• Journal of Korean Society of Transportation
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• v.28 no.2
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• pp.21-32
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• 2010

A traffic island, typical channelization facilities, is widely applied to newly road designs and black spots improvement projects as traffic safety measures. However positive effects of a traffic island for traffic safety have not been reported specifically. Accordingly this study analyzed the accidents reduction effectiveness and economics of installing traffic islands under various roadways and traffic conditions. For this purpose normality test, paired t-test and Wilcoxon signed rank test were applied to this study based on traffic accidents, roadways and traffic environments data for 3 years before and after improvement at 54 intersections. The results showed that most of traffic accidents were reduced significantly after installing traffic islands except when traffic islands were installed in outside of cities and farming regions where use efficiency is low, curve sections with poor visibility, poor alignment sections with acceleration/deceleration lanes, road sections where occurs conflicts frequently due to did not install of acceleration/deceleration lanes, and road sections where cross with single lane road.

• Journal of Korean Society of Transportation
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• v.27 no.2
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• pp.107-115
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• 2009

Traffic islands were introduced for drivers and pedestrians to use the road in a safe and orderly way and were also a specified zone between traffic lanes to divide conflicting traffic flows and to provide pedestrian refuge. However, existing research and relevant standards described its purpose and effects only but not a safety standard to decide whether the traffic island warranted. This study was to introduce a parameter which had a high relationship with accidents by analyzing road and traffic conditions and traffic accident data at urban intersections. Based on the relationship between the parameter and the traffic accidents at the intersection, a pedestrian accident probability model was made by using a logit model. In addition, the study reviewed a pedestrian accident probability corresponding to traffic volume and size of the intersection during design of the intersection and then suggested the effectiveness of the traffic island in terms of traffic safety. In conclusion, when a large-scale intersection has significant traffic volumes, a high probability of traffic island-induced pedestrian accidents appears, while in the case of small volumes, the probability is low. Targeted design and operations of a traffic islands is necessary, because its introduction itself does not enhance pedestrian safety in all cases at all intersections. This study can be a useful reference for further development to set up a scheme of the traffic islands in terms of traffic safety.

• 도로교통
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• s.98
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• pp.102-115
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• 2004

• Journal of Korean Society of Transportation
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• v.30 no.5
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• pp.23-31
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• 2012

The objective of this study is to develop the design criteria of traffic island considering pedestrian level of service (LOS). In pursuing the above, this study gives particular emphasis to suggesting the minimum design space of traffic island in order to maintain pedestrian LOS C and D, and the critical pedestrian traffic volume that reflects the intersection geometry (2 lanes per direction) through the simulation analysis. The main results are as follows. First, the spaces of 160 traffic islands, which meet the pedestrian LOS C and D and reflects the pedestrian traffic volume by signal cycle, are drawn by using a commercial simulator VISSIM. The relevant spaces of traffic island in terms of both the pedestrian LOS and the pedestrian traffic volume are evaluated to range from $3.0m^2$ to $41m^2$. Second, the critical pedestrian traffic volume for the operation of traffic island is evaluated to be 1,000-1,300 person/hour at LOS C and 1,600-1,800 person/hour at LOS D, respectively, when a cycle of 120-150 seconds were applied to a intersection with two lanes per direction.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.6
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• pp.97-107
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• 2013

On the Staggered Crosswalks, pedestrians cross the crosswalks two times. This method can reduce the cycle, the vehicle delay and the walking distance by increasing the major direction of green time. The safety of pedestrians is also effective. This study suggests the warrant of the facilities of island width and length etc. by considering the road structure and pedestrians. Also this study suggests the standard of the safety through the accident analysis of Staggered crosswalks and General Crosswalks. In the results, accident rate of the Staggered Crosswalks 18.3(100 million vehicle-km) was lower than the accident rate of the General Crosswalks 28.3(100million vehicle-km). By understanding the start point of crossing of the Staggered Crosswalks, the analysis of the location and types of accident suggests the safety zone(spare space). The setting warrants of Staggered Crosswalks are 4 lane over the road and the 2 meter over sidewalk width of island. The minimum length of the Pedestrian island was doubled compared to the crosswalks width. And the maximum length was set by considering the wait time of the pedestrians.

• Journal of Korean Society of Transportation
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• v.23 no.5 s.83
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• pp.73-81
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• 2005

Triangle-shaped island was been used for the exclusive separation between the right-turn and the through flow. However, in case that existing Triangle-Shaped Island is built at the intersection of narrow road. there are more possibilities of traffic collision trespassing into the opposite lane. Accordingly, separation of the opposite lane is required so as to prevent the intrusion of the large-sized (a heavy) vehicle into the opposite lane turning at the intersection. This study showed the comparison between intersection composed of existing Triangle-Shaped Island and the intersection with Drop Island is added. First of all, in the safety aspect, a method to decide location and shape of Drop Island considering turning trajectory of the large-sized (the heavy vehicle) is addressed. The guideline on the placement of drop island install location and method to decide form the consider heavy truck's turn trajectory in safety side. As a conclusion. we analyzed that drop island is relatively superior to existing Triangle-Shaped Island in terms of driver, ease of driving, driving pleasantness, pedestrian, widening and economic performance aspect.

• Korean Journal of Environment and Ecology
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• v.35 no.5
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• pp.569-575
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• 2021

This study analyzed the effect of forests on reducing particulate matter by investigating the particulate matter concentration and influencing factors between urban forest and traffic forest. The concentrations of particulate matter in Hongreung Experimental Forest (urban forest) and a forest (traffic forest) formed at the intersection of Cheongryangri Station in Dongdaemun-gu, Seoul were measured with the light scattering method instrument from January to November 2018. During the study period, the average PM₁₀ concentrations in the urban forest and the traffic forest were 12.5㎍/m³ and 15.7 ㎍/m³, respectively, and the average PM_2.5 concentrations were 16.6㎍/m³and 6.9 ㎍/m³, respectively. Comparing the concentration by the urban atmospheric measurement network of the Ministry of Environment and the concentration in urban forests showed that the reduction rate of PM₁₀ was 66.9±28.6% in urbanforest and 58.6±44.1% in traffic forest and that of PM_2.5 was 71.3±23.0% and 64.9±31.3%. The difference in the reduction rate of particulate matter is likely related to the size and structure of the urban forest, and the wind velocity is considered the reduction factor.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.2D
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• pp.217-225
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• 2009

The study on the left turning trajectory has not done many times in Korea. Because of this, there are a lot of intersections built without considering on turning trajectory of vehicles, in Korea, and we can see many conflicts, reduced capacity of turn, especially at small intersections. Even if left turn trajectory is designed well, it is not easy to mark exactly on the pavement according to the turn trajectory. This study suggests "drop Islands" which can be seen in Europe, and is introduced in Korea recently, to solve the problems of conflicts and reduced capacity of turning. It suggests a table of location of the stop line so that the engineers who design the intersection design appropriate left turn trajectory and marking of the stop line and turn trajectory is done more exactly. To evaluate the effect of "drop island", two intersections with and without drop island were compared on the turnning radii and location of stop line. Construction of "drop island" can increase the capacity of intersection and safety without additional land and construction expenses.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.2D
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• pp.209-215
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• 2011

Roundabout has circular traffic island in the intersection center and is kind of intersection where the automobile bypass circular traffic island. In Korea, the provisional Roundabouts Design Guidelines were published in 2004 by MLTM (Ministry of Land, Transport and Maritime Affairs). This guideline did not discussed domestic traffic circumstance. It just only introduced foreign instances and their guidelines. In addition, the recent National Competitiveness roundabouts as part of the green growth has been concentrated on the interest. In this paper, 90 degree of the 4-legged roundabout was compared with 72 degree, 45 degree, and 30 degree 5-legged roundabouts by micro simulation VISSIM. As a result of analysis, average travel time is decreased when the inscribed circle diameter become bigger the roundabout. 5-legged roundabout until 2,000 volume per hour evaluated to be similar effect at 90 degree of 4-legged roundabout.

• Magazine of the Korean Society of Agricultural Engineers
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• v.61 no.2
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• pp.62-68
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• 2019