The purpose of this research is to develop an intersection safety evaluation tool that is capable of assisting designers and planners in the assessment of alternative intersection designs. A conflict exposure model utilizing design hour volumes, intersection configuration and traffic control measures is proposed to achieve this goal. This approach makes use of data typically available for preliminary intersection design. The research goes beyond existing safety performance models which only examine non-directional average daily traffic (ADT) or practices which only account for the geometric and lane configuration of an intersection, such as conflict point analysis. Conflict prediction models are developed for left-turn angle, right-turn, rear end and sideswipe crashes. These models were developed through the analysis of over 1000 simulation scenarios evaluating a full range of approach and turning volumes, lane configurations and traffic control strategies. The quantifiable metrics provided can be used to inform and improve alternative intersection selection processes by differentiating between alternatives based on a surrogate safety performance. This research may be used in screening of intersection alternatives to select the most beneficial design based on objective safety performance metrics.

This thesis contains the results from researching historic gas stations along U.S. 40 in Indiana and from exploring the effects of the automobile and oil industries on the evolution of this building type. It reaches conclusions about how the stations in the study area differ from national design trends and from the prototypes created by major oil companies.Of the major gas station design types, only residential and oblong box stations were found in the study area. Since the other design types were common across the country, it is reasonable to assume that such structures also appeared in Indiana and have subsequently been demolished. Although not all types and styles were found in the study area, those that were found were comparable in form and design to other stations throughout the country.Ultimately, this thesis is a case study of gas stations in Indiana. It can be used to evaluate stations throughout the state and provides a framework for further research on gas stations along other Indiana highways. / Department of Architecture

A practical and reliable alternative or supplement to injury accident data is necessary to diagnose dangerous sites and evaluate remedial measures because available accident data is scarce, is lacking in detail about the events preceding the accident and it takes a long time to accumulate statistically reliable data. The most favoured alternative is the Traffic Conflicts Technique which satisfies most of the requirements of a supplementary measure, but has so far only been successfully validated for rural dual carriageway intersections (Spicer, 1973). To establish the technique it is necessary a) to ensure that the subjective judgements on which it is based are reliable, b) to develop the best methods of recording conflicts, and of training and selecting observers, and then c) to test the validity of the best available technique. The main part of this thesis reports three studies aimed at each one of these issues. In the first study intra observer reliability tested on filmed material varied between rs = 0.30 and 0.91 (0.65 overall for N = 42), but poor observers could be identified. By selecting the best observers an overall reliability figure of up to 0.88 could be obtained. Reliable observers remained reliable or even improved slightly on the second testing. These reliable observers also showed good agreement with expert judges who had viewed the film many times, and by selection a correlation with the criterion value of up to 0.83 could be obtained. In the second study a new recording method was developed, incorporating factors that experienced observers used to differentiate the grades of severity currently in use. This helped observers by defining the criteria for detection and grading of a conflict more objectively. This increased the overall intra observer reliability from 0.73 to 0.80, and agreement with the criterion values from 0.66 to 0.76. Transfer from laboratory to field led to a drop in the numbers of conflicts reported. From these studies and a survey of the requirements of local authority accident investigation units, a manual and training package was developed giving guidance on training and selecting observers for the purpose of obtaining reliable conflict data, such as that required for validating the technique. In the third study this package was validated in a study of a sample of eight urban T-junctions. Again the best observers were selected and found to have an overall reliability of 0.88. It was found that, when rear end conflicts were excluded (on the grounds that they led to so few reported injury accidents while occurring in large numbers), there was a high correlation between accidents per vehicle and conflicts per vehicle (rs = 0.79, p<0.025), accounting for 62% of the variance. This compares very favourably with the maximum possible percentage (77%) which could be expected given the relaibility (rs = 0.88) of the observers. Although a validity correlation of 0.79 is very satisfactory and the method of obtaining the data is reasonably economical, an attempt was made to find a still more economical alternative to accident statistics. The most obvious of these are subjective judgements or a combination of these with traffic flow. Traffic flow data for different manoeuvres at each of the eight T-junction sites were obtained and various groups of people were asked to judge the subjective risk of these sites from scale maps and photographs or directly on-site. Judgements from maps and photographs tended to be negatively correlated with accidents. The best subjective estimate (driving instructors judging on-site) correlated 0.44. An attempt to improve on these by combining the traffic flows and judged risk of the different manoeuvres at each site failed to produce a higher correlation. None of these correlations were significant, but the failure of any one of several different corrrelations to be higher than 0.46 suggests very strongly that these simpler methods are very unlikely to have the validity of the full conflicts technique. However, the present study has validated the Traffic Conflicts Technique only for urban T-junctions (the commonest of all accident sites). It could, therefore, only be used for evaluating the effects of small changes in the layout of such junctions. It could be used to evaluate more radical changes eg. T-junction converted to a mini roundabout, provided the conflict to accident ratios of the different layouts were known. In this study the conflict to accident ratio was 125:1 for vehicles turning right out of the minor road. For the T-junctions as a whole it was 275:1 while Older and Spicer(1976) found a ratio of 2000:1 for rural dual carriageway intersections. By obtaining more information of this kind, the utility of the Traffic Conflicts Technique could be greatly extended.

This project researched the fungal and bacterial communities (i.e. biofilms) found on concrete infrastructure in Georgia. Various microbial communities were sampled from four geographically separated sites. The species present in these biofilms were identified through DNA analysis and cultured for testing. A new, rapid test method was developed to accurately simulate field growth conditions in a laboratory environment. Using the newly developed test method, these communities were grown on small mortar tiles, which varied in w/cm, surface roughness, cement type (including photocatalytic cement), and supplementary cementing materials. This research determined that photocatalytic cement was the most effective in decreasing biofilm growth under artificial daylight, but did not increase or decrease growth when not exposed to light. The next most effective ways to decrease growth were lowering w/cm and decreasing surface roughness. The supplementary cementing materials examined did not increase or decrease biofilm growth.

Accurate client budget estimates are critical to the initial decision-to-build process for the highway construction projects. This decision-to-build point in a project's development is seen as the international standard for measuring any subsequent cost estimate inaccuracies involved (National Audit Office/Department of Transport, 1992; World Bank, 1994; Nijkamp and Ubbels, 1999), with accuracy being defined as the difference between the initial project estimate at the decision-to-build stage and the real, accounted project cost determined at the time of project completion. Expressed as a percentage of estimated cost, this is often termed cost escalation, cost overrun or cost growth, and occurs as a result of many factors, some of which are related to each other, but all are associated with forms of risks. The analysis of these risks is often a necessary step for the improvement of any given estimating system and can be used to diagnose trouble spots and to pinpoint areas where project estimating accuracy improvement might be obtained. In this research, highway projects in Queensland, Australia that have suffered significant cost overrun are analysed. The research seeks to address the gap in the knowledgebase as to why highway projects overrun their costs. It focuses on understanding how client projects budgets go wrong, when dealing with project risk. The foundation for this research is drawn from the post-mortem analysis of highway projects, each costing in excess of A$1m and whose final total expenditure exceeded budget by 10% or greater. The research identifies client risk variables which have contributed to significant cost overrun and then uses factor analysis and also expert elicitation, using nominal group technique, to establish groups of importance ranked client risks. Stepwise multivariate regression analysis is then used to investigate any correlation of these risks, along with project attributes such as highway project type, indexed project cost, geographic location and project delivery method to the percentage of cost overrun. The research results indicates a correlation between the reciprocal of project budget size and percentage cost overrun that can be useful in clients determining more realistic decision-to build highway budget estimates when taking into account project size in relation to economy of scale.

Thesis (PhDTransportSystemsEngineering)--University of South Australia, 2003.

Thesis (M.F.)--Oregon State College, 1958. / Typescript. Includes bibliographical references (leaves 46-47). Also available on the World Wide Web.

Thesis (M.C.E.)--University of Delaware, 2007. / Principal faculty advisor: Sue McNeil, Dept. of Civil & Environmental Engineering. Includes bibliographical references.

Thesis (M. App. Sc.)--Carleton University, 2004. / Includes bibliographical references (p. 157-163). Also available in electronic format on the Internet.

Thesis (Ph.D.) - Carleton University, 2005. / Includes bibliographical references (p. 154-166). Also available in electronic format on the Internet.