Browsing by Subject "Highway"
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Item An investigation of passing operations on a rural, two-lane, two-way highway with centerline rumble strips(Texas A&M University, 2005-02-17) Miles, Jeffrey DavidThe research in this thesis was conducted to investigate the initial stage of passing maneuvers on a rural, two-lane, two-way (RTLTW) highway with centerline rumble strips (CRSs). Four measures of effectiveness were used: (1) number and type of erratic movements by a passing vehicle, (2) number of and time between centerline encroachments of a passing vehicle, (3) gap distance of a passing vehicle, and (4) centerline crossing time. Data were collected for a before-and-after analysis at one site, in Comanche County, Texas. The test section was on US 67 from Comanche, Texas to the county line south of Dublin, Texas. The posted speed limit for this RTLTW highway was 70 mph during the day. CRSs were installed along approximately 15 miles of US 67. Only one test design for CRSs was installed. The design specification was for a CRS to be milled to a 0.5-inch depth, 7-inch length, and 16-inch width. This specification was developed from current state practices throughout the United States. CRSs were installed continuously through passing and no-passing zones, and they were spaced at 24 inches on-centers. Pavement markings were striped over the CRSs. Data were collected using an innovative data collection system developed by the author through the Texas Transportation Institute (TTI). This system was mounted to a four-door sedan, and it consisted of four concealed cameras that recorded the entire passing maneuver around the data collection vehicle. Data were collected at three different speeds during the daytime. The speeds were 55, 60, and 65 mph (15, 10, and 5 mph, respectively, under the posted speed limit). Based on the assessment of the four MOEs, the overall finding of this thesis was that driver performance during the initial phase of passing maneuvers was not negatively impacted after the installation of CRSs on US 67. The caveat is that differences in the weather conditions may have influenced the results. The weather was dry with clear skies at the study site during data collection prior to the installation of CRSs; however, the weather consisted of intermittent rain during the data collection after the installation of CRSs.Item Identification of potential strategies, methods, and tools for improving cost estimating practices for highway projects(Texas A&M University, 2005-08-29) Donnell, Kelly ElaineProject cost escalation is a major problem for State Highway Agencies (SHA). This problem is evident in cost estimating procedures that may not promote consistency and accuracy of costs over the project development process. The research proposes that a relationship exists between applying good estimating practices and minimizing cost escalation from the initial planning estimate to the engineer??s estimate at final design. The objective of this research is to develop a preliminary list of strategies, methods, and tools for project cost estimation practices aimed at achieving greater consistency and accuracy between the project development phases. A literature review was conducted that assisted in identifying factors that lead to the cost escalation of projects. The information from the literature was used to discover the core estimating assumptions that are the root causes behind cost escalation and lack of project estimate consistency and accuracy. After the cost escalation factors were determined, interviews with SHAs were conducted that lead to identifying unique and/or innovative approaches that will aid the SHAs in overcoming the cost escalation factors. The main methodology used to develop a potential list of strategies, methods, and tools was first focused on linking strategies to causes of cost escalation. Global strategies were identified by means of this approach. Methods and tools that would likely be effective in implementing the strategies are therefore directed at mitigating root causes of estimate problems in a focused approach. The strategies, methods, and tools are aligned with the project development phase where they would be implemented. Thus, a preliminary list of strategies, methods, and tools is provided in this study.Item Methods for Identifying Best-Value Bid for Performance-based Maintenance Contracts(2011-02-22) Ahmed, JubairPerformance-based contracting (PBC) for roadway maintenance is relatively new among various alternative contracting options available at present and is increasingly drawing more attention from state Departments of Transportation (DOTs) and the contracting community. Because performance-based maintenance contracts extend over multiple years (typically 5-7 years) and shift performance risk to contractors, it is critical that contractors be selected based on a form of best-value method rather than on the conventional low-bid method. Currently, highway agencies use various methods for determining the best-value bid based on cost and technical scores. Five best-value bid identification methods that are already in practice by the state transportation agencies in Florida, Virginia, North Carolina, United Kingdom, and New Zealand were used as case studies for this research. These five methods were evaluated in terms of the agency?s willingness to pay for quality and the neutrality of these methods with respect to lowest bid and highest quality. To understand and describe the bid evaluation method, the agency can develop a willingness to pay (WTP) curve. This curve should represent the agency?s needs and budget, reflect their project characteristics, and accommodate associated performance risks. An Excel macro based software tool has been developed that automates these five best-value bid identification methods and also helps customize anyone of these options for any agency.Item Optimal Incentive/Disincentive Determination Between Cost and Benefit(2013-08-08) Sharma, PiyushIn 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.Item Potential value extraction from TxDOT’s right of way and other property assets(2011-12) Paes, Thiago Mesquita; Prozzi, Jolanda; Caldas, Carlos H.Many Departments of Transportation (DOTs), including Texas Department of Transportation (TxDOT), have been challenged by inadequate funding from traditional federal and state fuel taxes, increasing construction cost, aging highway system, traffic congestions, and recent natural disasters, compromising their primary mission to provide safe vehicle transportation routes with adequate capacity. Furthermore, environmental awareness and sustainability concept have strengthened and sparked debates in Congress, culminating with several regulatory policies that affect, inclusively, transportation projects. This scenario has prompted DOTs to pursue innovative ways to reduce maintenance cost (at minimum) and generate revenue (at maximum) exploiting their assets, and to meet the new regulations. Likewise, the Center of Transportation Research at The University of Texas at Austin undertook a comprehensive research study to identify and determine when, where, and under what circumstances TxDOT should pursue the implementation of which Value Extraction Application (VEA), and how to effectively recognize and involve key stakeholders. As a result, 11 VEAs were identified. In addition, a methodological framework – embedding a multi-attribute criteria analysis matrix as the decision making method - was devised to guide TxDOT throughout the process of identifying, evaluating, comparing, and selecting the most appropriate VEA while a list of stakeholders associated with each VEA and a stakeholder analysis framework was provided to help TxDOT to identify and reach out key stakeholders.Item Quantifying the Effectiveness of Innovative Contracting Strategies on Schedule, Cost and Change Order(2013-08-01) Gaur, AnkitThe transportation infrastructure systems in the United States were built between the 50's and 80's, with 20 years design life. As most of them already exceeded their original life expectancy, State Transportation Agencies (STAs) are now under increased pressure to rebuild deteriorated transportation networks. Over the recent years, state transportation agencies (STAs) have taken into consideration various project delivery approaches apart from conventional project delivery approach to expedite project delivery. Since the introduction of these new alternative delivery approaches, not many substantial studies were conducted that evaluated the performance of these new alternatives. The absence of systematic studies about the effectiveness of these strategies and lack of appropriate analytical tools to evaluate them inhibits the STAs from budgeting precisely and accurately these strategies when they are deliberated for being put into practice. This study tries to address these limitations by evaluating the effectiveness of these strategies. The major objectives of this research were: 1) to evaluate the impact of contracting strategies on dealing with change orders 2) to evaluate the performance of different contracting strategies under varied work type for the state of Florida . For this research the study was conducted to quantify the changes to project duration and cost caused by change orders in the project under different contracting strategies and type of work. This was done through evaluating 2844 completed transportation infrastructure projects, completed between 2002 and 2011 in the state of Florida. These projects comprised of both the conventional projects and innovative alternative projects. The data was then statistically analyzed for evaluating the performance of these contracting strategies. The research concluded that alternative contracting strategies perform much better than conventional contracting in controlling project schedule but are found not to be as effective in controlling the project cost growth. The study also established that project size and work type affect the effectiveness of the contracting strategies. The study indicates that A+B is the worst performing contracting strategy among all the strategies evaluated. The results of this study will help the STAs to make better informed decision regarding selection of contracting strategy for project delivery.