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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.
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Bluetooth Data Collection System for Planning and Arterial Management
This report presents the results of a research and development project of an implementable portable wireless traffic data collection system. Utilizing Bluetooth wireless technology as a platform, portable battery powered data collection units housed in traffic barrels were developed. The use of these units is for short term data collection (normally up to one week) and can be deployed for travel time data collection, origin-destination study data collection, and intersection performance data collection. After design and development of the units, they were deployed in real applications of travel time data collection, origin-destination study data collection, and intersection performance data collection. The different applications are described in the report. A web-based application for processing the collected data was also developed. The report includes a user’s guide for the data collection units as well as a user’s guide for the web-based application.
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Transportation Performance Measures for Outcome Based System Management and Monitoring
The Oregon Department of Transportation (ODOT) is mature in its development and use of performance measures, however there was not a standard approach for selecting measures nor evaluating if existing ones were used to inform decision-making. This research report inventories ODOTs high-level performance measures, compares them to Federal, State, and Agency goals, identifies a framework to determine the suitability of performance measures and select new ones, and identifies new recommended measures. The outcomes of the project include a framework for evaluating and selecting measures, and recommended Key Performance Measures for the Agency.
Bridge Columns Constructed with Grade 80 Reinforcement
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Seismic Performance of Circular Reinforced Concrete Bridge Columns Constructed with Grade 80 Reinforcement
This project assessed the use of ASTM A706 Grade 80 reinforcing bars in reinforced concrete columns. Grade 80 is not currently allowed in reinforced concrete columns due to lack of information on the material characteristics and column performance. Six half-scale, circular columns were tested: three constructed with Grade 60 reinforcement and three constructed with Grade 80 reinforcement. Designs followed standard design methodologies used by State Highway Agencies (including AASHTO). Results indicate that columns constructed with Grade 80 reinforcement performed similar to columns constructed with conventional ASTM A706 Grade 60 reinforcement. Computational modeling was performed using OpenSees for all six columns. Results indicate that the columns constructed with Grade 80 reinforcement achieved similar resistance and displacement and curvature ductility values when compared with the reference columns constructed with Grade 60 reinforcement. The columns constructed with Grade 60 reinforcement showed larger hysteretic energy dissipation than the columns constructed with Grade 80 reinforcement.
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The Use of Synthetic Blended Fibers to Reduce Cracking Risk in High Performance Concrete
The aim of this project was to investigate a relatively new technique to control early-age cracking; the use of blended size polypropylene fibers in high performance concrete mixtures. The key findings from this work were that the use of drying shrinkage test methods alone, without the capture of cracking risk, showed that the inclusion of fibers did not reduce drying shrinkage in unrestrained specimens. However, in restrained testing (where the possibility of crack formation is promoted) the fibers were able to 1) reduce the rate of stress generation in specimens 2) prolong the time to cracking in the restrained ring test (ASTM C 1581) and 3) reduce the crack widths and the growth of cracks once cracking did initiate. As a result the use of blended fibers in high performance concrete points to another viable solution for reducing the risk of cracking in service.
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Safe and Effective Speed Reductions for Freeway Work Zones Phase 2
Freeway preservation projects typically require construction workers to conduct their work in close proximity to ongoing traffic and often reduce traffic flow to a single lane while work is undertaken in an adjacent lane. Due to the short-term nature of these work zones, temporary traffic control measures typically consist of a line of cones, blocker vehicles, and impact attenuators. Work zones place both the workers and passing motorists at risk of injury. The Oregon Department of Transportation conducted a research study to investigate the impact of selected traffic control devices on vehicle speeds within highway paving project work zones. The research study, which follows a similar study conducted a year earlier, centered around two case studies on multi-lane paving projects in Oregon. On each case study, the researchers implemented combinations of multiple traffic control devices (“Speed 50” signs, PCMS signs, and radar speed displays) and evaluated their impact on vehicle speed. The research findings suggest using a combination of reduced speed limit signs, radar speed monitoring displays, and PCMS signs on either trailers or rollers. The results of the present study complement those of the prior study and, combined with the prior study, provide ODOT with guidance on the selection of traffic control measures for freeway preservation projects.
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Cathodic Protection Evaluation
This research investigates the effectiveness of a new corrosion rate test instrument in making field evaluations of the corrosion condition of several conventionally reinforced concrete coastal bridges. The instrument is the Gecor 9 Corrosion Rate Meter and comes with several sensors. This device is able to perform several techniques to evaluate the corrosion activity of steel reinforcement under diverse conditions. The Gecor’s Sensor A is equipped with three reference electrodes (RE), 1 counter electrode (CE), and 1 guard electrode (GE). Sensor A was used to measure the rebar corrosion current, icorr, using a DC galvanostatic pulse with modulated applied current confinement. This procedure was used to obtain baseline data for 21 zones of an impressed current cathodic protection (ICCP) system recently installed on the Conde McCullough Bridge in Coos Bay. That same procedure was also used to evaluate the reinforcement corrosion activity at two failed ICCP zones at the Yaquina Bay Bridge. Both of those ICCP systems utilized thermally sprayed zinc as distributed anodes. Sensor A is also able to perform an AC-based test to qualitatively evaluate the effectiveness of cathodic protection (CP) systems without the need to interrupt the applied CP current. That test protocol was applied to the same 21 ICCP zones at the Coos Bay Bridge and to six test location of the Lint Creek Bridge that has a galvanic anode CP (GACP) system installed to control rebar corrosion. Gecor Sensor B is equipped with one RE and one CE and is used to concurrently measure a rebar’s corrosion potential, Ecorr, and the resistivity of the surrounding concrete. Firmware in the Gecor 9 uses the observed corrosion potential and concrete resistivity to state the corrosion risk for the steel at the location tested. In general, the Gecor 9 performed very well. However, although it is a sophisticated instrument, it is able to produce data that is clearly questionable. Fortunately, since the Gecor has the ability to perform several markedly different types of tests, inconsistencies are generally obvious and a suspicious reading can be re-tested. Measurement errors were less a problem on the Yaquina Bay and Lint Creek Bridges because rebar could be clearly located before testing. At Coos Bay, the presence of a new zinc coating interfered with being able to identify rebar locations prior to removing the zinc on the concrete surface. At locations where reference electrodes were present and in areas of rebar structure bonds, a reasonable estimation of the rebar location could be made prior to removal of the zinc anode over an area of 8-9 inches in diameter to allow testing with the Gecor. Generally speaking, the Gecor 9 was able to make reasonable evaluations of cathodically protected rebar without having to interrupt the CP system. In terms of CP operation, this research demonstrated that: 1) the GACP system at Lint Creek is working well and protecting the embedded rebar; 2) All 12 locations tested in the two failed CP zones at Yaquina Bay reflect passive behavior of the embedded rebar even after the CP current had been interrupted for a number of years; Although the Gecor performance at Coos Bay was not as consistent as observed at the other bridges, it appears for future application, if rebars at test locations were located prior to applying the zinc coating, the test could be conducted with the sensor in proper alignment with the embedded steel, and that would significantly improve the performance of the instrument.
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Understanding and Mitigating Effects of Chloride Deicer Exposure on Concrete
Field and laboratory investigations were conducted to examine the effects of chloride deicers on concrete bridge decks and to identify and evaluate best practices and products to mitigate such effects. The concrete bridge decks exposed to KAc or MgCl2 deicer showed significant reductions in their compressive strength, splitting tensile strength and microhardness, whereas those exposed to NaCl deicer and without signs of surface distress did not. Visual inspection would be misleading for assessing the condition of concrete bridge decks exposed to MgCl2 deicer, as the chemical attack by MgCl2 generally does not exhibit apparent signs of distress. Chloride penetration as low as 0.1 in (2.5 mm) based on AgNO3 spray method does not guarantee the integrity of the concrete exposed to MgCl2 deicer. At least half of cored ODOT bridge decks exhibited air void spacing factor higher than 200 microns (0.008 inches) per the ASTM C457 test method, indicating that they no longer have a proper air-void system for freeze-thaw resistance. The role of MgCl2 in the carbonation and ASR of field concrete, if any, is not significant, but KAc may play a significant role in contributing to ASR in concrete containing reactive aggregate. The microscopic evidence further suggests that the concrete in the field environment had been affected by both physical and chemical degradation by the joint action of freeze-thaw cycles and MgCl2. A set of mortar samples can be deployed to assess the cumulative MgCl2 exposure at a given site. A simplistic empirical-mechanistic model was developed to evaluate the conditions of the current bridge decks. Surface treatments, especially penetrating sealers and water repellents should be used to protect new concrete and existing concrete without too much chloride contamination. For any surface treatment to be used, it is important to select products with high resistance to both gas and water penetration to maximize the concrete’s resistance to “salt scaling”. When the concrete surface has deteriorated to a more severe degree, overlays should be used. For concrete decks exposed to freeze-thaw and wet-dry cycles and both NaCl and MgCl2 deicers, silica fume modified cementitious overlays and micro-fiber modified cementitious overlays should be used. For decks mainly exposed to MgCl2 deicer, Castek T48 polymer overlay is a good candidate. For areas that are also subjected to studded tires and high risk of abrasion, Castek T48 and KwikBond PPC-1121 polymer overlays should be used instead of cementitious overlays.
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Review of Studded Tires in Oregon
This study provides an update to the previous studded tire study for Oregon completed in 2000. The
focus of this research was to quantify current use of studded tires and the wear and cost caused by that use. Some results include a decline in studded tire use from about 16 percent of registered
vehicles in 1995 to about 4 percent in the 2013-14 winter season. A wear rate for PCC is about
0.0091 inches per 100,000 studded tire passes, while the wear rate of asphalt pavement is about
0.0295 inches per 100,000 studded tire passes.
Three different cost categories of studded tire damage mitigation were identified. The three scenarios
are included in this study, but the base case scenario for these estimates predicts an annual average
expenditure of about $4 million from the year 2012 up to the year 2022. These estimates are only for
the State Highway System and exclusive of any amounts to be spent by the cities and counties on their road systems.