It is well known that weather conditions are closely related with the number and severity of traffic accidents. At present, installation of safety countermeasures including systems is common approach to reduce the damage of traffic accidents at expressways. In this study, the differences of causation factors to influence traffic accidents considering road alignment characteristics and weather conditions. In order to identify the relationship between road and weather conditions, discriminant analysis has been performed with 500 traffic accident data at expressways. Weather conditions are divided into several categories such as snow, sunny, rain, fog, and cloud. Also, road conditions such as types of pavements, grades are analyzed. As the results, major impacting road conditions to traffic accidents are concrete pavement and 3% or more down grades. In these road conditions, visible distance will be reduced and actual braking distances will be increased. This study shows that the expressway sections under concrete pavement and down grades should be more cautious than other sections. It also shows that fog condition is the mose dangerous situation in terms of traffic accidents.
Abstract Objective The aim of this study was to investigate changes in objective sleep quality with hormone therapy (HT) in women with late menopausal transition. Methods Healthy midlife women with sleep difficulty who received HT were included. Those undergoing late menopausal transition were screened. Sleep patterns and self-reported questionnaires were collected before and 10 weeks after starting HT. Results Ten women who met the criteria (age, 50.1 ± 2.8 years) showed higher sleep efficiency and shorter wakefulness after sleep onset (WASO) 10 weeks after starting HT. However, no significant change was found in objective sleep quality after adjustment for multiple comparisons: sleep efficiency, 84.2 ± 7.7 versus 88.2% ± 4.7%, P = 0.037, adjusted P = 0.259; WASO, 59.0 ± 27.2 minutes versus 41.4 ± 17.4 minutes, P = 0.020, adjusted P = 0.140; average duration per awakening, 2.9 ± 1.0 minutes versus 2.2 ± 0.5 minutes, P = 0.033, adjusted P = 0.231. A better score of subjective sleep quality in the Pittsburgh Sleep Quality Index was observed 10 weeks after starting HT (2.0 ± 0.0 vs 1.2 ± 0.4, P = 0.006, adjusted P = 0.042), but sensitivity analysis did not show consistent results after adjustment for multiple comparisons (2.0 ± 0.0 vs 1.1 ± 0.4, P = 0.020, adjusted P = 0.140). Total scores of the Insomnia Severity Index and Menopause Rating Scale were better 10 weeks after starting HT (Insomnia Severity Index, 14.7 ± 3.0 vs 9.1 ± 3.8, P = 0.010; Menopause Rating Scale, 29.0 ± 5.2 vs 21.6 ± 3.0, P = 0.009) with consistent results in sensitivity analyses. There was no difference in the Epworth Sleepiness Scale before and after HT (7.2 ± 1.7 vs 8.6 ± 4.5, P = 0.309). The change in each objective sleep quality variable before and after HT showed strong positive or negative correlations with the change in only a few items in subjective sleep quality. Conclusion Women in the late menopausal transition period showed higher sleep efficiency and shorter WASO after HT; however, multiple comparisons showed no statistically significant difference in objective sleep quality between before and after HT.
현재 서울시는 대중교통 활성화 정책에 따라 버스전용차로제도를 실시하고 있다. 과거 가로변버스전용차로 설치를 시작으로 현재에는 중앙버스전용차로 설치구간도 증가하고 있다. 본 연구의 목적은 이 중앙버스전용차로와 가로변버스전용차로에서 버스사고에 영향을 미치는 요인을 분석하는데 있다. 분석방법으로 교통사고가 확률적으로 극히 드물게 일어난다는 점을 생각하여 포아송 회귀모형과 음이항 회귀모형을 선택하였으며, 과산포 존재여부에 따라 음이항 회귀모형으로 최종모형을 정립하였다. 중앙버스전용차로구간은 버스노선수, 중앙차로 진출입 유형수, 중앙차로 정지선 후퇴유무, 중앙차로 정지선과 횡단보도 이격거리, 교통량, 가변차로 정류장 정차노선수 6개의 변수에서 버스사고에 유의한 영향을 미치는 것으로 나타났다. 가로변버스전용 차로구간은 우회전 버스노선수, 상습 불법주정차 유무, 보행신호시간, 토지이용형태 4개의 변수에서 버스사고에 유의한 영향을 미치는 것으로 나타났다. At present, Seoul City is putting the bus exclusive lane system into practice according to mass transit revitalization policy. Starting with the installation of roadside bus exclusive lane in the past, at present, even the road sections for central- lane bus exclusive lane system are on the increase. The purpose of this research is to analyze the factors giving impacts on bus accident on central bus exclusive lane and roadside bus exclusive lane. In case of the central bus exclusive lane, the 6 variables, such as the number of bus routes, number of access & entrance to central lanes patterns, whether the stop line of central lanes retreats or not, separated distance between the stop line of central lanes and crosswalks, traffic volume, and number of bus routes stopping at bus stops on reversible lanes, were found to have a significant influence on bus accidents. In case of roadside bus exclusive lane sections, the four variables such as the number of right-turn bus routes, whether to be chronic illegal parking & stopping, time for the walk signal, and forms of land use, etc. were found to have a significant influence on bus accident.
PURPOSES : The causes of traffic accidents can be classified into the factors of highway users, vehicles, and driving environments. Traffic accidents result from the deficiency in single or combination of these three factors. The objective of this study is to define the "potentially hazardous sections of highway" in terms of traffic safety considering these three factors. METHODS : The test drivers performed repeated driving on these highway sections. The drivers and passengers recorded the sections on which the driving was uncomfortable, and the speeds on the sections excluding the uncomfortable sections were used for the development of the model. RESULTS : The model is composed of three sub-models for each of the horizontal curve, tangent, and the section where the curve starts/ends. The safe driving behavior coefficients by the horizontal curvature were derived by comparing the maximum operating speeds at which the vehicle may slide or deviate and the speeds at which the drivers feel comfort. The safety speeds on tangent were derived by the length of tangent section considering the driver's desired speeds under the traffic condition on which the drivers hardly influenced by the other vehicles. For the sections where the curve starts/ends, the driving behaviors were classified by the distances between the curves, and the safe acceleration/deceleration speeds were derived on which the drivers enter/exit the curve sections safely. CONCLUSIONS : Safety speed could then be regarded that the model suggested in this study may be useful to define the potentially hazardous highway section and contribute the improvement of highway safety.
The purpose of advanced traffic information system(ATIS) is to help drivers save time and energy in getting to their destinations by providing traffic information through variable message sign(VMS), internet, traffic broadcasting and mobile phones. ATIS does not just provide drivers with benefits in terms of time and energy, but it provides them with psychological benefit as well, i.e., the drivers can relieve their anxiety by getting provided with traffic information. In this study, the efficiency of traffic information system is evaluated and degree of satisfaction of drivers with the system is analyzed by building satisfaction models of various media of traffic information. Each medium has different factors for satisfaction and each factor has different degree of influence, but in general, the efficiency of traffic information in helping drivers choose routes and in providing drivers with peace of mind is considered to have the highest influence on satisfaction of drivers with the system.
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