The state of roadside ditch design and performance has become a topic of concern for the Virginia Department of Transportation. Erosion failures of roadside ditches have occurred frequently enough to indicate that it may be desirable to revise the current design practice. Through the Virginia Transportation Research Council, VDOT has sponsored this research to investigate the state of design practice for these structures and to explore revisions to the design process resulting in a more economical design. To investigate the erosion problems, various VDOT personnel at each of Virginia's nine Construction Districts were interviewed with the intent to gain an understanding of roadside ditch performance in each District. When possible, field visits were made to sites experiencing erosion failure and soil samples were collected for analysis. In addition, experiences and design procedures in neighboring states were reviewed, with the objective of determining if similar problems have been experienced, and if so, how they have been addressed. The survey of other states included nine states, and a site visit to the Mount Airy District of the North Carolina Department of Transportation. A study of the literature relating to the hydraulic performance of unlined and lined ditches was also performed, with the objective of researching available stability criteria used in ditch design and determining if suitable values of Manning's n are being used in Virginia design. The results of this study presented in this thesis represent the best recommended roadside ditch design practice based on current available research. Recommendations include revisions to the current relationship of soil type and maximum allowable velocity, revisions to the application of Manning's n for various lining conditions, and suggestions to improve the overall design and construction process based on surveyed VDOT experience, surrounding states and current research. Future research will be necessary to improve the scientific bases for these recommendations / Master of Science

The focus of this research is Virginia’s Secondary Highway Construction System funding allocations and its impact on statewide deficient lane miles reduction. The research question guiding this study is: “Which of the four allocation models -- the current Secondary Highway System allocation model or one of three alternatives of this model based on Brian D. Taylor’s geographic equity categories (outcome, opportunity, and market) best maximizes statewide deficient lane miles reductions?” Taylor defines each of these geographic equity categories (independent variables for this study) for all levels of government. While Taylor’s research focus has been on equity as it relates to transit and congestion pricing, this study applied his construct to highways. As a result of scanning subjects related to transportation, the need for this study became apparent. Since the 1980’s, Virginia’s highway allocation formula has not changed (Virginia Department of Transportation, 2005). The Virginia General Assembly has sponsored follow-up studies through a series of resolutions over the years (Auditor of Pubic Accounts, 2004). To date, none of the legislatively sponsored research findings have prompted an update of Virginia’s highway allocation formula (Virginia Transportation Research Council, 2008). There is a significant academic and professional literature on federal transportation politics and specific transportation engineering issues. However, there is very limited research on the development of state level highway transportation funding methodologies. This study used the quantitative research approach, which is concerned with determining the relationship between one factor (an independent variable) and another (a dependent or outcome variable) in a population (Walker, 2005, Newman, 1998, and Geddes, 1990). Therefore, this study employed the quantitative research approach to study cause and effect (Mulhall, 2004, Loughborough, 1995, and Collier 1995) relationships of Virginia’s Secondary construction allocations to individual counties and statewide deficient lane miles reductions overall. The .20 portion of the formula for area was examined because this data rarely changes due to locality annexations. Conversely, the .80 portion of the formula was excluded from the analysis because of the demographic variability due to population shifts. As such, the Federal Highway Administration and states update population statistics from the decennial census with the apportionment of funds for formula based programs such as Virginia’s Secondary Highway Construction program (Federal Register, 2002). This researcher concluded that of the four geographic allocation models, the geographic opportunity equity maximized an additional 4.15 statewide deficient lane miles reductions over the baseline model. This study recommends using the geographic opportunity equity model when allocating Virginia’s Secondary Highway Construction funds to maximize the statewide deficient lane miles reductions above the baseline model, the geographic market equity model and the geographic outcome equity model.