• 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.

• 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.

• Journal of the Korean Society of Safety
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• v.29 no.5
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• pp.154-159
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• 2014

This study deals with the pedestrian accidents of intersections in case of Cheongju. The objective is to develop the pedestrian accident models using Tobit regression model. In pursuing the above, the pedestrian accident data from 2007 to 2011 were collected from TAAS data set of Road Traffic Authority. To analyze the accident, Poisson, negative binomial and Tobit regression models were utilized in this study. The dependent variable were the number of accident by intersection. Independent variables are traffic volume, intersection geometric structure and the transportation facility. The main results were as follows. First, Tobit model was judged to be more appropriate model than other models. Also, these models were analyzed to be statistically significant. Second, such the main variables related to accidents as traffic volume, pedestrian volume, number of traffic island, crossing length and the pedestrian countdown signal systems were adopted in the above model.

• Journal of the Korean Society of Safety
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• v.32 no.5
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• pp.135-140
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• 2017

This study deals with the safety of roundabout. The purpose of this study is to analyze the factors affecting the pedestrian accidents of roundabout near schools. In pursuing the above, this study gives particular attentions to comparatively analyzing the pedestrian accident by number of entry and circulatory lane. The traffic accident data from 2013 to 2015 are collected from TAAS data set of Road Traffic Authority. To develop the pedestrian accident model, the Poisson and negative binomial models has been utilized in this study. Such the dependent variable as the number of pedestrian accidents and the 24 independent variables as geometry, traffic volume and others are used. The main results are as follows. First, 3 Poisson and 2 negative binomial models(${\rho}^2$ of 0.153~0.426) which are all statistically significant are developed. Second, the common variable of models based on the number of circulatory roadway lane is analyzed to be the entry lane width and that of the number of entry lane is evaluated to be the design speed. Also specific variables are evaluated to splitter island, roundabout sign, number of approach road, bus stop and elementary school. Finally, the design speed might be expected to decrease the number of pedestrian accidents near schools.

• Journal of Korean Society of Transportation
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• v.35 no.4
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• pp.321-331
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• 2017

The objective of this study is to analyze the factors affecting the pedestrian accidents of roundabout near schools. To this end, this study has focus on the comparative analysis of pedestrian accidents across different school areas. The traffic accident data from 2007 to 2014 are collected from TAAS data set of Road Traffic Authority. To develop the pedestrian accident rate model, the linear regression model has been utilized in this study. 28 explanatory variables such as geometry and traffic volume factors are used. The main results are summarized as follows. First, the null hypotheses that the number of pedestrian accidents are the same are rejected. Second, 5 multiple linear regression accident models with higher statistical significance (adjusted $R^2$ of 0.651~0.788) have been developed. Third, while the common variables of 3 models (model I~III) related to school location are evaluated to be the pedestrian island, crosswalk, types of roundabout, elementary school and bus stop. Fourth, while the common variable of 3 models (model III~V) related to near school area or not is evaluated to be pedestrian island, type of roundabout, sidewalk, elementary school, speed hump, speed limit sign and number of entry lane. As a result, the installation of pedestrian islands and crosswalk might be expected to decrease the number of pedestrian accidents near schools.

• 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.

• The Journal of the Korea Contents Association
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• v.15 no.4
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• pp.197-207
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• 2015

In this research, Check the problems through analysis of traffic accidents while the elderly walking. Propose a way to reduce elderly traffic accidents. Therefore, analyzing the characteristics(by time and place etc) in order to reduce the traffic accident in the elderly pedestrian. Proposed the following Policy alternatives. First, Build a pedestrian safety island on the center of the road. Secondly, Should install the pedestrian crossing signal facilities which show the spare time and the guard rail to prevent crosswalk. Third, Should expend the installation area of pedestrian-operating traffic signal. Fourth, the night lighting facilities shall be installed nearby Crosswalk. Finally, Should appoint the elderly care area. Measures presented in this study, I hope they can be the basic data for the elderly in traffic safety policies for the elderly in accordance with the advent of aging society.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.13 no.6
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• pp.77-87
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• 2014

It has reported that a median bus-stop island on an exclusive median bus lane (EMBL) has shortened a crossing distance unit, encouraged a pedestrian's illegal crossing, and increased the number of accidents in the area. This study presents (1) the analysis of inappropriate pedestrian crossing patterns collected on exclusive median bus corridors and (2) the estimated performance of safety barriers restraining the occurrence of those. Total 19,649 pedestrian crossing data collected at the 'Sookmyung-university' median bus-stop, and the inappropriate pedestrian crossing patterns among those were grouped in terms of time and space violations. Physical safety barriers restraining illegal pedestrian crossings were considered as an alternative, and its performance in safety was quantified through microscopic simulation with conflict analyses by using surrogate safety assessment model. The findings suggest the number of conflicts reduced be 24.9 percentages compared to the one of the present condition when the physical safety barriers are placed at each of the eight ends of the EMBL pedestrian crossing.

• 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.

• International Journal of High-Rise Buildings
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• v.11 no.3
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• pp.145-156
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• 2022

Application examples of computational fluid dynamics (CFD) in the planning stage of high-rise buildings are introduced. First, we introduce examples of applications in the environmental field. The pedestrian wind environment was one of the earliest practical examples of CFD. CFD was also employed to validate the heat island mitigation measures proposed as part of the new construction plan. Second, application examples of wind-force evaluations are introduced. Prediction examples are presented for the peak wind pressure around a complex-shaped building and the wind force evaluation for a base-isolated building. The results prove that the results of the proper execution of CFD are equivalent to those of the wind tunnel experiment. As examples of CFD applications of other issues related to high-rise building planning, we introduce snow accretion on outer walls and high-temperature exhaust from emergency generators. Finally, the future prospects for the use of CFD are discussed.