I Made Brunner

Influence of Land Use, Population, Employment, and Economic Activity on Accidents

In this study, the relationships between land use, population, employment by sector, economic output, and motor vehicle accidents are explored. Through the use of comprehensive data from the largest county in Hawaii, the relationships are modeled in a uniform 0.1-mi2 (0.259-km2) grid structure and with various linear regression models. This method has an advantage over other approaches that have typically used unevenly sized and shaped traffic analysis zones, census tracts, or block groups. Positive, statistically significant relationships among population, job counts, economic output, and accidents are identified. After some of the general effects are sorted through, a negative binomial (NB) model is used to look at the absolute and relative effects of these factors on the number of pedestrian, bicycle, vehicle-to-vehicle, and total accidents. With a multivariate model, the different effects can be compared and the specific nature of the relationships between zonal characteristics and accidents can be id...

Use of Safety Viewgrams to Visualize Driver and Pedestrian Interactions

The purpose of this paper is to describe the development of a tool for visualizing, at a glance, the salient features of the interaction between motorists and pedestrians. Simple, yet robust and flexible, tools are needed to describe and summarize real-world roadway conditions for problem identification and to monitor the progress that has been made toward achieving safety goals. In the study described in this paper, the safety viewgram has been developed to help visualize various types of traffic safety problems. Although this particular tool has been developed by using observational data for pedestrians and drivers in Hawaii, it could be used for other types of safety studies in other locales. After the development and use of this tool are described, a number of different illustrative examples of how it might be used are provided. Although this is largely a visualization tool, efforts are under way to devise both more rigorous statistical applications and a user-friendly interface for data entry, data manipulation, and presentation of the traffic safety viewgram.

Analytic Hierarchy Process and Geographic Information Systems to Identify Optimal Transit Alignments

Honolulu, Hawaii, like other urbanized centers, is struggling to solve problems of transportation supply and demand. One proposed solution is construction of a fixed-rail transit system along the east-west corridor, to connect the western part of the county to the downtown work zones. Setting up a transit alignment that meets technical, social, economical, and environmental considerations is a challenge. This study coupled the technologies of analytic hierarchy process (AHP) and geographic information systems (GIS) to assist in the decision-making process of determining optimal transit alignment between the competing Salt Lake and Airport alignments in Honolulu. The goal of the AHP structure was to determine the location for the transit alignment: technical, social, economical, and environmental considerations are the criteria, and suitability levels are the alternatives. A uniform grid structure was developed: thematic maps related to the independent variables were converted into a 0.1-square-mile grid map. The grid data and survey results were entered into the AHP structure to produce an index of suitability that could be plotted in the GIS environment to indicate optimal alignments for the rail transit system on the basis of public preferences and technical criteria.

Entropy and Accidents

This study explored the relationships between land use entropy (the extent to which land uses are mixed, heterogeneous, and nonuniform) and motor vehicle accidents. Two aspects of entropy were considered: (a) the mix of jobs and housing and (b) the diversity of jobs in addition to the mix of jobs and housing. These measures were developed and tested with census data and geographic information system technologies combined with comprehensive police accident reports from the city and county of Honolulu, Hawaii. A grid-based approach was adopted with accident counts and negative binomial regression. Various types of accident counts were considered, including total, daytime, and nighttime accidents, as well as accidents involving tourists, nonuse of seat belts, and driving under the influence of alcohol. Grid-based characteristics were also considered, such as distance from the urban center, traffic volume, roadway length, transit use, land values, and roadway configuration (intersections versus dead ends). Although entropy plays a statistically significant role, especially for total accident counts, daytime accidents, and accidents involving tourists, the relationships involving effects such as volume, roadway length, distance to the central business district, and transit use are generally more readily detected than entropy effects. Although the research shed additional light on the complex and subtle relationships between land use and accidents, implications for both traffic safety and modeling of spatial phenomena were also apparent. Rather than examine accidents without consideration of driver characteristics and vehicle and roadway factors, this study estimated interactions between human and vehicle factors while also taking into account differences in environmental conditions and land uses that affect crashes at different spatial resolutions.