Institutional Options for VMT Data and Fee Collection Centers
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The objective of this report is an analysis of public vs. private data and fee collection centers for vehicle miles traveled (VMT) fees. This includes the identification and evaluation of issues that will affect the relative desirability of the two forms of ownership and operation. These issues include cost, enforcement, debt collection, flexibility, and public perception. The report reviews the literature on these topics and tries to identify differences across possible institutional arrangements with respect to these topics.
Data Transmission Options for VMT Data and Fee Collection Centers
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The Oregon Road User Fee Task Force (RUFTF) is charged with developing a design for revenue collection for Oregon’s roads and highways that will replace the current system for revenue collection for all light vehicles in the state. One option under consideration is the collection of fees for vehicle miles traveled (VMT). The objectives of this report are to analyze data transmission options and provide cost estimates for VMT data and fee collection centers. This includes development of frameworks and cost estimates for mileage-based fee collection centers, including the identification of issues related to data transmission, data collection, fee collection, data processing, billing, and payment, including pre-payment options. Trade-offs have been identified and the issues related to the trade-offs have been addressed. A companion study entitled Institutional Options for VMT Data and Fee Collection Centers has examined issues related to public/private operation of fee collection centers.
Assessment and Mitigation of Liquefaction Hazards to Bridge Approach Embankments in Oregon
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The seismic performance of bridge structures and appurtenant components (i.e., approach spans, abutments and foundations) has been well documented following recent earthquakes worldwide. This experience demonstrates that bridges are highly vulnerable to earthquake-induced damages and loss of serviceability. These damages are commonly due to soil liquefaction and the associated impact of ground failures on abutments and pile foundations.
Current design methods for evaluating permanent, seismically-induced deformations of earth structures are based on rigid body, limit equilibrium and “sliding-block” procedures that are poorly suited for modeling soil liquefaction and establishing the pattern of embankment-abutment-foundation deformations. Recent advances in the seismic design of bridges have addressed some of the limitations of the current design procedures; however practice-oriented methods for estimating permanent deformations at sites that contain liquefiable soils and/or where soil improvement strategies have been employed to mitigate liquefaction hazards are still at an early stage of development. In Oregon, the evaluation of soil liquefaction and abutment performance are complicated by the rather unique seismo-tectonic setting and the prevalence of silty soils along the primary transportation corridors in the Portland/Willamette Valley region and along the Columbia River.
This study has focused on numerical dynamic, effective stress modeling to determine the seismic performance of sloping abutments and the effectiveness of soil improvement for reducing permanent ground deformations. Recommendations are provided for evaluating the dynamic behavior of regional silty soils, the application of soil improvement at bridge sites, and comparisons have been made between the deformations computed using the advanced numerical model and the rigid-block methods used in practice. The results have been presented in the form of design charts, where possible, that can be readily used by design engineers in preliminary design and incorporated into the ODOT Liquefaction Mitigation Policy. This study has demonstrated the utility, and limitations, of soil improvement solely by densification techniques. In some cases soil densification techniques for mitigating seismic hazards may not be adequate in limiting deformations to allowable limits, indicating that other methods of soil improvement (e.g., cementation, stone columns, drainage) or structural improvements may also be required.
Improving the Effectiveness of Partnering
The objectives of the research was to: (1) assess the current state of the Oregon Department of Transportation’s (ODOT) partnering program; (2) examine ways for improving current processes; and (3) recommend process improvements and possible new methods and practices that could be used to increase the effectiveness of partnering. The research consisted of a literature review, survey of state departments of transportation, a survey of ODOT and Contractor personnel, and case studies of 12 recently completed ODOT partnered projects.
The survey of ODOT and contractor personnel showed that the majority of respondents feel that partnering improves communication, trust, and teamwork. Most also believe the goals and values created in the initial partnering workshop are carried out in the field. The survey also showed that contractors, more so than ODOT personnel, feel that partnering helps improve quality, decision making, and schedule adherence, as well as reducing the size and number of claims. The case studies of seven successfully partnered projects revealed specific critical success factors associated with the successful projects. Conversely, the case studies of five unsuccessfully partnered projects exposed challenges inhibiting partnering success.
Based on the research findings from the literature review, surveys and case studies, recommendations were made to improve ODOT’s program. One of the recommendations included additional training for partnering participants, to be jointly sponsored by ODOT, and the Associated General Contractors of Oregon. Another recommendation called for ongoing facilitation throughout a partnered project.
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Aggregate Resource Inventory and Needs Forecast Study
The study identified and inventoried ODOT-owned owned and leased aggregate sites, assessing the quality and estimated quantity of material. In addition, an aggregate needs forecast was prepared, projecting that 60,801,320 Mg of aggregate will be required for paving projects, bridge rehabilitation and reconstruction, OTIA modernization projects, and maintenance needs over the next 15 years.
A comparison was made between the 15-year forecast and the estimated reserve from potentially significant and/or key sites for each District. In seven of the Districts, the estimated reserve exceeds the forecast need. However, in the other eight districts the need exceeds the reserve. In Districts 2B, 3,5,11, and 13 the estimated reserve is significantly less than the forecast demand.
Estimated reserves were based on field calculations. This study considered only sources of high quality rock suitable as base rock, paving and reinforced concrete structures, and did not address ODOT needs for sand and lower quality fill materials. In addition, the study did not determine whether or not a site is actually usable. A closer look at the distribution of sites and reserves in the study shows that some areas of the state are resource poor, and locations of large reserves do not necessarily match with the areas of highest projected need.
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For state owned or leased aggregate sites considered potentially significant or otherwise strategically important, ODOT should develop a program to protect those sites from future incompatible adjacent land uses. This would include submitting a Post-Acknowledgment Plan Amendment (PAPA) application to the local governments having jurisdiction over the sites.
Field Verification Process for Open-Graded HMAC Mixes
The State of Oregon uses significant amounts of open-graded HMAC mixes as primary wearing courses on state highways. The primary materials design system for these mixes relies heavily on laboratory draindown to select the design asphalt content. Subsequent adjustments in the field rely heavily on the visual draindown characteristics as well. Draindown is a limiting characteristic in terms of constructability of open-graded mixes, but adjustments made to mitigate draindown may reduce the long-term performance of the wearing surface.
This research looked at the viability of using conventional film thickness measurements as a means of field verifying the quality of the open-graded mixtures being produced. The findings were that conventional film thickness measurements were too sensitive to the material passing the 75 mm sieve and were therefore not a practical tool.
The authors proposed a simple alternative involving measuring the volume change that occurs when asphalt cement is added to uncoated aggregate. This measurement tool uses readily available field laboratory equipment and provides a simple means of measuring a fundamental mixture property.
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Assessing Public Inconvenience in Highway Work Zones
The traveling public is making increasingly frequent contact with the Oregon Department of Transportation (ODOT) when entering a work zone. Because ODOT remains very sensitive to the needs of the public, it is important to understand their opinions and values. The objective of this research was to conduct a series of focus groups and surveys to investigate highway users’ views and their priorities relating to highway work zones. ODOT conducted six focus groups with motorists, school bus drivers, fire and emergency vehicle operators, business owners, and truck drivers. From the focus group results, two surveys were developed and conducted: one with motorists, stratified by geographic area (n=2,002); and a truck driver survey (n=448).
Key study results: Highway users noted the lack of nighttime visibility in work zones and problems seeing signs, lane markings, barriers, and construction personnel at night. Truck drivers also described problematic night work zone lighting, (light plants, rotor beams, headlights, etc.). Drivers voiced willingness to accept 12- to 15-minute construction related delays. Highway users in more populated regions experienced longer actual delays than those in rural areas and reported lower tolerance of acceptable delay. All groups cited the need for greater speed enforcement as an essential change for work zones. Drivers most often used signs, television, radio, and newspapers as sources of work zone information. The authors recommend further review of the prevailing problems and identified trends in order to develop corrective action or mitigation strategies.
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Field Evaluation of a Portable Gyratory Compactor
Application of quality management concepts to asphalt paving evolved because recipe specifications frequently proved inadequate for ensuring pavement performance. Quality management of asphalt concrete is founded on the premise that the producer controls the end-quality of the product, including the in-place void content on which pavement performance is highly dependent. In its quality management program the Oregon Department of Transportation (ODOT) originally used the Marshall hammer, since neither the Hveem (kneading) nor Superpave prototype compactor was suitable for field quality control/assurance (QC/QA). Post-SHRP research led to the development of truly portable gyratory compactors, i.e., those of 70 kg to 140 kg mass. Although selecting and proportioning materials as well as compaction are integral parts of the Superpave technology, there is some apprehension given the fact that no strength test is required at low traffic levels.
Given ODOT’s long and successful use of the Hveem method of mix design, the primary objective of this research was to assess the effectiveness of a portable gyratory compactor for field quality control purposes. A secondary objective was to determine the quality of Superpave mixes as measured by Hveem stability. To achieve these objectives plant-produced material was sampled during construction and compacted with both portable and prototype gyratory compactors. Shortly after construction, cores were extracted. All samples (gyratory compacted and field cores) were subsequently tested in the Hveem stabilometer.
The following conclusions are noteworthy: Overall, the operational characteristics of the portable gyratory, including calibration and maintenance, were satisfactory. There was essentially no difference between the portable and prototype gyratory compactors as measured by air void content of 150 mm samples. In no case was the difference in air void content greater than 0.5 percent. Comparison of 100 mm and 150 mm samples compacted in the prototype gyratory was instructive in that the latter were consistently lower in air void content, typically by 0.5 to 1.5 percent. The air void content of plant mix samples compacted to Ndesign gyrations was consistently lower than that of the field cores, generally by at least 2 percent. The range in air void content of plant mix samples compacted to Ndesign gyrations was 3.0 to 8.8 percent, whereas the range in air void content of the field cores was 6.8 to 9.1 percent. The data indicate that there is virtually no difference in air void content between 100 mm and 150 mm field cores. Field cores generally had lower stabilities than did gyratory- or kneading-compacted samples. However, there was virtually no difference in the stability of lab compacted samples, regardless of gyratory type or specimen diameter. None of the field cores, regardless of project, met ODOT’s minimum Hveem stability criterion of 35.
The data gathered in this research indicate that there is virtually no difference between the prototype (Pine) and portable (Test Quip) gyratory compactors as measured by air void content and Hveem stability. Accordingly, it is recommended that ODOT consider the use of the portable gyratory for QC/QA purposes, assuming that the more fundamental issues of Superpave mix design are resolved. Since Hveem stability of field cores did not meet ODOT’s minimum criterion of 35, early and continuous monitoring of the field performance is imperative. As part of the performance monitoring, it is recommended that wheel-path air void content be periodically measured to confirm/refute the Ndesign concept.
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Injected Polyurethane Slab Jacking
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Conventional methods for raising in-place concrete slabs to align roadway sections or to counteract subsidence requires pressure-injecting grout under the slab. As other transportation organizations have had success with the URETEK Method, which utilizes injected polyurethane, Oregon DOT elected to use this method to raise and stabilize a bridge end panel and adjacent concrete slab. A two-year research project was conducted to monitor the stability of the injected slabs and to evaluate the material. The slabs settled by up to 10.5 mm (0.413 in) after two years. The compressive strength of the polyurethane material was not reduced after underground exposure. The ability of the injected polyurethane to penetrate through holes was characterized. An attempt was made to measure the water permeability of the material.
Research Management Peer Exchange 2001
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The Oregon Department of Transportation hosted a research management peer exchange August 20-24, 2001. The purpose of a peer exchange is to give research managers from state departments of transportation and the federal government a means to improve the quality and effectiveness of their research processes, both for the host department and the visiting research managers.
Strain Monitoring for Horsetail Falls and Sylvan Bridges
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Fiber optic sensors were installed on two reinforced concrete bridges that had been strengthened with fiber reinforced polymer composites. The primary objective for one of the bridges was to provide strain data to verify a computer model for the bridge developed under a separate project. A second objective was to evaluate the effect of fiber reinforced polymer composite reinforcement on bridge response. Unfortunately, usable strain data were not acquired prior to retrofit for either bridge to meet the second objective. This report summarizes the procedures used to install and monitor the sensors and the strain results after the composite retrofit.
A Fitness-For-Purpose Evaluation of Electro-Slag Flange Butt Welds
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A fitness-for-purpose evaluation was performed on the electroslag flange butt welds of the I-205, George Abernethy Bridge as per the request of FHWA notices N5040.23 and 5040.29 dated 2/16/77 and 2/23/77 respectively as well as Memorandum HNG-30 dated 6/21/78. This evaluation required gathering knowledge of the material properties, fabrication defects, and service loads pertaining to the weldments in question. With these data the serviceability of the weldments was assessed and retrofit or monitoring requirements were developed that would assure public safety at reasonable operational costs. After 23 years of ongoing testing and study the plan to monitor the welds in question was developed and justified saving the taxpayers over 6 million dollars in retrofitting construction expenses.
Evaluation of Microwave Traffic Detector at Chemawa Rd/I-5 Interchange
In 2001, the Oregon Department of Transportation installed a microwave traffic detection sensor, and compared it’s performance to conventional inductive traffic loops. The objective of the study was to evaluate the capabilities of the microwave traffic detection sensor to function as a viable detection device in a signalized intersection. The sensor was to detect vehicles in advance of the intersection, providing "extension" and "call" functions for the signal controller.
The microwave detector provides a non-intrusive method of detection and the need to cut grooves is eliminated. The microwave can be installed and maintained from the shoulder area with lower impact on the motorist. Safety for highway workers is also improved.
The Remote Traffic Microwave Sensor was installed and traffic counts made over four weeks. The microwave sensor generally counted lower than the traffic loops. Potential errors for various traffic conditions for both the inductive loops and the microwave sensor were identified and analyzed. Although the counts differ, the microwave provide reasonable detection for the extension and call functions.
This study did not look at long term performance or cost benefits of the detector.
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Performance of Zinc Anodes for Cathodic Protection of Reinforced Concrete Bridges
Operation of thermal spray zinc (Zn) anodes for cathodic protection (CP) of reinforced concrete structures was investigated in laboratory and field studies conducted by the Albany Research Center (ARC) in collaboration with the Oregon Department of Transportation. The purposes of the research presented in this report were: evaluate the need for preheating concrete to improve the adhesion of the anode; estimate the service life of thermal spray Zn CP anodes; determine the optimum thickness for Zn CP anodes; characterize the anode-concrete interfacial chemistry; and correlate field and laboratory results.
Laboratory studies involved accelerated electrochemical aging of thermal sprayed Zn anodes on concrete slabs, some of which were periodically wetted while others were unwetted. Concrete used in the slabs contained either 1.2 or 3 kg NaCl /m3 (2 or 5 lbs. NaCl /yd3) as part of the concrete mix design. The Zn anodes were applied to the slabs using the twin wire arc-spray technique. Half of the slabs were preheated to 120-160oC (250-320oF) to improve the initial Zn anode bond strength and the other half were not. Accelerated aging was done at a current density of 0.032 A/m2 (3 mA/ft2), 15 times that used on Oregon DOT Coastal bridges, i.e., . 0.0022 A/m2 (0.2 mA/ft2)
Cores from the Cape Creek Bridge (OR), the Richmond San Rafael Bridge (CA), and the East Camino Underpass (CA) were used to study the anode-concrete interfacial chemistry, to relate the chemistry to electrochemical age at the time of sampling, and to compare the chemistry of the field anodes to the chemistry of anodes from the laboratory studies. Cores from a CALTRANS study of a silane sealant used prior to the application of the Zn anodes and cores with galvanized rebar from the Longbird Bridge (Bermuda) were also studied.
Aged laboratory and field anodes were characterized by measuring some or all of the following parameters: thickness, bond strength, anode-concrete interfacial chemistry, bulk chemistry, anode resistance, circuit resistance, electrochemical age, and air and water permeability.
Models are presented for the operation of periodically-wetted and unwetted thermal spray Zn anodes from the initial energizing of the anode to the end of its service life. The models were developed in terms of bond strength, circuit resistance, anode-concrete interfacial chemistry, electrochemical age, and anode condition.
The most significant results of the research are: (1) preheating concrete surfaces prior to coating with Zn is unnecessary; (2) anodes generally fail due to loss of bond strength rather than Zn consumption; (3) Unwetted anodes fail more quickly than periodically-wetted anodes; (4) 0.47-0.60 mm (12-15 mil) anode thickness is adequate for most Oregon DOT coastal impressed current CP (ICCP) installations; (5) based on bond strength, thermal spray Zn ICCP anode service life is approximately 27 years at 0.0022 A/m2 (0.2 mA/ft2); (6) anode reaction products alter the anode-concrete interface by rejecting Ca from the cement paste, by replacing it with Zn, and by the accumulation of a Zn mineral layer that includes chloride and sulfur compounds; (7) CP system circuit resistance provides an effective means for monitoring the condition of Zn ICCP anodes as they age.
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Development of Maintenance Practices for Oregon F-Mix
Oregon Department of Transportation (ODOT) has been using open-graded F-mix since the 1970’s. These porous asphalt concrete mixes have become the pavement-of-choice for rural high-traffic sites statewide, as they promote drainage and reduce hydroplaning, spray and splash. Deformation rutting has also been reduced.
Standard pavement maintenance procedures have been developed for dense-graded mixes, but use of these methods on F-mix diminishes its free-draining attributes and changes noise and ride characteristics. This project was developed to study maintenance practices for F-mix and recommend standardized procedures for Oregon. Unfortunately, no new techniques specific to porous pavements or open-graded friction courses could be identified, so researchers surveyed ODOT maintenance personnel to collect experience and recommendations for best practices for F-mix maintenance. Field monitoring was done on specific maintenance projects over several years.
This report documents the results of the surveys and field evaluation work, and presents recommendations for improving preventative maintenance, corrective surface maintenance, and winter maintenance practices. Also recommendations are provided for documenting maintenance practices using the pavement management system and maintenance management system.
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Weight Enforcement and Evasion: Oregon Case Study
This study examines the incidence of overweight trucks and its relation to regulatory enforcement activity. Addressed are questions of scale operations in relation to weight violations and the effectiveness of enforcement levels, automated preclearance systems and weigh-in-motion (WIM) technology. The study also compares state-by-state enforcement intensity and penalty levels to understand their relative effective deterrence.
To answer these question the Oregon Department of Transportation (ODOT) identified an I-5 freight corridor and two potential bypass routes to collect data from three WIM sites. Data collection occurred before, during and after an extended closure of the I-5 weigh station. The traffic volume data did not indicate evasion behavior on the bypass routes, nor diversion to I-5 during closure. Only the I-5 site exhibited a statistically significant pattern of increase in mean GVW from baseline through closure (.4%), and a decrease of 1.2% following reopening. The incidence of overweight vehicles on I-5 also exhibited a statistically significant increase from 2.27% before closure to 3.67% during closure and a decline to 3.19% after re-opening. Additional analysis explored the incidence of overloading among ODOT Green Light preclearance program participants. Green Light program participants were less responsive to scale closure than non-participant vehicles.
The study results suggest the following: 1) Relatively aggressive enforcement in Oregon (more weighings and stiffer fines for overweight violations) creates a climate where a single-site temporary suspension of weighing activity has less impact on trucking operations; 2) Weight enforcement activity at one site on I-5, the major West Coast freight corridor, may have little impact on interstate and international shipments; and 3) Green Light program participants may be either self-selecting compliant operators or, unwilling to jeopardize the benefits of the program by engaging in overloading.
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Survey Methods for Assessing Freight Industry Opinions
Freight transportation concerns and issues have received increasing attention during the 1990s. Public sector agencies use various methods to identify locations where improvements are needed to facilitate freight movements. Concerns and needs regarding improvements have been based on a blend of modeling, technical data and estimates, reviews of plans and other documents, personal observations, and public input. Various observers believe information from these sources should be combined with more specific information from shippers and motor carriers moving freight. There has been little definitive research done, however, on how best to survey the freight community.
In order to establish the most effective means of gathering perceptions of infrastructure problems encountered by the freight industry on the state highway system and supporting road network, the Oregon Department of Transportation (ODOT) sponsored research on a methodology for conducting surveys of shippers and motor carriers. A series of pilot studies resulted in the development of a telephone survey methodology capable of yielding a 60% response rate. To demonstrate this methodology a full-scale survey was also conducted with a statewide sample of nearly 3,600 firms. This surveying effort achieved a 61% response rate and yielded over 2,200 problem descriptions, locations and information on the impacts of the problems on freight operators. Analysis of the data showed minimum levels of non-response bias and a fairly balanced response rate from all regions of the state. The research report also discusses possible approaches for further analysis of the survey data and potential uses for freight transportation planning purposes.
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Crumb Rubber Modified Asphalt in Oregon
Since 1993, the Oregon Department of Transportation (ODOT) has been monitoring performance of seventeen rubber modified asphalt and asphalt concrete sections constructed on Oregon highways. The study originated in response to the Intermodal Surface Transportation Efficiency Act (ISTEA, 1991) which mandated the use of tire rubber in pavements. The ISTEA requirement was eventually repealed, however, the study continued to document pavement performance in an effort to determine if rubber modified asphalt concrete pavements are feasible in terms of construction and life cycle cost.
The rubber modified sections that performed the worst included those constructed using the dry process (rubber modified asphalt concrete—RUMAC). The sections performing the best included open graded mixes constructed using the binder PBA-6GR (a rubber modified asphalt). After five years, the PBA-6GR pavements were performing as well or better than the control sections. The cost of the mixes constructed in 1993 and 1994 with PBA-6GR was about 12% more than the control sections. Over the life of the pavement, the terminal blend asphalt rubber (PBA-6GR) may be cost effective.
This report documents the performance of the rubber modified and control sections including distress information, skid and ride data and laboratory testing results. In addition, non-ODOT projects were reviewed and discussed.
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