This paper presents the results of an experimental study aimed at determining the impact of porous asphalt on the quality of stormwater runoff on highways with a curb and gutter drainage system. A porous overlay, also known as permeable friction course (PFC), is a layer of porous asphalt applied to the top of conventional asphalt highways at a thickness of 50 mm to improve safety and water quality and reduce noise. The quality of highway stormwater runoff was monitored before and after the installation of PFC on an eight-lane divided highway in the Austin, Texas area for 15 months. Observed concentrations of total suspended solids from PFC are more than an 80% lower than from the conventional pavement. Concentration reductions are also observed for nitrate/nitrite and total amounts of phosphorus, copper, lead, and zinc. The data shows that the results with curb and gutter are consistent with past results where runoff sheet flowed onto vegetated shoulders. / text

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In an effort to motivate contractors to complete construction projects early on high-impact highway pavement construction projects, state transportation agencies (STAs) including TxDOT have often used incentive/disincentive (I/D) contracts. However, determining I/D rates is extremely difficult due largely to the lack of systematic methods for helping STAs determine effective I/D rates. The primary goal of this project is to develop a novel framework for determining the most realistic and economical I/D dollar amounts for high-impact highway improvement projects. To achieve its goal, this project proposes an integration analysis including project schedule and the lower and upper bounds of the I/D contract. The lower bound is the contractor’s additional cost of acceleration, and the upper is the total savings to road users and to the agency. The study data were gathered using Construction Analysis for Pavement Rehabilitation Strategies (CA4PRS) software. These data were then grouped by four different types of pavements, namely Joint Plain Concrete Pavement (JPCP), Continuously Reinforced Concrete Pavement (CRCP), Hot Mix Asphalt (HMA), and Milling and Asphalt Concrete Overlay (MACO). With these data, a series of regression analyses were carried out to develop predictive models for the validation of time-cost tradeoff to determine I/D lower bound. Road user cost and agency cost savings were quantified using CA4PRS to develop lookup tables to determine I/D upper bound. Adjustment of contractors’ additional cost of acceleration with Level of Service (LOS) and total savings adjustment using Net Present Value (NPV) were incorporated in the research study to calculate point based estimates of I/D for lower and upper bound, respectively. Lastly, case studies on real world projects were conducted to evaluate robustness of the model. The research results reveal that the predictive models give appropriate results for the case studies in determining the I/D dollar amount for the lower and upper bound. This study will provide the research community with the first view and systematic estimation method that STAs can use to determine the most economical and realistic I/D dollar amount for a given project–an optimal value that allows the agency to stay within budget while effectively motivating contractors to complete projects ahead of schedule. It will also significantly reduce the agency’s expenses in the time and effort required for determining I/D dollar amounts.

The last decade has seen significant developments in highway asset management. A key component to successful asset management is long-term network investment planning. In order to successfully manage a significant quantity of aging roadway infrastructure and growing traffic volume, agencies are faced with challenges in developing reliable long term plans that maximize the network performance through value optimization. Current practice typically involves relatively independent planning for the bridge and pavement networks; with a very slight number of situations allowing for reliable trade-off analysis between the two. While a situation in which the choice to improve two structures rather than one pavement section may yield a greater percentage increase in the bridge network performance, than the opposite choice would for the pavement network - the reliability of this choice being right and at the right time significantly decreases over time. Introduction of mutually inclusive highway asset planning in this research, by integration of the bridges into an equivalent measure of the pavement network results in significant increases in the long-term planning reliability - is proposed. Data from the Ministry of Transportation of Ontario is used to demonstrate how this proposed approach would work. A key point of this Strategic Total Highway Asset Management Integration (STHAMi) approach is the Conceptual Structural Integration Factor (CSIF). Application of CSIF and Bridge Condition Index (BCI) integration into a pavement performance index allows for representation and treatment of bridges as equivalent pavement sections. This allows for a better comparison of the assets over time. Compared to the traditional approach of mutually exclusive network level planning, STHAMi resulted in a higher percentage of network treated per unit of value, coupled with consistently higher annual network performance over the long-term. In addition to significantly higher long-term sub-asset trade-off reliability, STHAMi offers potential for significant increases in organizational efficiency with respect to longterm highway asset planning. Key benefits include introduction of one pavement performance indicator as an all encompassing performance indicator for the complete highway asset, as well as the potential for long-term bridge network level planning execution within a pavement engineering oriented organizational unit. Further STHAMi development is recommended through integration of other network performance measures such as operational and safety indicators.

The aim of this research project is to improve our understanding of how planning policies, which seek to influence patterns of land use and activities, can promote changes in travel behaviour towards 'more sustainable transport', with particular reference to metropolitian transport corridors. / Thesis (PhD)--University of South Australia, 2006.

Thesis (M.C.E.)--University of Delaware, 2008. / Principal faculty advisor: Sue McNeil, Dept. of Civil & Environmental Engineering. Includes bibliographical references.

Thesis (M. S.)--Civil and Environmental Engineering, Georgia Institute of Technology, 2008. / Committee Chair: Kurtis, Kimberly; Committee Member: Kahn, Lawrence; Committee Member: Sobecky, Patricia.

Thesis (Ph. D.)--Universitäts Karlsruhe, 2007. / Includes bibliographical references (p. 129-142). Also available online.

Thesis (M.P.H.)--University of Michigan, 1944.