Swedish national road and transport research institute

A clustering regression approach: A comprehensive injury severity analysis of pedestrian–vehicle crashes in New York, US and Montreal, Canada

Visualization and analysis of mapping knowledge domain of road safety studies

Exploring the determinants of pedestrian–vehicle crash severity in New York City

Understanding the underlying relationship between pedestrian injury severity outcomes and factors leading to more severe injuries is very important in dealing with the problem of pedestrian safety. To investigate injury severity outcomes, many previous works relied on statistical regression models. There has also been some interest for data mining techniques, in particular for clustering techniques which segment the data into more homogeneous subsets. This research combines these two approaches (data mining and statistical regression methods) to identify the main contributing factors associated with the levels of pedestrian injury severity outcomes. This work relies on the analysis of two unique pedestrian injury severity datasets from the City of New York, US (2002-2006) and the City of Montreal, Canada (2003-2006). General injury severity models were estimated for the whole datasets and for sub-populations obtained through clustering analysis. This paper shows how the segmentation of the accident datasets help to better understand the complex relationship between the injury severity outcomes and the contributing geometric, built environment and socio-demographic factors. While using the same methodology for the two datasets, different techniques were tested. For instance, for New York, latent class with ordered probit method provides the best results. However, for Montreal, the K-means with multinomial logit model is identified as the most appropriate technique. The results show the power of using clustering with regression to provide a complementary and more detailed analysis. Among other results, it was found that pedestrian age, location at intersection, actions prior to accident, driver age, vehicle type, vehicle movement, driver alcohol involvement and lighting conditions have an influence on the likelihood of a fatal crash. Moreover, several features within the built environment are shown to have an effect. Finally, the research provides recommendations for policy makers, traffic engineers, and law enforcement to reduce the severity of pedestrian-vehicle collisions.

A Clustering Regression Approach: A Comprehensive Injury Severity Analysis of Pedestrian-Vehicle Crashes in New York, U.S. and Montreal, Canada

A Multinomial Logit Model of Pedestrian-Vehicle Crash Severity

This paper presents a sidewalk pavement width design method for making more pedestrian friendly and walk-inspiring sidewalk pavements in the urban area. Instead of using the current sidewalk pavement width design standard that usually leads to having minimum values, this research investigated pedestrians’ preferences on the levels of service, surveyed actual foot path trajectories in the sidewalk pavements, and observed pedestrian movement characteristics in the streets. Further, these investigation results were summarized to propose a new urban sidewalk pavement width determination procedure. The proposed procedure was applied in a case study site in Seoul, and its application resulted in a much higher pedestrian level of service. It is anticipated that the proposed method should be of service in both planning and retrofitting urban streets to make more pedestrian sensitive street designs.

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Determining the sidewalk pavement width by using pedestrian discomfort levels and movement characteristics

This study proposed a behavioral theory-based approach to better assess pedestrian levels of service for sidewalks, using the concepts of personal space and pedestrian evasive movements. Data from pedestrian interviews and video recordings at 28 commercial, residential, and leisure locations were used to analyze the effects of pedestrian movements on pedestrian perceived levels of service. With these results, a new measure of pedestrian level of service was developed. With the use of a separate validation sample, the revised levels of service obtained were found to be more consistent with the pedestrian perceived levels than the levels prescribed by the Korean Highway Capacity Manual. Hence, this research recommended the use of the revised measures for pedestrian level of service in the design and evaluation of pedestrian facilities. We also found that pedestrian evasive movements on sidewalks could better explain pedestrians' perception of the levels of service for a given facility. Moreover, pedestrian evasive movements were found to be sensitive to the width of the sidewalk and pedestrian volume. Copyright © 2013 John Wiley & Sons, Ltd. Language: en

Personal space, evasive movement and pedestrian level of service

This paper provides study results of the pedestrian level of service (LOS) within the roadside walking environments The comfort needs of pedestrians and the multimodal LOS are the main issues of the study The approach applied in the research includes a literature review, a pedestrian intercept survey, and a multiple regression analysis Major findings include: (1) current measure of effectiveness for determining pedestrian LOS in the Korean Highway Capacity Manual should be replaced with a more realistic measure of effectiveness, such as the level of pedestrian satisfaction, (2) pedestrian perception within roadside walking environments was successfully captured in a model developed in this study, and (3) the impact of adding automobile-related variables to explanatory variables was statistically significant Cross-section design elements affecting the perception of pedestrian LOS were also identified It is hoped that this research will provide an increased understanding for pedestrian-friendly strateg

Roadside walking environments and major factors affecting pedestrian level of service

The study investigates data concerning crashes at roundabouts in order to identify the major factors influencing such events in South Korea. In this investigation, three stages of research tasks were carried out. First, crashes which occurred at South Korean roundabouts were categorized and subsequently compared with international cases. Second, field surveys were conducted in order to investigate how vehicle speeds influence the occurrence of accidents. Third, a statistical analysis was performed in order to investigate the correlation between roundabout geometry and crash occurrences and to reveal major geometric elements of roundabout safety. It was revealed in the study that most vehicles slow down substantially around roundabouts and recover their speed after the roundabouts. Based on the statistical analysis, it was found that negative binomial distribution would give a better performance. In addition, in contrast to cases in the US, the final selection of the independent variables includes as follows: the number of approaches, the number of entering lanes, the entry width, the flare width, the number of circulating lanes and the circulating lane width. Finally, the study provided a model with which to capture the relationship between geometric design elements and the occurrence of crashes at roundabouts. It is anticipated that this model will be applied by engineers to better predict crash occurrences at roundabouts.

Jaisung Choi

Papers

A Multinomial Logit Model of Pedestrian-Vehicle Crash Severity

Determining the sidewalk pavement width by using pedestrian discomfort levels and movement characteristics

Personal space, evasive movement and pedestrian level of service

Roadside walking environments and major factors affecting pedestrian level of service

Safety Analysis of Roundabout Designs based on Geometric and Speed Characteristics