• Journal of Korean Society of Transportation
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• v.14 no.3
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• pp.61-73
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• 1996

The objective of this paper is to estimate the PCE(Passenger Car Equivalents) of various vehicle types on expressway work zones. Headway samples of 5,359 vehicles were collected in 6 work zones in the Kyungbu Expressway between September and November of 1995. Average headways of 8 vehicle types based on the vehicle classification method of the Department of Construction and Transportation were calculated. A statistical test of effects of the types of the preceding vehicles were performed for the average headways between a vehicle type preceded by other vehicle types. The results show that the effects of the type of preceding vehicles are significant (exceeded 5% and 10% significance levels) and the PCEs of heavy vehicles on expressway work zones are higher than that of basic expressway section. Therefore, different adjustment factors should be applied for heavy vehicles in estimating saturation flow rates of expressway work zones. The study also derives an equation to determine PCEs of these vehicle types.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.14 no.1
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• pp.13-21
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• 2015

This study focuses on operational analysis of 2 types of intersection shared lanes. First, the analysis showed that a through & right-turn shared lane is always less used than the adjacent through-only lanes and as a result, operational efficiency deteriorates. To improve the efficiency fine-tuning in signal timing optimization using lane-by-lane traffic volume data is required. Further improvement can be achieved by guiding drivers to equally use the shared lane. For left-turn & U-turn shared lanes, it was found that saturation flow rate is affected by interference between U-turn and conflicting right-turn movements. However, since such interference does not occur in every cycle, a statistical model must be established to develop realistic adjustment factor for saturation flow rate of the shared lane.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.5
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• pp.1111-1121
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• 2015

Roundabouts face a congestion problem when there are unbalanced traffic conditions, especially during peak times. The congestion at roundabouts results in long delay times and low level of service. Some research has addressed congestion problems of the metering roundabout, however, few studies have focused on the congestion issues of the double signals metering roundabout. This research bridges this gap through analyzing the congestion issues of the Old Belair double signals roundabout in Adelaide. The research proposes a new analysis method based on a four-nodes intersection in order for double signals roundabout analysis to be carried out as follows: firstly, at the modeling stage, a connection of four individual intersections, adjustment of lane geometry, input of directional traffic volumes, priority and phase time set up are proposed. Secondly, for calibration, PFF, critical gap, follow-up headway and extra bunching values have been applied. The results from the analysis show that the new method is able to analyze the delay time, level of service, degree of saturation and allow for further analysis.

• Journal of Korean Port Research
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• v.13 no.1
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• pp.87-100
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• 1999

This study was focused on analyzing the headway of various types of trailer in Pusan city with the high heavy vehicle rate. Then Passenger Car Equivalent(PCE) was calibrated in order to identify the impact of trailers in the traffic flow at the signalized intersections. To fulfill this goal types of trailer were classified into five categories such as full trailer semi-trailer unloaded semi-trailer semi-trailer loaded with 20ft container and semi-trailer loaded with 40ft container and Passenger Car Equivalents were identified. the Results are as follows: 1) The PCE’s were 2.64, 1.51, 2.09, 2.16 and 2.23 respectively. 2) The saturation flow rate on the signalized intersection was lower than that on the multi-lane highway in the big city of Korea. 3) The start-up delay on the thru lane was similar to the average value in our country but the start-up delay on the left-turn lane was longer than the average value in our country by the impact of container Vehicles.

• Journal of Korean Society of Transportation
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• v.22 no.1 s.72
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• pp.73-82
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• 2004

신호 교차로에서 포화차두시간에 영향을 미치는 영향인자는 도로조건, 교통조건, 환경조건으로 분류된다. 이러한 요인들의 복합적인 관계가 포화차두시간에 영향을 미친다. 현재 포화교통류율은 이상적인 조건일 때의 포화차두시간을 산출하고, 이를 이용해서 기본 포화교통류율을 구하고, 여기에 좌 우회전, 차로폭, 경사, 중차량 보정계수을 고려함으로써 특정 차로군의 포화교통류율을 산정하고 있다. 포화차두시간에 영향을 미치는 인자들 중에서 정량적으로 나타내기 어려운 인자 즉, 퍼지적 성격을 가진 인자들은 고려하지 않고 있다. 따라서 본 연구에서는 퍼지 근사추론 방법을 이용하여 정성적 인자의 영향을 고려한 모형을 구축하였다. 모형의 입력자료는 강우조건과 주변밝기의 정도, 중차량 구성비의 언어적 표현를 사용하였다. 이러한 변수들에 대하여 설문조사를 통해서 퍼지집합의 멤버쉽함수를 설정하였으며. 이에 기초하여 교차로에서 각 조건별로 포화차두시간을 관측하였다. 이러한 현장 관측치를 바탕으로 퍼지 제어규칙을 설정하고 모형을 구축하였다. 모형의 평가는 추론치와 실측치를 비교함으로써 이루어 졌으며, 결정계수인 $R^2$와 평균절대오차(MAE)와 평균제곱오차(MSE)를 사용하여 분석한 결과 본 모형의 설명력이 높은 것으로 평가되었다. 본 연구의 과정에서 강우에 의한 교통용량 감소는 중차량 구성비가 클수록 주변밝기의 정도가 나쁠수록 더욱 큰 것으로 나타났으며 그 감소율은 5.3%에서 21.8%에 이르는 넓은 범위의 값을 보였고. 주변밝기 정도에 따른 교통용량 감소는 4.7$\sim$7.5% 수준으로 나타났다.