Oregon's Mobility Needs: Social Service Provider Survey
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In 1998, the Oregon Department of Transportation undertook the Social Services Provider Survey as part of an investigation of the transportation needs of mobility impaired individuals in Oregon. This survey was designed to gain information about the transportation needs of the low income, elderly and disabled from the perspective of organizations who work closely with mobility impaired populations. It followed statewide surveys of transportation needs from the perspectives of the mobility impaired individuals and public transportation providers. Local offices providing state- or federally-supported social services were mailed a written survey. Over 400 agencies responded representing education, senior & disabled services, health, vocational rehabilitation, community colleges, mental health and others.
The study found that nearly all agencies serve the mobility impaired, with approximately 40% of their clients having one or more mobility impairments. The findings showed that 75% of the agencies provide some type of transportation for their participants. Only 4% of the agencies charge for transportation. Funding comes from a wide variety of sources, some requiring specific limits on types of trips or groups of participants. Policy limits increase the travel limitations of these programs.
Agencies rated public transportation’s ability to provide trips. Nine of ten felt that their clients had additional transportation needs not currently met by public transportation. Over half estimated that an average of two or more additional trips per week was needed, with 18% noting the need for more than six additional trips. Social/recreational, work, personal business and shopping trips were the most difficult to obtain. More services, more hours and days of operation, and better connections with other services were key recommended improvements.
Findings were consistent across the three surveys. Transportation needs for social service clients are similar to the needs of seniors and persons with disabilities. Statewide, there is a need for more transportation services. Service improvements are needed, though specific improvements vary geographically.
Compaction and Measurement of Field Density for Oregon Open-Grades (F-Mix) Asphalt Pavements
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A research project conducted by Oregon State University (OSU) and the Oregon Department of Transportation (ODOT) investigated compaction of Oregon F-mix asphalt pavement, an open-graded mix with 25-mm maximum size aggregate and air voids typically in the 17-26% range. The research sought to determine
- variations in compaction resulting from different compaction patterns, and
- accuracy of measurement of field densities to determine the feasibility of a density specification
Nine different compaction patterns varying from 2 to 6 passes with minimum 7 Mg rollers and utilizing combinations of static and vibratory compaction were employed on six different overlay paving projects. Core densities were determined at five random locations on each control strip, resulting in 270 (5x6x9) core densities. Densities between compaction patterns were compared. Although the data indicate that introducing vibration and increasing the required number of passes from 4 to 6 would increase densities from those achieved with the current specification, the increase is relatively small and the effect on open-graded pavement performance is unknown.
Prior to coring, field densities were determined by nuclear density measurement and through measurements with the Pavement Quality Indicator (PQI), a measuring device being developed by Trans Tech Systems Inc. and the FHWA. Data obtained in this study did not show good correlations between measurements with either device and core densities.
Epoxy Coated Reinforcement Study
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This report evaluates the use of Scotchlite 213 epoxy coated reinforcement in Oregon coastal environments. There is an extensive body of knowledge documenting epoxy coated reinforcement research in North America in the last 20 years. The research has produced mix results. However, recent studies conducted by Clear and others for the National Cooperative Highway Research Program, by Kessler and others for the Florida Department of Transportation and by Weyers and others in Virginia, provide evidence of poor performance of epoxy coated reinforcement in coastal bridge structures.
In 1989, the Oregon Department of Transportation removed a concrete test beam reinforced with Scotchlite 213 epoxy coated reinforcement after nine years of service from Yaquina Bay in Newport, Oregon. Results of the testing and evaluation showed that there was adhesion loss of the coating attributed to low blast profile of the steel and low coating thickness. There was observed corrosion along the longitudinal bars and hoop reinforcement that were located within the tidal zone.
Another concrete beam reinforced with Scotchlite 213 epoxy coated reinforcement was removed from Yaquina Bay in 1998 after eighteen years of exposure. The testing and evaluation showed that:
- Half-cell potential measurements within the beam’s tidal zone exceeded the 90% probability threshold (-0.35 V) for corrosion to occur.
- The chloride concentrations were significantly elevated within the beam’s tidal zone.
- The adhesion loss was greatest within the tidal zone and in some areas, there was total loss of adhesion.
- Most of the observed corrosion of the Scotchlite 213 epoxy coated reinforcement was within the tidal zone.
Based on the literature documenting previous studies and ODOT’s testing and evaluation conducted in 1989 and in 1998, the use Scotchlite 213 epoxy coated reinforcement for long term protection against corrosion in coastal bridges is not recommended.
Guardrail Installation Noise Level Evaluation
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The Oregon Department of Transportation (ODOT) Environmental Services Unit evaluates the impacts of noise and mitigation of noise issues. ODOT currently requires noise level evaluation for proposed construction projects when threatened or endangered wildlife may be adversely affected.
A commonly used piece of equipment on construction projects is the guardrail post driver. The guardrail post driver does not have a baseline noise level established. As a substitute, ODOT biologists have used the baseline noise level associated with the pile driver for noise level assessments. This study establishes a more accurate baseline noise level for the guardrail post driver, which is lower than the baseline noise level of the pile driver. Due to this lower noise level, there is a potential increase in safety and decrease in cost.
Asphalt-Rubber Concrete (ARC) Evaluation
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This report reviews the construction of four pavement test sections using asphalt-rubber as the binder and three hot mix asphalt concrete pavement control sections. The pavements were constructed in Klamath Falls, Oregon in 1992. The control sections were constructed with hot mix asphalt concrete. The test sections consisted of one gap graded asphalt-rubber concrete (ARC) mix and two open graded ARC mixes. The fourth test section was constructed using a powdered rubber asphalt-rubber concrete (PRARC) open graded mix. The ARC binder was made by blending shredded tire material and asphalt. The PRARC binder was made by blending natural rubber and asphalt. Powdered rubber from tire sources was supposed to have been used, but unfortunately, natural rubber was used instead. The blending for both types of binders was done at the asphalt plant by International Surfacing, Inc. There were two open graded mix control sections and one dense graded mix control section.
There were no problems in constructing the open graded and gap graded ARC test sections. There were some concerns with construction of the PRARC mix. Possibly because of the natural rubber or the slightly higher binder content, the PRARC mat was sticky. Just after compaction, several applications of sand were needed as a blotter on the surface of the mat prior to opening the section to traffic.
Urban Freeway Reconstruction Workshop
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This report summarizes the recommendations of participants attending a workshop on March 16-17, 1999 in Portland Oregon, to consider options for preservation or reconstruction of Interstate 5 (1-5) in Portland. Participants from state Departments of Transportation in Georgia, Washington, Michigan and Oregon joined Federal Highway Administration, City of Portland and industry personnel to discuss this stretch of 1-5, which is nearing the end of its 30-year design life.
The participants reviewed the project considerations and constraints, discussed similar project experiences, and brainstormed options for preservation/reconstruction and traffic management. Seven options were compared for five factors:
- pavement related costs
- structure raising costs
- traffic control / detour costs
- other costs
- user costs
Two promising options were analyzed in detail: Full reconstruction with concrete (full closure and partial closure) and Asphalt concrete overlay. A life-cycle cost analysis was done for both options.
The report includes project background, examples of similar projects from Georgia and Michigan, the list of brainstormed options, details of options discussed in more depth, and identified issues relating to contracting options.
Geotextile Fabrics Under an Asphalt Concrete Overlay to Retard Reflective Cracking
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In 1991, the City of Portland selected a section of East Burnside from 39th Avenue to 47th Avenue to grind-out and overlay asphalt concrete over an old Portland cement concrete (PCC) pavement. Geotextiles were used to provide reinforcement and retard reflective joint cracking. A test section on the eastbound lanes of Burnside between 44th Avenue and 45th Avenue was placed in September 1991. The test section included four cracks, which were covered with Glasgrid 8501 or Polyguard NW-75. A control section in the westbound lanes between 44th and 45th Avenue was also constructed about the same time. The final inspection was completed in June 1998. A few small cracks have developed in the control and test sections. Because the control has only slightly more cracking than the test section, the benefit of the geotextiles is questionable at this time. The success of the project appears to be due to an excellent paving job.
Ticket Taker Automation
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The Oregon Department of Transportation requires an ODOT employee to collect weigh slips from delivery vehicles on road construction. These delivery vehicles may be hauling asphalt mix or aggregates. The person, usually a temporary employee, is given the job title "ticket taker". The job is one of the most dangerous jobs on the construction project. The purpose of this project was to eliminate the dangerous ticket taker job with an automatic system.
The ticket taker automation system is a very high frequency radio operating at 2.45 GHz. An interrogator unit attached to a laptop computer, transmits data to a small transponder that can store 256 bytes of data. Transponders were attached to the trucks hauling asphalt mix. At the hot mix plant, a signal is sent to the transponder and stored. At the jobsite, the interrogator reads the signal and stores the data in the attached computer. Both a scale unit and a job site unit are required for this system.
This project was a preliminary test of the system in a road construction environment. The results of the study indicate that the limited range of the system (20 m) would require an operator to move the system as the job progressed forward. Ticket taking would not be eliminated, but made safer by automation. Based on the results of the study, the system is not suitable for implementation at this time.
Geosynthetics for Reflective Crack Control
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Reflective cracking due to shrinkage and brittleness in asphalt pavements can seriously degrade an asphalt overlay before it is near its design life. Geosynthetics have been used to impede the reflection of existing transverse cracking to the new overlay. The geosynthetics are intended to minimize the tension transferred to the overlay from the existing pavement. The Oregon Department of Transportation (ODOT) installed a test section consisting of 120 transverse cracks treated with five different geosynthetic types, 22 transverse cracks treated with crack filling only and a control section of 20 untreated transverse cracks. The test and control sections were constructed over an open-graded asphalt concrete pavement. The overlay was also an open-graded mix. The 140 transverse crack section is located on US Highway 97 between Milepoint 213.58 and Milepoint 217.64.
Albany Case Study: Indirect Land Use and Growth Impacts
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To improve environmental analysis of indirect land use impacts of highway capacity improvements, this study analyzed the land use and growth patterns of 20 Oregon communities over 20 years. Using a Geographic Information System and aerial photos, growth patterns were categorized and mapped. Factors related to land use and transportation were evaluated for their relationships to resulting growth patterns. These relationships were further investigated in four in-depth case studies of development prior to, during, and after construction of a highway capacity improvement. Additional case studies are currently underway. The primary product of this research will be guidance for completing an assessment of the indirect impacts on land use and growth of a highway improvement. This assessment is required by environmental regulations, but tools and data for developing general land use forecasts is limited. The guidebook will include examples from the case studies, data types and possible sources, and guidance on using GIS tools for comparing alternative scenarios. Interim reports are available via the Research Internet web site. Additional case studies and a final report are scheduled to be published in the fall of 2000.
Field Application of a Thermal-Sprayed Titanium Anode for Cathodic Protection of Reinforcing Steel
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This study provided the first field trial of a catalyzed, thermal-sprayed titanium anode for cathodic protection of steel reinforced concrete structures. Catalyzed titanium as an anode material offers the advantage of long life due to the inherent non-corrosive nature of the metal in atmospheric exposure. To continue to serve as an anode, the titanium will require a periodic and easily accomplished re-application of the catalyst rather than re-application of the metal. The purpose of this study was to evaluate the installation and operation of the catalyzed titanium anode and to evaluate the economics of the titanium anode system compared to thermal-sprayed zinc.
The initial phase of the study included modification of the spray equipment for spraying titanium wire and determination of the optimal spray parameters for applying the titanium anode to the bridge. Coating resistivity was found to be the best measure for evaluating the effectiveness of the coating. Decreasing spray distance, increasing current, and using nitrogen as the atomizing gas (propellant) all decrease coating resistivity. A multiple regression equation developed from the collected data showed that, for the data collected in this study, spray gun travel speed and atomizing gas pressure have an insignificant effect on coating resistivity
Coating analysis showed that the arc-sprayed titanium is a non-homogeneous coating due to reactions with atmospheric gases. The coating contains, on average, 88 weight percent titanium. The principal coating constituents are a -Ti containing interstitial nitrogen and interstitial oxygen, and g -TiO with the possibility of some TiN. The coating consists of alternating layers of a -Ti rich and g -TiO rich material. The use of nitrogen as the atomizing gas results in a coating with less cracking, more uniform chemistry, and therefore, lower coating resistivity than is produced using air atomization.
The field trial resulted in installation of 280 m2 (3015 ft2) of catalyzed, arc-sprayed titanium on the Depoe Bay Bridge. Several lessons were learned during the field trial. Although use of a grade 1, annealed titanium wire for spraying was found to reduce equipment wear, frequent equipment maintenance caused by rapid wear of the copper spray tips had a significant impact on operator productivity. The switchmode power supply furnished with the spray equipment was unable to provide the stable arc needed for smooth operation of the spray equipment. Current distribution plates embedded flush in a concrete patch material proved to be the best method for providing a low resistance connection between the anode and the power supply.
Although some difficulty was experienced during the field trial, the costs for performing this work exceeded the bid costs for installing arc-sprayed zinc on this same structure by just 18 percent. If the long-term performance of the catalyzed titanium anode system is proven, the arc-sprayed titanium system will provide a life cycle cost advantage over the arc-sprayed zinc system.
Superpave Binder Implementation
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Oregon Department of Transportation (ODOT) has specified performance-based asphalts (PBAs) since 1991. Developed by the Pacific Coast Conference on Asphalt Specifications (PCCAS) in 1990, the PBA concept uses conventional test methods for classification and facilities binder selection based on climatic conditions. The Conference plan was to use the PBA concept and conventional tests as an interim approach which would eventually be replaced with the Strategic Highway Research Program performance grade (SHRP PG) specification and supporting tests. As a first step in the SHRP implementation/validation effort ODOT has evaluated its commonly used PBA grades in terms of the SHRP (now called Superpave) protocols. The limited binder evaluation to date suggests the following equivalencies: PBA-2s may be classified as PG 64-16 or PG 64-28; PBA-3s as PG 58-34 or PG 64-28; PBA-5s as PG 64-22; and PBA-6s as PG 58-28 or PG 64-34. There was not always agreement with regard to PG classification between the research results and the supplier data, nor was there always agreement among the suppliers. As described by the number of different performance grades for a particular PBA, PBA-2 appeared to be the least consistent whereas PBA-5 and PBA-6 appeared to be the most consistent. Comparison of Superpave PG and conventional binder test data indicates that there was no relationship between the high temperature performance grade and kinematic viscosity. However, there was a moderate relationship between the high temperature performance grade and absolute viscosity as values of explained variation (R2) of the unaged and RTFO-aged binders were 0.38 and 0.52, respectively. The relationship between the low temperature performance grade and penetration at 4°C and 25°C were significantly higher with values of explained variation for the RTFO-aged binders of 0.80 and 0.84, respectively. The diversity of Oregon’s climate suggests that as many as 13 to 14 binder grades might be "needed" at the 98 percent level of reliability, although many grades overlap. Realistic constraints and practical considerations such as readily available binder sources and state-maintained-road-miles associated with a particular performance grade led to the recommendation that four PG binders be specified: PG 58-22 and PG 64-22 west of the Cascades; PG 58-28 and PG 64-28 in the central part of the state; and PG 64-28 in the eastern part of the state. Preliminary economic analysis suggests that implementation of the PG system could provide substantial savings. Because of Oregon’s extensive use of open-graded friction courses, additional work must be done to determine what effects, if any, the PG classification might have on this mix type in terms of field performance.
Oregon's Mobility Needs: General Population Survey and Transportation Provider Survey
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In 1998 the Oregon Department of Transportation conducted a statewide survey to assess the size and geographic distribution of Oregonians who are "mobility impaired," i.e. dependent on others for meeting their transportation needs. The study collected data on the functional abilities and travel habits of the mobility impaired and assessed the effectiveness of current transportation services in meeting their needs. A survey of publicly funded transportation service providers collected information on current services, service improvements and perceptions of latent demand.
The major findings and conclusions of the research were as follows: Mobility impairment is a significant problem in the state of Oregon. Improvements to transportation systems should be targeted across the state and in areas of varying population density. The mobility impaired have a wide variety of needs that require complex solutions. Regular fixed route service can help meet the needs of mobility impaired individuals. There are opportunities to meet the needs of mobility impaired individuals by offering regularly scheduled public transportation to key locations in the community. Latent demand for transportation is significant, both for trips within communities as well as for trips between communities. There is significant need for additional fixed route trips and/or Dial-A-Ride trips, both in communities that currently have these services, as well as in communities that do not. The mobility impaired population with access to service report three areas where their needs are not being met: ease of access of service, employees knowledgeable about people with special needs and printed schedules that are easy to understand. Further study is recommended to better understand the needs of social service agency clients, the needs of other transportation disadvantaged individuals, and the costs of meeting the needs of mobility impaired persons.
Evaluation of Supplemental Shields at Railroad Crossings
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The Oregon Department of Transportation evaluated the use of a supplemental shield for use at passive railroad crossings. These shields used reflective sheeting materials in a modified chevron pattern, attached below the railroad crossing sign. Differing color combinations and types of reflective sheeting were reviewed.
The study evaluated whether the devices could decrease vehicle-train accidents at highway-rail crossings, and to determine an appropriate traffic control device that could be effective at reducing accidents and be acceptable for inclusion in ODOT's Sign Policy and Guidelines. The research also evaluated the use of reflective tape and measured the reflectivity of the tape and shields. The report contains review team findings and recommendations for sign improvements and use of the shields.
The Oregon DOT Slow-Speed Weigh-in-Motion (SWIM) Practices
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Weigh-in-motion (WIM) systems have been increasingly used to screen potentially overweight vehicles. However, under slow speed conditions (less than 10 mph), WIM scales appear to be capable of estimating static gross vehicle weight to within ± 10% with 95% confidence. This report presents findings from a year-long field test of a slow-speed weigh-in-motion (SWIM) system. A regression model was used to improve accuracy and precision by accounting for the effects of time, weather, and vehicle speed. Following correction, accuracy improved to ½ of 1% at both the axle and vehicle levels. Also following correction, 95% of the observations were within 6.8% of the static scale weight at the axle level. At the vehicle level, precision improved to within 4.4%. The precision of the corrected data for vehicles and tandem axles approaches the levels stated by the ASTM in its standard specification for Type IV (enforcement applications) WIM systems.
Base Isolation Bearing (Dynamic Isolation Systems, Inc.)
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A 1,000-foot long, continuous, post-tensioned box girder bridge was constructed with proprietary seismic isolation bearings to address stringent design loading requirements while accommodating shrinkage deformations as well as elastic and creep deformations from post-tensioning. The bearing devices, supplied by Dynamic Isolation Systems, Inc., are rubber based with lead cores and introduce lateral flexibility and damping between the superstructure and the substructure. These properties modify and reduce the structure's response to seismic loads. After four years of service the bearings are performing well. Only three minor deficiencies have been observed: rust on the bearing plates, bulging of some bearings, and bearing inclined from vertical.
Port of Entry Advanced Sorting System (PASS) Operational Test
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In 1992 the Oregon Department of Transportation undertook an operational test of the Port-of-Entry Advanced Sorting System (PASS), which uses a two-way communication automatic vehicle identification system, integrated with weigh-in-motion, automatic vehicle classification, and over-height detection tied into a heavy vehicle database. The purpose of this operational test was to demonstrate the feasibility of using this system to let trucks directly bypass the port and the static scale weighing process, thus resulting in significant benefits for both the carriers and the State. An additional purpose was to test the use of "double-threshold" bending plate type weigh-in-motion scales to improve the weighing accuracy as compared to single weigh-in-motion scales. In this Final Report, the authors describe the PASS system and present results obtained from three years of operation. Results from a survey of trucking firms are presented. Results from the testing of the double-threshold weigh-in-motion scales are also presented and discussed.
Some problems with the state-of-the-art PASS occurred, causing interruptions. Most were software problems, which were resolved. The survey indicated that truckers and trucking firms using the two-way transponders were pleased with the system. The project proved that the mainline sorting of heavy vehicles to bypass or enter a Port-of-Entry is workable with current technology.
The variability of weight measurements using the double-threshold weigh-in-motion scales was found to be less than the variability of measurements from the twin weigh-in-motion scales when taken separately. Unfortunately, the weights provided by the WIM scales appeared to be biased toward the mean in spite of careful calibration. Thus the value of double-threshold WIM scales remains unclear.
Desert Varnish - Rocky Point Viaduct
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In 1995, ODOT sprayed the reinforced shotcrete slope stablilization project near Port Orford on US 101 with Permeon, a rock coloring material also called desert varnish. The application colored the shotcrete to a weathered-looking dull brown, masking its gray-white concrete appearance. Some weathering in the last three years has changed the color. Water and mud running from the above cliff have added white and brown streaks. Also, wind and salt air erosion have faded some of the coloring. The test area is still darker than the control section which received no application.
The value of the desert varnish appears to be marginal. If the three-year trend continues, the salt air and strong winds will discolor the entire treatment.