PURPOSES : Arterial work zones, particularly at signalized intersections, have several characteristics and effects different from freeways. This paper presents three significant work zone effects on signalized intersections: (1) saturation headway change (saturation flow rate change), (2) green time (g/C ratio) change, and (3) progression speed degradation impacts on bandwidth performance. METHODS : Both saturation flow rate reduction and g/C reduction were selected as the work zone impact variables for a signalized intersection, while bandwidth capacity reduction was chosen to measure the impact of work zones on arterials. The authors established a statistical model and normalized g/C table to estimate saturation headways and the g/C ratio at signalized intersection work zones based on the work intensity, pavement condition, ledge presence, turn percentages from shared lanes, and number of closed exclusive turn lanes. In addition, the dynamic bandwidth capacity and bandwidth solution space change based on the progression speed were introduced in this study. RESULTS : A normalized g/C ratio distribution was developed to estimate both the non-work zone and work zone g/C ratios under different work zone configurations. The results of the estimated work zone capacity using the work zone saturation headway model and the g/C ratio distribution showed that the estimated capacity reduction ranged from 32.78%~2.93%. In addition, arterial dynamic bandwidth and its capacity were both critically influenced by the progression speed. CONCLUSIONS : The proposed model and method will help practitioners understand the factors that cause a decrease in the saturation flow rate and g/C and influence progression quality on the urban arterial street due to work zones. Moreover, the proposed model and method can guide the calibration of simulation tools to properly represent the resulting capacity effects of work zones on arterial streets.

온도, pH, 빛 및 힘 등의 외부 자극에 반응하여 그 구조나 물리 화학적 특성이 변화 가능한 자극 감응형 하이드로젤에 대한 연구가 활발하게 진행되고 있다. 본 연구에서는 응력 감응형 분자인 스피로 피란을 사용하여 응력 및 pH 감응형 하이드로젤을 제조하였다. 먼저, 폴리에틸렌 다이아크릴레이트 (PEGDA)를 스피로피란 분자 양 끝에 접목시켜, 수용액에 쉽게 용해될 뿐만 아니라 하이드로젤 가교제 역할이 가능한 아령모양(PEG-spiropyran-PEG)의 SP-PEGDA 분자를 합성하였다. 이렇게 합성한 SP-PEGDA로 가교된 하이드로젤은 팽윤에 의해 발생하는 내부 응력에 의해 노란색의 스피로피란(SP) 분자를 보라색의 메로사인(MC) 형태로 변환시켰다. 또한 pH에 따라 양성화된 메로사인(MCH) 형태로 변환 하여 팽윤과 수축을 시각화 하였다.

PURPOSES : This study defines travel time reliability as a concept that explains the change in travel time that passengers can hardly predict and calculates the value of travel time reliability based on travel objectives. METHODS : Because the reliability of passage time is difficult to estimate from actual passenger data, standard quantification measures have not been established despite various interests. In this study, the reliability of transit time was defined as the expense that passengers did not recognize in advance, such as an accidental delay caused by unforeseen circumstances. For analysis based on the individual behavior of users, the data were constructed using the optional experiment method (marginal rate of substitution method) of the stated preference survey, which has the advantage of controlling the correlation between attribute variables and maintaining the independence of the data of the study. RESULTS : Consequently, the reliability value of travel time in mandatory-purposed traffic was almost identical to the value of travel time, and the reliability value of travel time in return and shopping/leisure, which is not mandatory during non-business-purpose traffic, is lower than the value of travel time. Comparing and analyzing with existing studies on estimating the reliability value of transit time, both work/ non-work purposes are in line with the overall research results. CONCLUSIONS : Estimating the reliability value of transit time for each purpose of passage was the first attempt, and it is meaningful to suggest a direction for quantifying and applying the reliability value of transit time along with the passage time value of this study.