Shenjun Yao

Measures of activity-based pedestrian exposure to the risk of vehicle-pedestrian collisions: Space-time path vs. potential path tree methods

Research on the extent to which pedestrians are exposed to road collision risk is important to the improvement of pedestrian safety. As precise geographical information is often difficult and costly to collect, this study proposes a potential path tree method derived from time geography concepts in measuring pedestrian exposure. With negative binomial regression (NBR) and geographically weighted Poisson regression (GWPR) models, the proposed probabilistic two-anchor-point potential path tree (PPT) approach (including the equal and weighted PPT methods) are compared with the deterministic space-time path (STP) method. The results indicate that both STP and PPT methods are useful tools in measuring pedestrian exposure. While the STP method can save much time, the PPT methods outperform the STP method in explaining the underlying vehicle-pedestrian collision pattern. Further research efforts are needed to investigate the influence of walking speed and route choice.

The Rural-Urban Divide in Road Safety: The Case of China

Mainland China accounted for about 7% of the global road fatalities in 2008. Road crashes happening on Chinese roads were deadly. On average, one person died in every four reported traffic crashes. Despite the scarcity of data, substantial rural-urban differences were found. In the rural areas, higher-order Highways, roads with no lighting and some heavy vehicles warrant particular attention from road safety administrations. In the 2000s, the average number of road fatalities per 100 crashes on Expressways quadrupled. Furthermore, the rural-urban divide was not limited to inner provinces only but was found in a large part of the country. By 2008, nearly 70% of the provincial units were having larger shares of rural population. In the long term, only a national road safety strategy will provide the necessary holistic framework for addressing the road safety problems in China systematically.

Traffic collisions in space: four decades of advancement in applied GIS

Abstract Traffic collision analysis is essential for reducing traffic injuries. While most traditional approaches focus on the time dimension of traffic collisions, the recent past has witnessed a growing awareness of the spatial dimension in a geographical context. In this paper, 70 studies on the application of GIS to the spatial analysis of traffic collisions are reviewed. The purpose of the paper is to provide a systematic analysis of the major advancements in applied GIS for studying traffic collisions in space since the mid-1970s.

Safety in numbers for cyclists beyond national-level and city-level data: a study on the non-linearity of risk within the city of Hong Kong

Objective This paper examines the relationship between bicycle collisions and the amount of cycling at the local level. Most previous research has focused on national and city comparisons, little is known about differences within a city (the mesoscale). Methods This study mainly used three types of data sets relating to bicycle collisions, use of bicycles and local neighbourhood characteristics in Hong Kong. In particular, bicycle usage, measured as bicycle-kilometres travelled, was estimated from travel surveys following the activity-based approach. Negative binomial regression models were established to model the relationship between the amount of cycling and the occurrence of bicycle collisions at the spatial scale of the Tertiary Planning Unit, which is the smallest planning unit of the city. Results The numbers of bicycle collisions went up with the increasing use of bicycles, but the increase in the number of collisions in a given community was less than a linear proportion of the bicycle flow. When other local neighbourhood variables are controlled, the amount of cycling is a statistically significant variable in accounting for the number of collisions. Conclusions Even in a highly motorised city where bicycles are a minor transport mode, cyclists are less likely to be involved in road collisions in communities with higher cycling volume. Since cycling activities are likely to vary within a city, a more local-based approach in promoting cycling is needed. In particular, the higher safety risks in neighbourhoods of low bicycle usage, especially at an initial stage of promoting cycling, need to be addressed properly.

Geographical Information Systems

Unlike contagious diseases such as influenza, injury is not spatially contagious. Yet, its occurrence is clearly influenced by locational factors. Reducing injury has to do with understanding the underlying spatial relationships beyond simple mapping. With geographic information systems (GIS) and other information technologies, researchers can now integrate large quantities of both spatial and nonspatial data and examine underlying relationships through hypothesis testing. In this chapter, we first introduce different types of GIS-based spatial analysis methods for crash analysis and prevention. Then, we introduce a GIS-based network analysis approach for the identification of hazardous road locations. Finally, we conclude by suggesting ways forward for better utilizing the spatial data and spatial modeling capacities to reduce traffic injury.