway up to 0.265 points of the entrance ramp.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.8
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• pp.112-119
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• 2004

This paper develops a computer model of a cabover type large truck for estimating the effects of the mounted method of frame on handling performance. The computer model considers two mounted methods of frame; flange mounted and web mounted. Frame is modeled by finite elements using MSC/NASTRAN in order to consider the flexibility of frame. The reliability of the developed computer model is verified by comparing the actual vehicle test results with the simulation results. The actual vehicle test is performed in a double lane change course, and lateral acceleration, yaw rate, and roll angle are measured. To estimate the effects of the mounted method of frame on handling performance, simulations are performed with the flange mounted and web mounted frame. Simulation results show that the web mounted frame＇s variations of roll angle, lateral acceleration, and yaw rate are larger than the flange mounted frame＇s variations, especially in the high test velocity and the second part of the double lane course. Also, simulation results show that the web mounted frame＇s tendencies of roll angle, lateral acceleration, and yaw rate advance the flange mounted frame＇s tendencies, especially in the high test velocity and the second part of the double lane course.

• Journal of Korean Society of Transportation
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• v.27 no.6
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• pp.109-118
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• 2009

The conventional lane changing model has been developed without acceleration or deceleration of vehicles at target lane. Thus, existing lane changing models have limitation to apply in real world. In this paper, lane changing model considered acceleration or deceleration, and calculated the safety distance between subject vehicle and adjacent vehicles for lane changing as well. Simulation was conducted to verify the validity and the efficiency of the developed lane changing model in this paper. Several scenarios were carefully examined by safety distance between subject vehicle and adjacent vehicles. In the result, it was verified that if gap between subject vehicle and adjacent vehicles is larger than safety distance, lane changing behavior between subject vehicle and adjacent vehicles avoids collision. The suggested lane changing model may be applied at the future driver assistance system and advanced safety vehicle.

• Journal of Korean Society of Transportation
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• v.20 no.6
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• pp.115-128
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• 2002

Traffic engineers have developed and implemented various microscopic simulation models to verify the traffic performance and to prevent the expected problems. The existing microscopic simulation models categorize drivers into several types to reflect various drivers' driving patterns but miss the dynamics of drivers' behavior changed based upon the traffic conditions. It was found from the field data collected from two different merging sections on an urban freeway in Seoul, Korea, that the drivers' critical gap distributions are changed based on (1) the traffic density on the adjacent lane to the acceleration lane and (2) the opportunities left to merge in terms of distance to the end of acceleration lane. It was also found from the study that the drivers' critical gap distributions follow the Normal distribution. and its mean and variance change while a vehicle progresses on an acceleration lane. This paper proposes a new gap-acceptance model developed based on a set of drivers' critical gap distributions from each segment on the acceleration lanes. Through the comparison study between the field data and the results from the simulation utilizing the proposed model, it was verified that (1) the distribution of merging points on an acceleration lane to the adjacent main lane at different density levels, (2) the size of the gap accepted for merging and (3) the speed difference between the merging vehicle and the trailing vehicle at the time of merging are statistically identical to the field data at 95% confidence level.

• Journal of Korean Society of Transportation
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• v.14 no.3
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• pp.155-172
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• 1996

This study is to analyze speed variation at merging section of successive entrance ramp and to suggest design criterion of ramp spacing at successive entrance ramp in urban area. The major findings are as follows ; (1) The relationship between the speed at merging section of successive entrance ramp and the distance from the merging point represents concave curve. (2) The 85 percentile speed(S) at outside lane (lane 1) is modeled S = 49.5 + 355.7(D/Q) - 0.94(D2/Q) + 6.78(D/AL2) where, D = Distance from merging point(m), Q = Lane 1 volume(vph) AL2 = Acceleration length at second entrance ramp(m) (3) The more traffic volume and the shorter acceleration length of the second entrance ramp, longer ramp terminal spacing is needed.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.932-937
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• 2003

In this paper, we will explain about the unmanned vehicle control and modeling for combined obstacle avoidance and lane tracking. First, obstacle avoidance is considered as one of the important technologies in the unmanned vehicle. It is consisted by two parts: the first part includes the longitudinal control system for the acceleration and deceleration and the second part is the lateral control system for the steering control. Each system uses to the obstacle avoidance during the vehicle moving. Therefore, we propose the method of vehicle control, modeling and obstacle avoidance. Second, we describe a method of lane tracking by means of vision system. It is important in the unmanned vehicle and mobile robot system. In this paper, we deal with lane tracking and image processing method and it is including lane detection method, image processing algorithm and filtering method.