Master of Regional and Community Planning / Department of Landscape Architecture/Regional and Community Planning / Hyung Jin Kim / This study seeks to investigate the impact of inner-city highways on walkability in urban downtowns in the United States, using Greater Downtown Kansas City as a case study. This study used the web-based online survey method to assess if inner-city highways impede the flow of pedestrians among residents and visitor of the Greater Downtown Kansas City, Missouri. The results showed that there were differences in the perception of the pedestrian environment between residents and visitors of the downtown area. Downtown residents generally had a more favorable view of the pedestrian environment than visitors of Greater Downtown. Additionally, the inner-city highways did not appear to be barriers to pedestrian mobility, which differs from the hypothesis of this study. However, although the pedestrian overpasses over the highways did have an impact on pedestrians’ perceptions and walking behaviors, newer overpasses with wider sidewalks mitigated barrier effects of highways more than older overpasses with narrow sidewalks. The study also found that walking was the most common travel mode for all trips in Greater Downtown Kansas City, despite potential barriers.

The increase of road infrastructure around the world involving the traditional hot mix asphalt (HMA) technology and its effects on the environment and health means that serious attention needs to be paid to building more sustainable flexible pavements. Cold bitumen emulsion mixture (CBEM) as an increasingly attractive cold asphalt mixture is therefore becoming an important subject area for study. Despite the efforts applied during the last few decades to enhance and develop CBEM application, certain issues still exist that make it inferior to HMA, resulting in limiting or minimizing its use. However, the enhancement of CBEM for flexible pavements construction, rehabilitation and maintenance is increasingly gaining interest in both pavement engineering industrial and research sectors. Therefore, the main aim of this study is to gain a deep insight and understanding into the impact response of using natural and synthetic fibres as reinforcing materials, on the mechanical properties and water susceptibility of CBEM including indirect tensile stiffness and resistance to rutting, cracking and moisture damage. Four different types of fibres were used: glass as a synthetic fibre, and hemp, jute and coir as natural fibres. Various samples of CBEM, with and without fibres, were fabricated and tested. Traditional hot mix asphalt mixture was also used for comparison. By achieving this aim it is expected that the use of CBEM would increase, allowing such mixtures to be used as structural pavement materials with some confidence. In spite of the quality of an asphalt mix being one of the most important and significant factors that affect the performance of both hot and cold mix flexible pavements, and the high quality mixes are often cost effective as these mixes require less maintenance and increase the service life of the pavements, it is also cost efficient to replace the semi-experimental flexible pavement design methods with fast and powerful software that includes finite element analysis. Several finite element models (FEM) have been developed to simulate the behaviour of hot mix asphalt, but none exists for cold mix asphalt reinforced by natural and synthetic fibres. This study also describes the development of a three-dimensional (3-D), finite element model of flexible pavements made with CBEMs, which has itself been reinforced with natural and synthetic fibres. The 3-D finite element model was employed to predict the viscoelastic and viscoplastic responses of flexible pavements based on CBEM when subjected to different multiple axle loads, bituminous material properties, tyre speeds and temperatures. The pavements were subject to moving and static loading conditions to test for permanent deformation (rutting). The results indicate a significant improvement in the indirect tensile stiffness modulus, for all fibre-reinforced CBEMs, over different curing times. The improved tensile behaviour represents a substantial contribution towards slowing crack propagation in bituminous mixtures, while scanning electron microscopy analysis confirmed the fibre shape and surface roughness characteristics. The improved performance of the reinforced mixtures with both natural and synthetic fibres facilitated a substantially lower permanent deformation than traditional hot and cold mixtures at two different temperatures (45 °C and 60 °C). When using glass and hemp fibres as reinforcing materials, there was a significant improvement in CBEM in terms of water sensitivity. These reinforcing materials can extend the service life of flexible pavements. Finally, the results show that the finite element model can successfully predict rutting of flexible pavements under different temperatures and wheel loading conditions.

Typescript (photocopy). / Digitized by Kansas Correctional Industries

This research developed a new methodology and new models for assessing the potential of motorcycle crashes and selecting countermeasures to improve motorcyclist safety in a motorcycle-dominated traffic environment of urban roads. The crash risk models were developed based on discrete choice models and traffic conflict techniques. The innovative features of this research are that the non-lane-based movements of motorcycles were captured to evaluate their contributions to crash risk and a new concept - that of the Conflict Modification Factor (CoMF) - was proposed to use as a surrogate measure to assess the relative contribution of risk factors to crashes. In addition, a methodology was also developed to enhance the existing International Road Assessment Programme (iRAP) star rating system for motorcyclists. The developed models were fitted and validated using data collected from urban roads in the city of Danang in Vietnam. The operating speed, speed difference, traffic density, front distance, longitudinal gap, lateral clearance and road surface condition were found to significantly contribute to motorcycle crash risk and several countermeasures have been consequently identified to improve motorcyclist safety including: installing changeable speed limit signs, installing changeable gap warning signs, installing changeable road surface condition warning signs and providing segregated motorcycle lanes.

Highway engineers have addressed the problem of pavement maintenance by developing remaining life assessment methods based on structural analysis of computer simulations of pavements tested in the field by non-destructive testing devices such as the Falling Weight Deflectometer (FWD). However the methodologies followed have been shown to be unable to provide accurate solutions without undue reliance on the knowledge of the expert engineer who conducts the analysis. A knowledge-based system (KBS) is proposed to "inject" engineering knowledge into the conventional techniques. It has been established on a systematic basis and seeks to cover the variety of the issues which may be encountered in such systems. In its prototype form the system consists of three parts: 1. The finite element analytical program ROSTRA-1. 2. A deductive database. 3. A back-analysis subsystem. The analytical program carries out the analysis of the pavements tested in the field. The deductive database holds the properties of a variety of paving materials and establishes the analytical model. The back-analysis subsystem seeks to perform the tasks required for the analysis of the FWD deflection bowl. To build this system, the POPLOG-Prolog computer language operated under VAX/VMS was selected to work in connection with the analytical program. An evaluation procedure was carried out to investigate the performance characteristics of the prototype system. The results indicated that the POPLOG-Prolog development environment is not the ideal tool for such an application. In addition, it appears unlikely that there is any other development tool available which is markedly more effective than that used. However it is felt that similar functions to those required by the POPLOG-Prolog environment, may be implemented using conventional programming. To permit this, a logical design of a KBS to conduct this task is presented.

The performance of roads is known to progressively reduce as a result of separate and interactive effects of climate and traffic. Existing decision support tools such as HDM-4, which are widely used to investigate long-term road maintenance strategies, utilise past climate data instead of future climate predictions. Uncertainties inherent in future climate predictions however imply that application of such tools could lead to outputs that are not robust in light of climate change. The objectives of the study were threefold: firstly, to develop a rut depth prediction model that considered potential effects of future climate; secondly, to formulate a framework for quantification of uncertainties; and finally, to demonstrate the application of the tools developed using a case study. The model was developed using data provided by the UK Highways Agency and UK Climate Impacts Programme. The methodology used was based on Bayesian regression. The developed model was found to perform better than the current asphalt surfacing rut depth model implemented in HDM-4 when future climate data was used. It was concluded that probabilistic outputs from the tools developed including deterioration rates, pavement condition and discounted maintenance costs for each maintenance strategy, and future climate and socio-economic scenarios provide a useful decision making framework for considering alternative strategies for road maintenance on the basis of the level of climate change risks that can be tolerated.

No description available.

Flexible pavements are environmentally sensitive elements of infrastructure and their performance can be influenced by climate. Climate change poses a challenge to design and management of flexible pavements in the future. Climate change can occur worldwide and thus all flexible pavements can be exposed to the impact. However, an assessment framework is not available to evaluate the impact of climate change on flexible pavements in terms of performance, maintenance decision-making and the subsequent life-cycle costs (LCC). This research has attempted to develop such a framework. Case studies on six flexible pavement sections from the United States were performed to demonstrate the application of the framework. The framework started with the investigation of climate change using IPCC’s (Inter-governmental Panel on Climate Change) climate change projections. Combinations of climate change projections and local historical climate were adopted as climatic inputs for the prediction of pavement performance. The Mechanistic-Empirical Pavement Design Guide (MEPDG) was used for prediction of pavement performance because it can provide reliable performance predictions with consideration of climatic factors. Pavement performance predictions were applied to schedule maintenance interventions. Maintenance effects of treatments were considered in maintenance decision-making. Maintenance effect models of International Roughness Index (IRI) and rutting were validated using pavement condition survey data from Virginia. With selected climate related LCC components, three maintenance interventions were optimised using a genetic algorithm to achieve the minimum LCC. Eventually the outputs of the system including pavement performance, intervention strategies, and LCC can be compared under various climate change and baseline scenarios. Hence, the differences in performance, decision-making, and LCC due to climate change can be derived. The conclusions were drawn based on the scheme of maintenance decision-making. If flexible pavements are not maintained (Alternative 0), an increase in LCC will be incurred by climate change due to an increase in road roughness (IRI). For pavements maintained with strict thresholds (Alternative 1), climate change may lead to a significant reduction in the service life when the maintenance is triggered by climate sensitive distress. However, benefit can be gained from decreasing LCC as the earlier triggered maintenance may result in less average IRI. As a consequence, user costs, which can be associated with IRI, can be reduced. Hence, LCC can be reduced as user costs usually dominate LCC. However, the net present value (NPV) of agency costs can be increased due to the early intervention. For pavements with optimised maintenance (Alternative 2), the LCC is almost unaffected by climate change. However, the type or application time of interventions may need to be changed in order to achieve this. Furthermore, the balance between agency and user costs did not seem to be influenced by climate change for Alternative 2. Agencies should be aware that maintenance optimisation can significantly reduce the LCC and make the best use of treatments to mitigate the effects of climate change on flexible pavements. Pavement maintained with strict triggers may require earlier interventions as a result of climate change but can gain benefit in LCC. However, this indicates that a responsive maintenance regime may not take full advantage of interventions and that maintenance could be planned to be performed earlier in order to achieve minimised LCC. Due to climate change, road users may spend more on fuels, lubricants and tyre wear on flexible pavement sections that do not receive any maintenance treatments.

The estimated value of the U.S. transportation infrastructure is over $7.0 trillion. The challenge is preserving the quality of the investment. State and federal departments of transportation have methods and procedures for best quality, but vary significantly. With the variations comes opportunity to assess the cost-effectiveness of different strategies and make recommendation on practices that are most successful. A survey was created and sent to all 50 states and the District of Columbia. The survey was aimed to capture information on construction finished product testing methods, optimized/reduced sampling techniques, innovative QA practices that measure multiple performance criteria and QA processes that are rapid and cost effective. There are many testing methods and procedures being used throughout the U.S. This thesis will allow state and federal transportation agencies to look at the findings and possibly implement them into their own agency with hopes of saving time and money for future projects.

This thesis is a preliminary archaeological predictive model and project-planning tool created for the Oregon Department of Transportation (ODOT) as part of a statewide planning effort to enhance the agency's ability to assess the potential impacts of highway projects on archaeological resources. This model addresses the archaeological sensitivity of the US 30 highway corridor from Portland, Oregon to Astoria, Oregon. The highway corridor is divided into 7 separate segments for management purposes and each segment is given a low, medium, or high probability rating for its potential to yield archaeological resources in this model. The ratings are accompanied by planning and maintenance recommendations to be integrated into a comprehensive planning document for the corridor. Probability determinations are based on State Historic Preservation Office (SHPO) archaeological records, physiographic data, dominant vegetation zones, General Land Office maps, ethnographic accounts, and historical records. The precise utility of this model is unknown because cross-tabulations that compare actual and model assigned presence or absence of resources have not been made. Low probability ratings are assigned to 27% of the corridor. Medium probability segments comprise 15% of the corridor. High probability rating account for 58% of the total length of the corridor. The segment with the highest site density is segment 2, averaging .63 archaeological sites per mile. The archaeological probability ratings were initially omitted from the Draft Corridor Management Plan of 1998, but have been included in the Final Corridor Management Plan of 1999. The predictive model results were incorrectly added to the document and consequently create false impressions. In the Final Corridor Management Plan the number of sites listed for segment 2 is incorrect. It is indicated that seven archaeological sites are present within the corridor, but the actual number is fourteen. Furthermore, the percentage ratings of low, medium, and high archaeological probability are erroneously provided for segments 3, 4, and 7 in the final plan. Ultimately this report has proven useful to ODOT archaeological staff, however signs indicate that the data provided to planning personnel has had little impact on project planning and design. / Graduation date: 2003