Transportation Construction Work-Zone Safety Impact on Time-Related Incentive Contracting Projects

Work-zone safety on highway projects continues to be a national concern, and project safety performance is one of the indicators of project success. Many contractors and State Transportation Agencies believe that expedited construction time under incentive contracting contributes to reducing the safety risk of road users traveling through work zones. However, the truth of this belief has never been measured or supported by any statistical evidence. Therefore, this research investigates the statistical relationship between time-related incentive road construction projects and frequency of vehicle crashes in California to understand the impact of time-related incentive provisions on project safety performance. The research team collected incentive and non-incentive project data from the California Department of Transportation. Additionally, vehicle crash data was collected from the California Statewide Integrated Traffic Records System. Using Geographic Information System (GIS) software, the locations of construction projects and crashes at the project locations were then pinpointed on GIS centerline layers. The research team performed statistical analyses to test the relationship between the frequency and characteristics of crashes at incentive project sites and ones at non-incentive project sites before, during, and after construction. Finally, the analysis results for both time-related incentive projects and non-incentive projects were summarized to provide project planners and managers with a better understanding of the impact of time-related incentive contracting on project safety performance

Improving Transportation Construction Project Performance: Development of a Model to Support the Decision-Making Process for Incentive/Disincentive Construction Projects, MTI Report 09-07

This research presents a project time and cost performance simulation model to assist project planners and managers by providing a complete picture during the Incentive/Disincentive (I/D) contracting decision-making process of possible performance outcomes with probabilities based on historical data. This study was performed by collecting transportation construction project data. The collected project data from the Florida Department of Transportation were evaluated using time and cost performance indices and then statistical data analysis was performed to identify important factors that influence construction project time performance. Using Monte Carlo simulation procedures, this study demonstrated a methodology for developing an I/D project time and cost performance prediction model. User-friendly visual interfaces were developed to perform the simulation and report results using Visual Basic Application programming. The developed model was validated using additional cases of transportation construction projects. Based on statistical analysis, this research found that several project factors influence I/D contracting performance. The important factors that had significant impacts on project performance were the effects of contract type, project type, district, project size, project length, maximum incentive amount, and daily I/D amount. In conclusion, the developed model applied to I/D contracting projects will be a useful tool to assist the project planners and managers during the decision-making process and will promote the efficient use of I/D contracting, which will benefit the traveling public by saving their travel time from construction delays. With additional project data, the developed model can be updated easily and the more data used for the model, the better the accuracy of prediction that can be expected

Analyzing the Potential of Hybrid and Electric Off-Road Equipment in Reducing Carbon Emissions from Construction Industries

This report quantifies the likely impact recent improvements in emissions technology in the heavy construction equipment fleet will have on national and state-level carbon emissions from construction industries. Specific technologies examined in this report include hybrid and electric-powered off-road equipment. Innovation in the equipment manufacturing industry, and adoption of innovative technology by construction firms, is driven by a wide range of factors, some of which can be influenced by public policy. Therefore, this paper describes policies available to public decision makers at the local, state and national levels that impact equipment use and development decisions, including those that encourage the use of green equipment in government procurement, local level job site emissions regulations, and state and nationally mandated emissions standards, fuel taxes, and direct research subsidies

Systematic Procedures to Determine Incentive / Disincentive Dollar Amounts for Highway Transportation Construction Projects, Research Report 11-22

The Federal Highway Administration has encouraged state transportation agencies to implement Incentive/Disincentive (I/D) contracting provisions for early project completion. Although general guidelines to determine the I/D dollar amount for a project are available, there is no systematic and practical tool in use to determine optimum I/D dollar amounts for I/D projects considering road user cost, agency cost, contractor’s acceleration cost, and contractor’s cost savings. Therefore, systematic procedures and models to assist project planners and engineers in determining an appropriate I/D dollar amount are essential to optimizing the use of I/D contracting techniques. This research performed a literature review related to the determination of daily I/D dollar amounts. Caltrans I/D project data were then collected and evaluated. Project performance data were analyzed with regard to project outcomes in two key areas: project time and project cost. Statistical analyses were performed to identify the impact of I/D dollar amount on project time and cost performance. Using Construction Analysis for Pavement Rehabilitation Strategies (CA4PRS) software, Caltrans I/D projects were analyzed to introduce three different levels of CA4PRS implementations for the I/D dollar amounts calculation. Based on the results of the I/D project case studies, the systematic procedures to determine appropriate I/D dollar amounts were developed using the CA4PRS schedule-traffic-cost integration process for the new I-5 rehabilitation project in LA. The proposed procedures were applied to a typical highway pavement rehabilitation project using HMA (hot mix asphalt) materials. Further research is needed to apply the proposed model to other types of highway projects, with adjustment for the type of project

Trend Analysis of Long Tunnels Worldwide

High-speed rail construction projects have frequently required long tunnels to reduce travel time and distance. The California High-Speed Rail (CHSR) authority is considering a tunnel up to 16 miles long for a direct route from Palmdale to Burbank. With advances in tunneling technology, the many long tunnels in use around the world today hold valuable lessons for CHSR, particularly with respect to minimization of ground disturbance and improved passenger and operator safety. The primary objective of this project is to determine the state of the art for construction and operation of long tunnels used for high-speed rail. With an abundance of long tunnels successfully completed and already in use around the globe, an examination of those projects can provide the State with the benefit of their experience at little cost. The research began with a review of the literature on long tunnels around the world, with a focus on characteristics and the research team constructed a detailed database of information on the projects behind the world’s long tunnels. Based on the data, this report presents data on 67 tunnels longer than 4.5 miles, including 32 high-speed railway tunnels, located in 28 countries around the world. The research team analyzed the data to determine the factors that should be considered in planning long tunnels for HSR projects. Analysis results were documented in a systematic manner to compare with potential tunnels for the Palmdale-to-Burbank segment of the California HSR system. It is hoped that the trends identified from the aggregate data will help inform decisions for the tunnel projects being considered for the Palmdale-to-Burbank segment of California High-Speed Rail

Effectiveness Study On Temporary Pavement Marking Removals Methods

This study was conducted to identify effective temporary marking removal methods and procedures on concrete and asphalt pavements. Pavement markings provide guidance to road travelers and can lead to accidents when not properly removed. Current state guidelines on removal do not provide clear and objective methods of measurement. After testing the most common removal methods, this research concluded that removing markings by chemical was not only cost and results-oriented effective compared to other methods, but it was also safe to the environment and road users. Finally, a baseline of measurements was developed by the research team for this project, along with the feasibility of using digital image processing to objectively determine whether or not a removal method could be deemed effective

Effectiveness Study On Temporary Pavement Marking Removals Methods

This study was conducted to identify effective temporary marking removal methods and procedures on concrete and asphalt pavements. Pavement markings provide guidance to road travelers and can lead to accidents when not properly removed. Current state guidelines on removal do not provide clear and objective methods of measurement. After testing the most common removal methods, this research concluded that removing markings by chemical was not only cost and results-oriented effective compared to other methods, but it was also safe to the environment and road users. Finally, a baseline of measurements was developed by the research team for this project, along with the feasibility of using digital image processing to objectively determine whether or not a removal method could be deemed effective

Cost Estimate Modeling of Transportation Management Plans for Highway Projects, Research Report 11-24

Highway rehabilitation and reconstruction projects frequently cause road congestion and increase safety concerns while limiting access for road users. State Transportation Agencies (STAs) are challenged to find safer and more efficient ways to renew deteriorating roadways in urban areas. To better address the work zone issues, the Federal Highway Administration published updates to the Work Zone Safety and Mobility Rule. All state and local governments receiving federal aid funding were required to comply with the provisions of the rule no later than October 12, 2007. One of the rule’s major elements is to develop and implement Transportation Management Plans (TMPs). Using well-developed TMP strategies, work zone safety and mobility can be enhanced while road user costs can be minimized. The cost of a TMP for a road project is generally considered a high-cost item and, therefore, must be quantified. However, no tools or systematic modeling methods are available to assist agency engineers with TMP cost estimating. This research included reviewing TMP reports for recent Caltrans projects regarding state-of-the-art TMP practices and input from the district TMP traffic engineers. The researchers collected Caltrans highway project data regarding TMP cost estimating. Then, using Construction Analysis for Pavement Rehabilitation Strategies (CA4PRS) software, the researchers performed case studies. Based on the CA4PRS outcomes of the case studies, a TMP strategy selection and cost estimate (STELCE) model for Caltrans highway projects was proposed. To validate the proposed model, the research demonstrated an application for selecting TMP strategies and estimating TMP costs. Regarding the model’s limitation, the proposed TMP STELCE model was developed based on Caltrans TMP practices and strategies. Therefore, other STAs might require adjustments and modifications, reflecting their TMP processes, before adopting this model. Finally, the authors recommended that a more detailed step-by-step TMP strategy selection and cost estimate process be included in the TMP guidelines to improve the accuracy of TMP cost estimates

Coarsening model of cavity nucleation and thin film delamination from single-crystal BaTiO3 with proton implantation

The layer splitting mechanism of a proton implanted single crystal ferroelectric BaTiO3 thin film layer from its bulk BaTiO3 substrate has been investigated. The single crystal BaTiO3 thin film layer splits as the hydrogen gas diffuses and the internal cavity pressure increases. Ripening mechanism driven by the pressurized hydrogen in the implantation-induced damage zone makes coarsening of the cavities and causes the delamination of the thin layer during the annealing. A unique criterion relation of blister nucleation and evolution has been derived and a simplified debonding criterion is proposed in terms of dimensionless parameters based on the force equilibrium condition. A numerical simulation of two-bubble evolution and delamination of thin film is performed using a finite element method

Construction cost estimation using a case-based reasoning hybrid genetic algorithm based on local search method

Estimates of project costs in the early stages of a construction project have a significant impact on the operator\u27s decision-making in essential matters, such as the site\u27s decision or the construction period. However, it is not easy to carry out the initial stage with confidence, because information such as design books and specifications is not available. In previous studies, case-based reasoning (CBR) is used to estimate initial construction costs, and genetic algorithms are used to calculate the weight of the retrieve phase in CBR\u27s process. However, it is difficult to draw a better solution than the current one, because existing genetic algorithms use random numbers. To overcome these limitations, we reflect correlation numbers in the genetic algorithms by using the method of local search. Then, we determine the weights using a hybrid genetic algorithm that combines local search and genetic algorithms. A case-based reasoning model was developed using a hybrid genetic algorithm. Then, the model was verified with construction cost data that were not used for the development of the model. As a result, it was found that the hybrid genetic algorithm and case-based reasoning applied with the local search performed better than the existing solution. The detail mean error value was found to be 3.52%, 6.15%, and 0.33% higher for each case than the previous one