Samantha Islam

Comprehensive analysis of single- and multi-vehicle large truck at-fault crashes on rural and urban roadways in Alabama

The research described in this paper analyzed injury severities at a disaggregate level for single-vehicle (SV) and multi-vehicle (MV) large truck at-fault accidents for rural and urban locations in Alabama. Given the occurrence of a crash, four separate random parameter logit models of injury severity (with possible outcomes of major, minor, and possible or no injury) were estimated. The models identified different sets of factors that can lead to effective policy decisions aimed at reducing large truck-at-fault accidents for respective locations. The results of the study clearly indicated that there are differences between the influences of a variety of variables on the injury severities resulting from urban vs. rural SV and MV large truck at-fault accidents. The results showed that some variables were significant only in one type of accident model (SV or MV) but not in the other accident model. Again, some variables were found to be significant in one location (rural or urban) but not in other locations. The study also identified important factors that significantly impact the injury severity resulting from SV and MV large truck at-fault accidents in urban and rural locations based on the estimated values of average direct pseudo-elasticity. A careful study of the results of this study will help policy makers and transportation agencies identify location specific recommendations to increase safety awareness related to large truck involved accidents and to improve overall highway safety.

Pedestrian at-fault crashes on rural and urban roadways in Alabama

The research described in this paper explored the factors contributing to the injury severity resulting from pedestrian at-fault crashes in rural and urban locations in Alabama incorporating the effects of randomness across the observations. Given the occurrence of a crash, random parameter logit models of injury severity (with possible outcomes of major, minor, and possible or no injury) for rural and urban locations were estimated. The estimated models identified statistically significant factors influencing the pedestrian injury severities. The results clearly indicated that there are differences between the influences of a variety of variables on the injury severities resulting from urban versus rural pedestrian at-fault accidents. The results showed that some variables were significant only in one location (urban or rural) but not in the other location. Also, estimation findings showed that several parameters could be modeled as random parameters indicating their varying influences on the injury severity. Based on the results obtained, this paper discusses the effects of different variables on pedestrian injury severities and their possible explanations. From planning and policy perspective, the results of this study justify the need for location specific pedestrian safety research and location specific carefully tailored pedestrian safety campaigns.

Issues, Practices, and Needs for Communicating Evacuation Information to Vulnerable Populations

Effective communication of transportation-related information to vulnerable populations is a critical need during emergencies. Despite its importance, various factors still hinder the development of comprehensive and effective plans for communicating emergency information to mobility-limited individuals during evacuations and other major emergencies. Such limiting factors include the wide diversity of vulnerable populations, their special needs, existing contact and communication barriers, and lack of resources and mechanisms to locate those populations and assist them during emergencies. This paper illustrates the complexity of communicating with vulnerable populations in emergency evacuations through a critical review of the existing literature and state-of-the-practice information gathered recently from transportation and emergency management agency personnel. First, the paper reviews definitions, characteristics, and size of the vulnerable population. Next, principles of effective communication and the special provisions for communicating with vulnerable populations are presented, along with examples of effective communications and communications barriers. Finally, the paper identifies numerous important emergency evacuation communications topics that were not discussed in the literature and offers recommendations for bridging those gaps. Examples include the limited involvement of experts in emergency evacuation communication, the lack of information about the financial aspects and cost-effectiveness of such communications, the need to establish an information clearinghouse to assist in future evacuations, and the lack of standardization and cataloging of appropriate evacuation messages. The paper is presented as a foundation for developing a framework for effective communications strategies, policies, and practices that focus on vulnerable populations before, during, and after all-hazards emergencies.

A comparative injury severity analysis of motorcycle at-fault crashes on rural and urban roadways in Alabama

The research described in this paper explored the factors contributing to the injury severity resulting from the motorcycle at-fault accidents in rural and urban areas in Alabama. Given the occurrence of a motorcycle at-fault crash, random parameter logit models of injury severity (with possible outcomes of fatal, major, minor, and possible or no injury) were estimated. The estimated models identified a variety of statistically significant factors influencing the injury severities resulting from motorcycle at-fault crashes. According to these models, some variables were found to be significant only in one model (rural or urban) but not in the other one. For example, variables such as clear weather, young motorcyclists, and roadway without light were found significant only in the rural model. On the other hand, variables such as older female motorcyclists, horizontal curve and at intersection were found significant only in the urban model. In addition, some variables (such as, motorcyclists under influence of alcohol, non-usage of helmet, high speed roadways, etc.) were found significant in both models. Also, estimation findings showed that two parameters (clear weather and roadway without light) in the rural model and one parameter (on weekend) in the urban model could be modeled as random parameters indicating their varying influences on the injury severity due to unobserved effects. Based on the results obtained, this paper discusses the effects of different variables on injury severities resulting from rural and urban motorcycle at-fault crashes and their possible explanations.

Comparative analysis of injury severity resulting from pedestrian-motor vehicle and bicycle-motor vehicle crashes on roadways in Alabama

A comparison is provided between the influence of a variety of variables and the injury severities resulting from pedestrian-motor vehicle and bicycle–motor vehicle crashes in Alabama with the incorporation of the effects of randomness across the observations. Given the occurrence of a crash, random parameter logit models of injury severity with possible outcomes of fatal, major, minor, and possible or no injury were estimated. The estimated models identified a variety of statistically significant factors influencing pedestrian and bicyclist injury severities. According to these models, some variables were found to be significant in only one model (pedestrian or bicycle) but not in the other. For example, variables such as roadway crossing, crashes on Saturdays, and crashes on private roadways were found significant only in the pedestrian model. By contrast, variables such as the use of retroreflective clothing, crashes during the evening peak hour, and crashes in summer were found significant only in the bicyclist model. In addition, some variables—such as older pedestrians and bicyclists, dark roadway, and low-speed roadway—were found significant in both models. Also, estimation findings showed that three parameters in the pedestrian model (between midnight and 7:00 a.m., clear weather, and at intersections) and two parameters in the bicycle model (level grade on tangent and clear weather) could be modeled as random parameters; these findings indicated their varying influences on injury severity. From the results obtained, the effects of different variables on pedestrian and bicyclist injury severities and their possible explanations are discussed.

Comprehensive Injury Severity Analysis of SUV and Pickup Truck Rollover Crashes

The research described in this paper explored the factors contributing to injury severity resulting from rollover accidents of light trucks—SUVs and pickups in particular—in Alabama. Given the occurrence of a rollover crash, random parameter logit models of injury severity (with possible outcomes of fatal, major, minor, and possible or no injury) were estimated. The estimated models identified a variety of statistically significant factors influencing the injury severities resulting from SUV and pickup rollover crashes. According to these models, some variables were significant in one model (SUV or pickup) but not the other. For example, variables such as roadway downgrade, female drivers, and daylight were significant only in the SUV model. Variables such as driver fatigue, driver or occupant wearing a seat belt, and freeway were significant only in the pickup model. In addition, some variables (such as not wearing a seat belt, two-lane roadway, horizontal curve, and old driver) were significant in both models. Estimation findings showed that two parameters (horizontal curve and at intersections) in the SUV model and two parameters (horizontal curve and dry roadway surface) in the pickup model could be modeled as random parameters, indicating their varying influence on the injury severity related to unobserved effects. The results obtained are used in this paper for a discussion of the effects of variables on pedestrian and bicyclist injury severities and their possible explanations.

Economic assessment of dredging operations in Mobile Bay, USA and some additional notes on sustainable management of dredged material

This paper describes a study that was performed to determine the cost-effective method of dredging in Mobile Bay in the United States and to explore the possibility of utilizing the dredged materials in an environmentally sustainable way. An analysis of the historical cost and working time data for hopper dredging and pipeline dredging for Mobile Bay showed that there was not a substantial difference in unit costs between the two methods. However, while the disposal methods for dredged materials were taken into consideration, the pipeline dredging seemed to be a more desirable and environmentally friendly option for dredging in Mobile Bay. In addition to cost analysis, the paper discusses several possible ways of sustainable management of dredged materials. The paper also indicates that if the sediment in Mobile Bay is found to be contaminated by the Deepwater Horizon oil spill, the pipeline dredging will become a more desirable dredging alternative.