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Operational Guidance for Bicycle-Specific Traffic Signals in the United States
The research consisted of two phases: 1) a synthesis of practice and 2) and analysis of cyclist performance characteristics. The synthesis of current practice reviewed the literature, current engineering design and operational guidance documents, and surveyed the jurisdictions about their current deployments of bicycle-specific signals. This report summarizes research of cyclist behavior at signalized intersections in Portland, Eugene, Corvallis, Beaverton and Clackamas County, OR. These signals had both bicycle-specific indications and vehicle-only signals. A total of 4,673 cyclists were observed. For each cyclist observed arriving on red, a set of descriptive variables were collected (e.g., age, sex, helmet use, presence of cargo, arrival in group). Time-based event data were collected to establish reaction times, crossing times, waiting time, gap acceptance, and saturation flow rates. Compliance behavior was also established for these cyclists.
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Criteria for the Selection and Application of Advanced Traffic Signal Systems
The Oregon Department of Transportation (ODOT) has recently begun changing their standard traffic signal control systems from the 170 controller running the Wapiti W4IKS firmware to 2070 controllers operating the Northwest Signal Supply Corporation’s Voyage software. Concurrent with this change in standard signal control systems, ODOT has taken the opportunity to install test sites with adaptive signal control systems and evaluate advanced features in the Voyage software.
The evaluation of advanced features and adaptive signal control systems has led to a series of questions about how to measure performance, when to apply a given feature, and when should one system be preferred over another. To answer these questions a survey of literature and practicing professionals was conducted to determine the current state of the practice regarding conventional and adaptive signal control systems. The survey of practitioners indicated that practitioners in general were seeking answers regarding when and how to implement adaptive systems. To assist ODOT’s engineers in selecting when and which systems to evaluate more closely, a methodology frame work has been developed and implemented in a Microsoft Excel based evaluation tool. This framework uses queuing models and simplified control logic to estimate corridor performance. Selected additional features have also been enabled to allow engineers to evaluate the performance benefits that may be realized through enabling them with the existing systems.
Finally, to compare performance across different systems and different measures of effectiveness, the research team implemented a cost to benefit ratio calculation. This calculation encompasses performance measures produced by the evaluation model as well as external data regarding existing equipment, required upgrades, and additional costs such as those associated with retiming operations. By including as many cost factors as practical, the methodological framework and its Excel-based implementation may offer a means to make the selection of systems to evaluate as simple and straightforward as possible.
Analysis and Design of Pipe Ramming Installations
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Analysis and Design of Pipe Ramming Installations
The trenchless technology known as pipe ramming for construction of culverts and buried pipes under roadways or other infrastructure has gained significant popularity due to its cost-effectiveness and ability to alleviate surface disruptions associated with open-cut trenching. Although the experience with pipe ramming is increasing, there has been remarkably little technical guidance available for engineers to appropriately specify aspects of a pipeline or culvert installation, including the planning of feasible layouts, rates of penetration, pipe diameters, and hammers. This research provides a comprehensive engineering framework for evaluation of culvert installations at the planning phase to address the gaps in knowledge associated with pipe ramming.
Presently there are no existing and proven techniques for prediction of settlement, vibration, driving stresses, soil resistance to ramming, and drivability for pipe ramming installations. This study has adopted existing drivability, soil resistance, settlement, and vibration prediction models from pipe jacking, microtunneling, and pile driving models and examined their applicability in pipe ramming installations, resulting in new and technology-specific design guidance. The development of this comprehensive engineering guidance is based on engineering calculations empirically tuned using a database of actual performance measurements. Field observations of five productions installations and a full-scale experiment were conducted to form the performance database employed to understand the mechanics associated with pipe ramming installations, ranging from vertical ground movements, ground vibrations, and installation performance.
Settlement prediction was evaluated using the inverted normal probability distribution based models, and these methods overestimated the observed settlements close to the center of the pipes and under-estimated settlements at radial distances away from the pipe. A pipe-ramming-specific hyperbolic model was developed for better prediction of the vertical settlement induced by pipe ramming in granular soils. Attenuation of observed pipe ramming-induced vibrations was modeled using a simple semi-empirical approach, and the calibrated model resulted in reasonable predictions of the ground vibrations for granular soils. The static soil resistance to ramming was evaluated using the traditional quasi-static pipe jacking models and the models resulted in inaccurate predictions for instrumented pipe ramming installations. Therefore pipe ramming-specific static soil resistance models were developed for both the face and casing resistance in granular soils. Principles of stress wave theory routinely applied in the drivability analyses for pipe foundations were adopted for the evaluation of the dynamic response of pipes during ramming. Reliable estimates of the static soil resistance and dynamic soil parameters were obtained through signal matching processes. Date-informed drivability analysis were performed to simulate the magnitude of driving stresses and develop drivability curves which relate the penetration resistance of a given pipe and hammer to the range of static soil resistances. The study culminates in the first comprehensive framework and recommendations for the installation of pipes by ramming, and should help owners, consultants, and contractors to appropriately plan pipe ramming installations.
Development of Shrinkage Limits and Testing Protocols
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Development of Shrinkage Limits and Testing Protocols for ODOT High Performance Concrete
ODOT has observed varying degrees of cracking in their concrete structures. Cracking of high performance reinforced concrete structures, in particular bridge decks, is of paramount concern to ODOT. Cracking at early ages (especially within the first year after placement) results in additional costs and a significant maintenance burden to ODOT. The causes behind cracking in high performance concrete are well known and documented in the existing literature. However, appropriate shrinkage limits and standard laboratory/field tests that allow proper criteria to ensure crack-free or highly cracking-resistant high performance concrete are not clearly established either in the technical literature or in specifications. The purpose of this research was to provide shrinkage threshold limits for specifications and to provide a robust test procedure that allows easy determination of compliance with specified threshold limits. It has been shown that the “restrained ring” tests are the most comprehensive accelerated laboratory tests to accurately identify cracking potential. In addition, acceptable correlation between the ring test and the field test has been observed and documented. However, a simplified yet robust test procedure is in demand from materials suppliers and Departments of Transportation. Analysis of data obtained from this research project showed that the ratio of free shrinkage to shrinkage capacity (theoretical strain related to tensile strength and modulus of elasticity), referred to as a cracking potential indicator (CPI), was a promising assessment of cracking resistant performance. In this way, only the free shrinkage test (ASTM C157) and basic mechanical properties (ASTM C39, C469 and C496) are required to assess cracking risk of candidate high performance concrete mixture designs. This research investigation showed that a CPI less than 3.0 indicated low cracking risk when correlated to standard restrained ring tests. For ODOT HPC concrete bridge deck mixtures, a limit of 450 microstrain for free shrinkage at 28 day from initiation of drying is recommended to achieve satisfactory cracking resistance. Correlation to field experience is also recommended if these recommended thresholds/limits are adopted by ODOT.
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Multimodal Freight Project Prioritization
As available data has increased and as the national transportation funding bills have moved toward objective evaluation, departments of transportation (DOTs) throughout the country have begun to develop tools to measure the impacts of different projects. Increasingly, DOTs recognize the freight transportation system is necessarily multimodal. However, few DOTs have clearly stated objective tools to make multimodal freight project comparisons. This report informs that gap by summarizing the existing academic literature on the state of the science for freight project impact estimation and reviewing methods currently used by select DOTs nationwide. These methods are analyzed to identify common themes and determine potential avenues for multimodal project evaluation. Most methods either take the form of benefit-cost analysis or a scorecard approach. Examples of each were reviewed in-depth and patterns evaluated. While most tools use similar measures, the supporting metrics vary widely and are not applicable to all modes.
Proof of Concept: GTFS Data as a Basis for Optimization - Transit Networks
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Proof of Concept: GTFS Data as a Basis for Optimization of Oregon’s Regional and Statewide Transit Networks
Assessing the current "state of health" of individual transit networks is a fundamental part of studies aimed at planning changes and/or upgrades to the transportation network serving a region. To be able to effect changes that benefit both the individual transit networks as well as the larger transportation system, organizations need to develop meaningful strategies guided by specific performance metrics. A fundamental requirement for the development of these performance metrics is the availability of accurate data regarding transit networks.
Prior to 2005, transit data was not readily available. This situation complicated the assessment of single transit networks, let alone performing a state-wide or region-wide study. The advent of the General Transit Feed Specification (GTFS) changed this constrained landscape and motivated transit operators to release their schedules and route information to third party developers.
In this report, the development work conducted to create an open source software tool to help the Oregon Department of Transportation's Public Transit Division gain a better understanding and more efficient utilization of existing state-wide transit networks is described. The final product, referred to as the Transit Network Analysis software tool, incorporates GTFS data and census data as its main inputs and can be used to visualize, analyze and report on the Oregon transit network.
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Underwater Acoustic Noise Generation and Propagation Resulting from Pile Driving for Oregon Bridge Construction
There is growing concern about noise levels from pile driving activities associated with the construction of highway bridges and other in-water structures. It has been demonstrated that noise generated from pile driving with an impact hammer can be harmful to aquatic species protected by the state and federal Endangered Species Act (ESA). To comply with current environmental regulations and noise level attenuation criteria, ODOT needs to develop hydro-acoustic monitoring protocol and predictive models so projects can develop appropriate sound attenuation strategies based on site specific conditions.
This research project addresses several concerns related to hydro-acoustic impacts and will ultimately help highway projects stay in compliance with established noise level criteria. The research project included: 1) identification of sound generation mechanisms from pile driving and how sound propagates into the surrounding underwater environment, 2) development of an acoustic monitoring procedure and predictive model that will help assure compliance and 3) validation and verification of predictive models.
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Comparison of Pelletized Lime with Other Anti-Stripping Additives
Stripping is a common problem in HMA pavements in Oregon, especially in Eastern Oregon.
Stripping is the degradation of the bond between the aggregate and the asphalt binder due to the
presence of water – this mechanism of degradation can lead to loss of capacity and cracking in the
pavement. A common additive used in the industry to mitigate stripping damage is powdered lime.
However, challenges with air-borne powdered lime have SHAs investigating alternatives to powdered
lime. The purpose of this study was to determine the effectiveness of potential alternatives to
powdered lime additive in preventing stripping.
This research evaluated the moisture susceptibility of five anti-stripping additives with three separate
aggregates. The aggregates exhibited a range of potential stripping from not susceptible to susceptible.
Results indicate that Aggregates 1 and 3 are likely susceptible to stripping, with Aggregate 3 likely
being the most susceptible. Powdered lime increased the TSR and ECS ratios for the susceptible
aggregates. Mixtures with Additive 4 exhibited similar performance to mixes containing powdered
lime. Additive 2 exhibited improved performance compared to the control but TSR and ECS ratios
were lower than the specimens with powdered lime. Results from mixtures with Additive 3 exhibited
limited improvements in TSR and ECS ratios. Additives 4 and 2 should be considered for future use in
HMA when stripping could be an issue.
One practice in ODOT is to inlay HMA pavements 15 years after construction. If the pavement is
exhibiting damage resulting from stripping, the inlay can be specified to be 4 inches (102 mm) deep. If
the pavement is not exhibiting damage from stripping, the inlay can be specified at 2 inches (51 mm)
deep. Using this information, an economic analysis was performed. Other options are available but
these were not included in the analysis. The economic analysis indicates that when a reduction in inlay
thickness is realized, there is significant value in using additives. The sensitivity analyses indicated
that large changes in the input variables do not make the cost of using additive cost ineffective – that
is, there is significant value in using additives even when input variables (rate of return, number of
future inlays, inlay depth, cost of inlay HMA, original construction cost, and additive cost) change
Pedestrian and Bicycle-Specific Data Collection
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Design and Implementation of Pedestrian and Bicycle-Specific Data Collection Methods in Oregon
Although there is a growing need to access accurate and reliable pedestrian and bicycle data, there is no statewide system to collect data or plan future data collection efforts in the state of Oregon. To address these issues this research conducted a comprehensive review of pedestrian and bicycle data collection methods and counting technologies. Oregon data sources were also compiled and AADT estimation techniques were reviewed and applied to Oregon data. A pilot study was conducted to test bicycle and pedestrian counting methods at signalized intersections with 2070 controllers. The report also provides a summary of recommendations regarding factoring methods and the implementation of a statewide non-motorized data collection system.