Pradip Pant

Hit-and-Run Crashes: Use of Rough Set Analysis with Logistic Regression to Capture Critical Attributes and Determinants

In this paper, an innovative mathematical tool, rough set analysis (RSA), combined with logistic regression modeling, is used to understand the key factors associated with hit-and-run collisions in Hawaii. After a description of the nature of the problem in Hawaii and some background on the RSA, the methods are applied to a comprehensive database of police-reported accidents over the period 2002 to 2005. RSA is used to extract the key determinants of hit-and-run collisions. With the information from the RSA, a logistic regression model is built to explain the key factors associated with hit-and-run crashes in Hawaii. Factors such as being (a) a male, (b) a tourist, and (c) intoxicated and driving a stolen vehicle are strong predictors of hit-and-run crashes. In addition to the obvious human factors associated with these crashes, there are interesting roadway features, such as horizontal alignment, weather, and lighting, that are also significantly related to hit-and-run crashes. Some suggestions for reducing hit-and-run crashes as well as opportunities for additional research are identified.

Evacuation planning for plausible worst case inundation scenarios in Honolulu, Hawaii

Honolulu is susceptible to coastal flooding hazards. Like other coastal cities, Honolulu&s long-term economic viability and sustainability depends on how well it can adapt to changes in the natural and built environment. While there is a disagreement over the magnitude and extent of localized impacts associated with climate change, it is widely accepted that by 2100 there will be at least a meter in sea level rise (SLR) and an increase in extreme weather events. Increased exposure and vulnerabilities associated with urbanization and location of human activities in coastal areas warrants serious consideration by planners and policy makers. This article has three objectives. First, flooding due to the combined effects of SLR and episodic hydro-meteorological and geophysical events in Honolulu are investigated and the risks to the community are quantified. Second, the risks and vulnerabilities of critical infrastructure and the surface transportation system are described. Third, using the travel demand software, travel distances and travel times for evacuation from inundated areas are modeled. Data from three inundation models were used. The first model simulated storm surge from a category 4 hurricane similar to Hurricane Iniki which devastated the island of Kauai in 1992. The second model estimates inundation based on five tsunamis that struck Hawaii. A 1-m increase in sea level was included in both the hurricane storm surge and tsunami flooding models. The third model used in this article generated a 500-year flood event due to riverine flooding. Using a uniform grid cell structure, the three inundation maps were used to assess the worst case flooding scenario. Based on the flood depths, the ruling hazard (hurricane, tsunami, or riverine flooding) for each grid cell was determined. The hazard layer was analyzed with socioeconomic data layers to determine the impact on vulnerable populations, economic activity, and critical infrastructure. The analysis focused both on evacuation needs and the critical elements of the infrastructure system that are needed to ensure effective response and recovery in the advent of flooding. This study shows that the coastal flooding will seriously affect the economy and employment. Extreme flooding events could affect 38 percent of the freeways, 44 percent of the highways, 69 percent of the arterial roads, and 40 percent of the local streets in the area examined. Approximately 80 percent of the economy and 76 percent of the total employment in the urban core of Honolulu is exposed to flooding. Evacuation modeling, shelter accessibility, and travel time to shelter analyses revealed that there is a significant shortage in sheltering options, as well as increases in travel times and distances as inundation depth increases. The findings are useful for evacuation and shelter planning for extreme coastal events, as well as for climate change adaptation planning in Honolulu. Recommendations for emergency responders as well as those interested in the integration of long-term SLR and low probability, high consequence coastal hazards are included. The study shows how to integrate travel demand modeling across multiple hazards and threats related to evacuating, sheltering, and disaster risk reduction.

Managing uncertainty: Lessons from volcanic lava disruption of transportation infrastructure in Puna, Hawaii

A recent lava flow in Puna, Hawaii, threatened to close one of the major highways serving the region. This article provides background information on the volcanic hazards and describes events, responses, and challenges associated with managing a complex, long-duration disaster. In addition to the need to better understand geologic hazards and threats, there is a need for timely information and effective response and recovery of transportation infrastructure. This requires coordination and sharing of information between scientists, emergency managers, transportation planners, government agencies, and community organizations. Transportation assets play a critical role in terms of problem definition, response, and recovery. The challenges with managing a long-duration event include: (1) determining when a sufficient threat level exists to close roads; (2) identifying transportation alternatives; (3) assessing impacts on communities including the direct threats to homes, businesses, structures, and infrastructure; (4) engaging communities in planning and deliberation of choices and alternatives; and (5) managing uncertainties and different reactions to hazards, threats, and risks. The transportation planning process provides a pathway for addressing initial community concerns. Focusing not just on roadways but also on travel behavior before, during, and after disasters is a vital aspect of building resilience. The experience in Puna with the volcano crisis is relevant to other communities seeking to adapt and manage long-term threats such as climate change, sea level risk, and other long-duration events.

Using National Household Travel Survey Data for the Assessment of Transportation System Vulnerabilities

This paper describes how the National Household Travel Survey (NHTS) data can be used within the framework of the Threat and Hazard Identification and Risk Assessment, recently promulgated by the Federal Emergency Management Agency, to assess transportation system vulnerability. The purpose of this paper is threefold: identify common ground between the Department of Homeland Security and the Department of Transportation in methods of risk assessment; look specifically at transportation vulnerabilities by shifting the focus from transportation system infrastructure to the travel patterns and attributes of individuals; and with data from Honolulu, Hawaii, evaluate the vulnerability of transportation assets. The proposed transportation system vulnerability assessment method uses data from the 2001 NHTS Oahu, Hawaii, add-on survey and probable coastal inundation scenario for events caused by hurricane storm surge, inland flooding, and sea level rise. A geographic information system approach is used to simulate travel routes and assess the transportation system vulnerabilities for individuals and households. The NHTS data contain vital information regarding home, work, and other travel locations. The data also contain travel mode information that can be used to produce quantitative indices for exposure and vulnerability, which can be overlaid with plausible hazard and threat scenarios. Recommendations are made for improving the quality, availability, and usefulness of NHTS data for the reduction of risks. The findings are relevant to transportation research on risk assessment and threat and hazard reduction.

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.

Tsunami evacuation buildings and evacuation planning in Banda Aceh, Indonesia

Indonesia, a country of more than 17,000 islands, is exposed to many hazards. A magnitude 9.1 earthquake struck off the coast of Sumatra, Indonesia, on December 26, 2004. It triggered a series of tsunami waves that spread across the Indian Ocean causing damage in 11 countries. Banda Aceh, the capital city of Aceh Province, was among the most damaged. More than 31,000 people were killed. At the time, there were no early warning systems nor evacuation buildings that could provide safe refuge for residents. Since then, four tsunami evacuation buildings (TEBs) have been constructed in the Meuraxa subdistrict of Banda Aceh. Based on analysis of evacuation routes and travel times, the capacity of existing TEBs is examined. Existing TEBs would not be able to shelter all of the at-risk population. In this study, additional buildings and locations for TEBs are proposed and residents are assigned to the closest TEBs. While TEBs may be part of a larger system of tsunami mitigation efforts, other strategies and approaches need to be considered. In addition to TEBs, robust detection, warning and alert systems, land use planning, training, exercises, and other preparedness strategies are essential to tsunami risk reduction.

Sustaining Seat Belt Use in a High-Use State

Hawaii has been a high-use state for seat belts since 1985. For the past decade, the state has averaged well over 95% overall compliance. Efforts to maintain or even increase this exceptional use rate are challenging. Hawaii has a large tourist population. Nonusers may come from demographic and social groups that are difficult to reach. This paper summarizes two decades of monitoring, research, and evaluation of programs in Hawaii and suggests several aspects of the states success in promoting seat belt use. A key component involves understanding the geography of seat belt use and the relationships between enforcement activities and public outreach and education. Although it may be difficult or impossible to attain universal use, some directions for further effort in promoting seat belt use in high-use communities are clearly possible. This research will be increasingly important as other communities achieve higher use rates and transition to efforts geared toward sustaining seat belt use. Enforcement is part of an overall program for increasing seat belt use and traffic safety.