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ODOT Research Unit - Active Projects
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Article Content
Mechanistic Pavement Design Input Parameters Project Coordinator:
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Norris Shippen
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Research Agency:
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Oregon State University
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Principal Investigator:
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Todd V. Scholz
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Start Date for ODOT:
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October, 2005
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End Date for ODOT:
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February 28, 2008
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BACKGROUND: Current splling erroers national pavement design procedures are outdated and typically conservative for the traffic volumes on most of the NHS highways in Oregon. The current 1993 AASHTO Pavement Design Procedure is empirically based and was developed in the 1960’s. AASHTO is in the process of developing a new design procedure that is mechanistic-empirical based. The new design procedure will require ODOT to develop new inputs and calibrate the procedure to local conditions and materials. An ODOT research project is currently underway for the input parameters for AC strength, dynamic modulus. Other inputs required in the new design procedure include aggregate base and subgrade soil properties, calibration of failure criteria and functions to local conditions, AC mix volumetric properties and climatic data OBJECTIVE: The objective of this research project is to develop the appropriate inputs for use in mechanistic and perpetual pavement design procedures. PROPOSED ACTIVITIES: Determine what information is currently available on mechanistic pavement design. Test and recommend appropriate back calculation software. Determine what information ODOT currently has that can be used in developing material property inputs for mechanistic and perpetual pavement design procedures. Make a recommendation on the use of available climatic data resources. This research will also determine what additional material properties or inputs are required for implementation of the AASHTO mechanistic design procedure or other perpetual pavement design procedures and recommend future research. MECHANISTIC PAVEMENT DESIGN INPUT PARAMETERS WORK PLAN Quarterly Reports:
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Institutional Barriers Delaying Incident Clearance | Project Coordinator |
June Ross |
| Research Agency: |
Oregon State University |
| Principal Investigator: |
Karen Dixon |
| Start Date for ODOT: |
October, 2007 |
| Completion Date for ODOT: |
July, 2008 |
BACKGROUND: The Oregon Department of Transportation (ODOT) has a comprehensive incident management program in place. Due to cooperative efforts among ODOT, Oregon State Police, local police, and emergency providers most incidents are cleared rapidly and traffic operations resume normally. However, a major traffic-related incident can take considerable time to clear; closure of a major highway during peak travel periods can cause major problems. It is not known to what extent institutional constraints may account for some inefficiency in incident clearance. These inefficiencies may result in extended time elapsing from incident detection through final site clearance. OBJECTIVES: The research proposed in this study will address several key objectives. These are summarized as follows: · Using a variety of data resources, examine recent traffic incidents where full highway closure occurred to determine the extent to which the incident and associated traffic obstructions impact traffic operations; · Identify institutional barriers that may affect the rapid clearance of incidents occurring on Oregon highways; and · Identify administrative procedures that could be implemented to expedite incident clearance and estimate the benefit of these recommended procedures. 3.1 Benefits Benefits of improved incident management are far-reaching. In addition to the potential for reducing the non-recurrent delay that often follows an incident, other benefits include reduced fuel consumption and vehicle emissions, fewer secondary crashes that result directly from the congested environment, improved travel reliability, and less direct impact on the stress or aggression levels of drivers. For the region, quick clearance times would benefit freight delivery, and minimize the impact on adjacent land use and the economy. An additional benefit of this project would be improved understanding by participating organizations regarding incident response and clearance procedures by various responding agencies. IMPLEMENTATION: Through the diverse structure of the TAC membership, the research results will be distributed to the various responding agencies in a truncated summary format suitable for use by multiple agencies. The results of this research may potentially modify the way that responding agencies in Oregon react to an incident, change the procedure for incident clearance, and result in a safer incident site for responders, injured parties, and the general traveling public. It is also possible that additional equipment investments may be identified such as adding supplemental message signs, providing additional incident response trucks, and improving information delivery to the traveling public and freight carriers. The research results will be incorporated, as appropriate, in the Oregon Traffic Incident Management Strategic Plan currently being developed under the leadership of ODOT’s Maintenance Leadership Team. INSTITUTIONAL BARRIERS DELAYING INCIDENT CLEARANCE WORK PLAN Quarterly Reports:
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Strengthening Methods for Deficient Flexural Steel Anchorages in Bridge Girders | Project Coordinator |
Steve Soltesz |
| Research Agency: |
Oregon State University |
| Principal Investigator: |
Christopher Higgins |
| Start Date for ODOT: |
July 2012 |
| Completion Date for ODOT: |
December 2014 |
BACKGROUND: Many of Oregon’s reinforced concrete deck girder (RCDG) bridges built in the 1950’s were designed to permit higher shear stress in the concrete than is permitted by current AASHTO standards. In addition, modern truck loads are significantly larger than service loads of the past. A large number of reinforced concrete bridges in the ODOT inventory have exhibited significant diagonal shear cracks. Many of these bridges remain in service. Rating these bridges requires checking flexural steel anchorage capacity per AASHTO LRFD 5.8.3.5. Research has shown that the check is needed to ensure that shear-tension failures do not occur in bridge girders. Application of LRFD 5.8.3.5 to several bridges shows that this is a commonly encountered limitation in rating and rehabilitation. Because flexural steel anchorages in RCDG bridges have limited reserve capacity and no proven flexural strengthening methods have been validated, otherwise serviceable bridges cannot be effectively rehabilitated and may need to be replaced or posted.
Many RCDG bridges need to be strengthened in order to maintain performance and safety. Carbon fiber reinforced polymer (CFRP) strips adhered to the concrete surface is the most expedient method for flexural strengthening, but strengthening for flexure near a crack is problematic because the crack tends to cause the strips to peel away when loaded. Recent tests at Oregon State University show excellent promise for near-surface mounted carbon fiber reinforced polymer (NSM-CFRP) as an effective strengthening system even near cracks. This relatively new technology involves cutting a groove in the surface concrete, placing CFRP material (often a carbon fiber tape or precured laminate) in the groove, and applying an epoxy adhesive to bond the CFRP to the concrete. The installation requires substantially less labor and uses significantly less adhesive materials than alternative CFRP methods. However this technique has not been proven specifically for strengthening the steel reinforcement anchorages; therefore, design methods are lacking. In addition, because the retrofitted strengthening elements will be oriented across existing shear stirrups, the cut groove with fiber strip approach used for shear strengthening may need to be modified to avoid cutting the stirrups. Finally, the application of metal alloys may be beneficial to allow hooked anchorage of the material into the core region and application of surface textures to enable greater bond strength between the adhesive and NSM materials.
OBJECTIVES: The objective of the research is to provide proven options for strengthening the flexural anchorage on cracked reinforced concrete girders.
Benefits
Research will ensure that the capacity of existing deck girders with deficient flexural anchorages is adequately characterized. Strengthening approaches will be experimentally validated to effectively extend the service life of these bridge members, that the repaired member performance can be reasonably predicted, and that ODOT engineers can make effective and economical selection of strengthening/replacement alternatives. These will help ensure continued safe operation of the bridges while minimizing unnecessary replacement, posting, or strengthening and facilitate economic movement of freight. Without this research, deficient anchorages cannot be effectively strengthened and bridges that are otherwise satisfactory may need to be replaced or posted.
IMPLEMENTATION: Meetings and workshops will be held with ODOT Bridge section personnel to present research findings in-progress as well as summary findings. Background information and findings will be described in reports, papers, and peer-reviewed journals. Design examples will be provided for the methods developed. Web-based access to in-progress test data and images, analytical methods, and summary findings will be available on-line where appropriate.
WORK PLAN METHODS FOR STRENGTHENING FLEXURAL STEEL DETAILS IN REINFORCED CONCRETE BRIDGE GIRDERS WORKPLAN Quarterly Reports:
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Implementing Safe and Effective Speed Reductions for Specific Freeway Work Zones | Project Coordinator |
Jon Lazarus |
| Research Agency: |
Oregon State University |
| Principal Investigator: |
John Gambatese |
| Start Date for ODOT: |
March 30, 2012 |
| Completion Date for ODOT: |
January 31, 2013 |
BACKGROUND: Roadway interstate pavement preservation projects (e.g. pavement overlays, “chip seal” operations, etc.) typically require construction workers to conduct their work in close proximity to ongoing traffic. Pavement preservation projects commonly reduce traffic flow to a single lane while work is undertaken in an adjacent lane. During the lane closures, the paving operations place workers on the roadway within a protected work zone. In some places they only have a line of cones and a few feet, separating them from passing traffic. This situation creates significant safety risk for both the workers and passing motorists. Inattentive or speeding drivers, careless workers, misplaced cones, and hazardous roadway conditions can lead to crashes and ultimately work zone injuries and fatalities. The severity of a crash intensifies as the speed of traffic increases. As a result, preservation projects on high-speed roadways present an increased risk of serious and/or fatal injuries to workers, motorists and their passengers.
Vehicle speed is inextricably connected to the performance of work zone designs and there is a widely held perception that speed is one of the most significant factors in road crashes (Mahoney et al. 2007). However, safely controlling and reducing vehicle speeds through work zones to reduce the risk can be difficult on high-speed roadways. On such roadways, it has been suggested that reducing traffic speeds to 35 mph would enhance the safety of the workers and traveling public; however, this differential in speed on an interstate only has a few cases studies as examples (one recently in Oregon). Additional safety measures in planning, signage, and notification to the driving public would be needed to reduce the significant risks to motorists as they navigate through the active work zone and react to the large differences in speed. Large speed reductions during nighttime work – a time when preservation projects are often conducted – can complicate the situation more, be difficult to implement, and may increase risks. Current speed reduction and traffic calming methods under these conditions may be adequate, however since there are only a few case studies it is difficult to identify the best measures to use.
According to national research, work zone speed limit reductions of more than 10 mph show an increase in crashes due to a wider speed differential between vehicles (WSDOT 2009). In response to concerns about speed through work zones, the ODOT Director requested (via the Associated General Contractors Oregon-Columbia Chapter and the Oregon Trucking Association) to have ODOT look at interstate preservation job safety enhancements. The request (Summer 2011) was to assess the practicality and effectiveness of reducing speeds from 55-65 mph to 35 mph under these specific conditions.
As an initial step, ODOT conducted a pilot study in September 2011 to investigate practical and safe means for significant speed reductions. The pilot study was conducted on Interstate 5 near Cottage Grove. The traffic control plan included a 30 mph speed reduction from 65 to 35 mph implemented in two stages (65 to 50 mph, then 50 to 35 mph) using multiple OSP officers and other traffic control measures along the roadway prior to and within the work area. This strategy is similar to the use of a system of stepped speed limits (SSL) that was recently studied and recommended in the U.K. (ITS International 2011). On the pilot study, with Law Enforcement visible, passenger vehicle speed measurements through the work zone showed a mean speed of 33.0 mph for cars (n = 108 vehicles; 85th percentile speed = 36 mph; 22% of cars exceeding posted speed). For trucks, the mean speed was 33.23 mph (n = 145 vehicles; 85th percentile speed = 36 mph; 19% of trucks exceeding posted speed).
Current research on controlling and reducing speeds on high-speed roadways, and on significant speed reductions, provides limited guidance. In a study of speed reduction measures conducted by Iowa State University on behalf of the Iowa Department of Transportation, the authors state the most effective speed reduction will probably involve some combination of speed reduction techniques, as opposed to the use of just one type of control measure (Maze et al. 2000). The researchers in Iowa conducted a survey of state transportation agencies and found that only a few agencies even consider reducing speed limits by 20 mph or more. The study also revealed that the use of regulatory speed limit signs and police enforcement are the most common practices for controlling and reducing speeds.
Due to the limited nature of the pilot study and the gap in current literature, further study is needed. ODOT would like to study possible strategies to safely reduce speeds and subsequently improve the overall safety of the work zone – for drivers, passengers, and workers. The proposed research is intended to augment the pilot study and provide additional data necessary to confidently make practical conclusions and recommendations to ODOT for significant speed reductions.
OBJECTIVES: The overall goal of the research is to assist ODOT with enhancing the safety of motorists and workers in construction work zones on high-speed roadways. To do so, the research aims to examine the reasonableness and ability to reduce traffic speeds through specific pavement preservation project work zones by as much as 30mph per the AGC’s request; and, if such speed reductions are found to be acceptable and practicable, to develop guidance for implementing significant speed reductions through targeted engineering practices. Work zone design guidelines, such as the Manual of Uniform Traffic Control Devices (MUTCD) and the ODOT Traffic Control Plans Design Manual, have been developed that guide the design and implementation of the wide variety of available traffic control devices. Using this knowledge and the results of the pilot study as a starting point, the research will attempt to identify those traffic control practices and designs that are especially effective at reducing speeds by a significant amount and that are also cost effective, safe to implement, not disruptive to the construction work, and not a significant impediment to traffic flow.
The research will focus on effective means to reduce actual speeds in work zones. This includes methods to safely reduce legal posted speeds as well as find measures that reduce actual speed without relying on a posted speed reduction. Research products may include advanced traffic control plans and guidelines for police activities under these conditions.
IMPLEMENTATION: The outcomes of this research study will be implemented by the ODOT Traffic and Roadway Engineering Section through procedures outlined for the Region Tech Centers by Robert Bob Pappe, State Traffic-Roadway Engineer. The outcomes will also be implemented by the Statewide Construction Office on similar preservation projects through communication and education of the statewide Construction Project Managers as approved by Jeff Gower, Statewide Construction and Materials Engineer. The results will be used by the Transportation Safety Division through the request of police agencies participating in these types of projects and by the Region Transportation Safety Coordinators in each Region through contact with the police agencies providing enforcement efforts.
WORK PLAN
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Proof of Concept; GTFS Data as a Basis for Optimization of Large Scale Transit Networks | Project Coordinator |
Lyn Cornell |
| Research Agency: |
Oregon State University |
| Principal Investigator: |
David Porter/David Kim |
| Start Date for ODOT: |
July 9, 2012 |
| Completion Date for ODOT: |
December 31, 2013 |
BACKGROUND: The research focus area, General Transit Feed Specification (GTFS), defines a common format for public transportation schedules and associated geographic information. The GTFS was developed cooperatively between Google and Portland TriMet [1]. Using the GTFS, a public or private agency can describe such characteristics of their transit network as service calendar, stop times, stop locations, trips (two or more stops) and routes (collection of trips), to name a few, so that it can be used in applications that present public transportation information in space and time. The GTFS data is also analyzed by transportation planners and researchers. Many transit agencies in the U.S. (and across the world) have already created and adopted the GTFS data standard to make information about their network available to users [2]. In Oregon, roughly 75% of fixed route transit providers have GTFS data for their services [3] and it is anticipated that the State’s entire fixed route transit network will be described by GTFS data within a year.
According to ODOT’s Public Transit Division (PTD) the majority of investments made in transit service by state, local, and federal government agencies are based on local service providers’ individual priorities, made with limited ability to consider the impact that these investments may have on the larger transit network. ODOT is also lacking in a tool to use the GTFS data to understand and assess gaps in spatial and temporal transit schedule connectivity, and correlate this information to analyze the performance of the larger state or regional transit network to the population of the state.
OBJECTIVES: The main objective of this project is to take advantage of the immediate opportunity that the available GTFS data presents to develop a better understanding and more efficient utilization of existing state-wide and region-wide transit networks. This project will develop a prototype computer-based tool (or tools) that can receive this data, and structure it to analyze and report on the Oregon transit network, as described by GTFS data. The proposed Transit Network Analysis (TNA) computer-based tool(s) will be web-based, stand-alone solutions.
IMPLEMENTATION: Results of the design, development, testing and validation of the TNA web-based tool(s) will be documented in the final report for ODOT Research. The results of the project may also be presented at relevant transportation related conferences and submitted in the form of journal/conference articles to appropriate journals.
PTD will support continued operation and maintenance of the TNA web based tool(s). PTD partners will be invited to use and test the TNA web based tool(s). Over time PTD will increase the pool of users with access to the tool (ODOT staff, local transit agencies, planners, etc.). PTD expects to invest in extending the TNA web based tool(s) capabilities.
The TNA web based tool(s) is expected to provide input to investment decisions, performance measures, provide information that is aligned with the new PTD regions, and support the addition of transit data to the Oregon Communities Reporter tool.
PROOF OF CONCEPT; GTFS DATA AS A BASIS FOR OPTIMIZATION OF LARGE SCALE TRANSIT NETWORKS WORK PLAN Quarterly Reports:
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Transportation Performance Measures for Statewide Outcomes-Based Management | Project Coordinator |
Myra Sperley |
| Research Agency: |
Cambridge Systematics |
| Principal Investigator: |
Steven Pickrell |
| Start Date for ODOT: |
July 26, 2012 |
| Completion Date for ODOT: |
March 31, 2014 |
BACKGROUND: ODOT has, for many years, recognized the importance of collecting data to better manage aspects of our transportation system. Data is valued for its potential to assess the condition of assets, understand the performance of the system, and to project potential outcomes of different investment choices. Many of the performance measures that ODOT analyzes and reports on are used by individual units or sections but have the potential for broader applications, and others may be useful in tracking progress but do not provide the right type of information necessary to help make decisions. As a whole, these measures do not currently function together to draw a clear picture of how the transportation system is functioning. One place where is this apparent is in ODOT’s Key Performance Measures, which do not provide decision-making support, nor are they entirely representative of the many important areas where ODOT is making progress in goal areas. For example, under the goal, “sustaining the environment and communities” the two performance measures are the number of priority culverts that need work to improve fish passage and the percent of urban state highways with bike lanes and sidewalks. Not only do these measures speak to a very limited portion of the work ODOT is doing in this area, but they also do not provide sufficient information for decision making.
This system information is vital for a number of reasons. It can help guide investment decisions; it can inform performance-based and strategic planning efforts and it can also help ODOT better communicate to both the public and other government agencies about our achievement towards a variety of goals such as mobility, reliability, freight and livability. One specific call for this work can be seen in Governor Kitzhaber’s 10 Year Plan for Oregon that includes a 10-year budget plan. For this work, each state agency is charged with identifying their contributions toward achievement in outcome areas such as healthy environment, safety, and education. However the need to report in these and similar areas is not isolated to the 10 Year Plan effort, but performance indicators are also being examined as part of the USDOT reauthorization and through the FHWA Performance-Based Planning and Programming project and may be tied to funding. To support this work, a coordinated effort is needed to bridge existing performance measures together, identify potential new measures and the data needed to support them, and evaluate how they link to ODOT’s goals and the 10 Year Plan for Oregon’s outcome areas.
This research project will build on existing efforts within the agency (e.g. alternative mobility measures research, safety performance measures, and Least Cost Planning / Mosaic) to identify decision making performance measures, outcome based performance measures, and consideration of other strategic planning measures, seeking to identify those indicators most informative, measurable, and consistent.
OBJECTIVES:
o Identify opportunities for current performance measures to better address outcome areas through improvements to data collection and analysis methods.
o Examine potential new performance measures that could assist ODOT in communicating achievements in proposed outcome areas.
Recommend a set of performance measures, which presumably would be a combination of existing measures and possible new measures, as well as improved/enhanced data collection, analysis and reporting methods that help to get the most benefit out of existing measures and that make possible the new measures which are better aligned with outcome areas and provide better support to decision making. IMPLEMENTATION: This work will result in a recommended set of performance measures, what outcomes they support and the data stipulations required for use. Avenues for implementation include use as indicators for the Governor’s 10 Year Plan for Oregon, modifications to ODOT’s Key Performance Measures, as well as better system information that will assist in strategic planning and investment decisions.
WORK PLAN Quarterly Reports:
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Design and Implementation of Pedestrian and Bicycle-Specific Data Collection Methods in Oregon | Project Coordinator |
Lyn Cornell |
| Research Agency: |
Portland State University |
| Principal Investigator: |
Miquel Figliozzi/Chris Monsere |
| Start Date for ODOT: |
August 1, 2012 |
| Completion Date for ODOT: |
March 31, 2014 |
BACKGROUND: As a policy objective, increasing pedestrian and bicycle mode shares has a number of desirable outcomes, ranging from reduced congestion and infrastructure costs to improved air quality and population health. Recent estimates from the 2006-2010American Community Survey indicate that of the 1.7 million workers in Oregon, 2% commute to work by bicycle and 3.9% by walking–though the rates are much higher in specific cities for bicycling (e.g. Corvallis – 6.5%, Eugene – 4.3%, Portland – 3.7%, Medford– 3.4%) and walking (e.g. Astoria – 6.5%, Brookings – 6.9%, Ontario – 5.0%). To attract additional pedestrians and cyclists, the literature suggests that infrastructure improvements to improve safety, connectivity, and comfort are needed[1].Data are instrumental to demonstrate results and support cost/benefit analysis for these investment decisions.
At ODOT and most local transportation agencies, there is extensive experience, equipment, and procedures to collect and analyze continuous and short duration motorized vehicle count data. These data have many valuable uses for the transportation agencies that collect them to support safety, forecasting, and performance monitoring activities. This is not the case for non-motorized travel. A growing number of city, county, and state staff are expressing interest and requesting pedestrian and bicycle count data to properly design improvements on sidewalks, crosswalk, cycle tracks, bike boxes, and signalized traffic crossings (green time allocation, pedestrian and bicycle-specific signals, dedicated signal phases). In addition, non-motorized volume data are needed to evaluate the performance of new investments, as input for new safety analysis tools used in the AASHTO Highway Safety Manual, to inform health assessments, and to assess multimodal transportation trends.
The most common source of non-motorized data is volunteer counts taken for short duration periods, usually for 1-2 days, as part of the National Bicycle and Pedestrian Documentation Project. Unfortunately, volunteer data collection efforts are too sporadic and unsystematic to address ODOT data needs for traffic, safety, or design studies. Thus, current data sources are not even able to provide a clear picture regarding pedestrian and bicycle trip trends at the corridor level. Permanent data collection efforts are limited to a few major facilities that are bike-accessible and more often on recreational trails.
Methods for strategically locating permanent count locations to identify appropriate groupings and factoring values have not been developed for Oregon. Research and experience suggest these values will have significant time-of-day, seasonal, facility, and geographic variations. For example, data from existing permanent data in urban areas indicate that peak pedestrian volumes take place at midday and do not coincide with peak motorized traffic volumes. There are important data gaps and there is a clear need for this research. A review of the literature indicates that similar research and implementation of pedestrian and bicycle-specific data collection are taking place in other states (e.g. Colorado and California) but not in Oregon[2][3][4]. The ODOT Bicycle and Pedestrian Travel Assessment (PTA) report, released in July 2011, recognizes the need to enhance and implement bicycle and pedestrian data collection plans in Oregon [6]; in particular, the PTA report recommends that data collection efforts should concentrate on roadways with less emphasis on trails.
OBJECTIVES: This proposal focuses on research and evaluation of pedestrian and bicycle available collection methods, data retrieval and storage, and data analysis. The outcome of this research will be a plan for long-term implementation and data collection guidance. The implementation plan will identify a minimum level of hardware placement to start the program and how to invest in data collection over time as resources become available. The data collection plan will include recommendations and guidelines regarding data collection procedures, temporal and spatial sampling, and factoring methods to adequately capture weather and seasonal effects and/or daily/hourly variations of pedestrian and bicycle volumes. The outcomes of this research respond to recommendations recently made in the ODOT Bicycle and Pedestrian Travel Assessment Report [6]. The primary emphasis of this research will be placed on collecting data on bicycle and pedestrian trips on or near roadways and multi-use paths that serve a transportation purpose.
IMPLEMENTATION:
The results of this research will be directly incorporated into the ODOT Pedestrian and Bicycle program. Other jurisdictions, such as metropolitan planning organizations and other cities, would also be able to incorporate results of this research into their local programs. Research results would be used by ODOT Planning, Design, Traffic Operations and Project Delivery work groups to inform their work. As data sets develop the ODOT Crash Analysis and Reporting Unit and Transportation Safety Division could incorporate data to develop crash rate information for non-motorized travel, a significant improvement over current methods. The ODOT’s Bike/Ped Data Working Group would use the results of this research to make recommendations about next steps in data collection and analysis.
DESIGN AND IMPLEMENTATION OF PEDESTRIAN AND BICYCLE-SPECIFIC DATA COLLECTION METHODS IN OREGON WORK PLAN
Quarterly Reports:
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Performance Based Selection of RAP-RAS in Asphalt Mixtures | Project Coordinator |
Norris Shippen |
| Research Agency: |
Oregon State University |
| Principal Investigator: |
Chris Bell |
| Start Date for ODOT: |
October 4, 2012 |
| Completion Date for ODOT: |
February 28, 2014 |
BACKGROUND: The price of petroleum products is expected to continue increasing in the future, and, without funding increases, ODOT is looking at a period of significantly reduced investment in the highway system. ODOT currently uses recycled asphalt materials (RAM), which are is typically recycled asphalt pavement (RAP) and recycled asphalt shingles (RAS), to help reduce the costs. The current limits on RAM are restricted based upon local and national experience. However, ODOT is interested in allowing for more innovation and optimization of mixtures including recycled materials. The intent of this study is to use performance based tests to evaluate mixtures with increased RAM content, resulting in minimizing the potential cost, and providing environmental and performance benefits.
ODOT currently allows the use of RAM in its HMAC without any adjustments to the virgin binder grade. The effect of the recycled asphalts on the final binder grading is unknown. This may lead to a HMAC product that is more susceptible to early fatigue or thermal cracking. This study will also evaluate approaches to evaluate the selection of appropriate binder grade.
OBJECTIVES: Guidelines will be developed for selecting RAM content by using binder and mix performance criteria. A study will identify binder and mix properties related to cracking and permanent deformation. Acceptable properties will be established by an evaluation of a range of lab produced mixtures, with subsequent validation by trial projects and testing of plant produced mix. In the absence of a full suite of performance tests, blended binder properties targets could be the criteria, however the ultimate goal will be to establish minimum criteria for mix properties with particular focus on how to determine the impacts on age related, cold temperature and fatigue cracking.
Appropriate triggers will be developed for virgin binder replacement percentages and/or base binder grade changes to accommodate the effects of the RAM and develop a RAM QC/QA testing program if the research justifies it.
IMPLEMENTATION: The research will result in guidelines for RAP/RAS and binder selection that will optimize the utilization of RAM in asphalt mixtures by optimizing the performance of such mixtures. Processes will be based on evaluation of plant and lab produced mixtures. A QC/QA testing program will be developed if the research justifies it. Implementation will be done by ODOT’s Pavement Services Unit.
PERFORMANCE BASED SELECTION OF RAP-RAS IN ASPHALT MIXTURE WORK PLAN Quarterly Reports:
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Improved Safety Performance Functions for Signalized Intersections | Project Coordinator |
Mark Joerger |
| Research Agency: |
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| Principal Investigator: |
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| Start Date for ODOT: |
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| Completion Date for ODOT: |
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BACKGROUND: To identify, prioritize and address safety needs requires an understanding of the complex interactions between the elements of roadway design, infrastructure, and traffic. This is particularly true in an environment of limited funding, since large scale improvements will be increasingly difficult to implement and lower cost targeted solutions will be more the norm. Tools available in the recently published AASHTO Highway Safety Manual (HSM) are helping ODOT staff complete the analysis needed to identify solutions suitable to address the causes of crashes.
Due to the high percentage of crashes occurring at signalized intersections considerable attention is given to selecting the improvements that result in the greatest reduction in crashes for dollars invested. ODOT has been researching the data needs and implementing the HSM within current procedures when possible but has identified limitations that affect the reliability of the results.
The HSM includes Safety Performance Functions (SPFs) to assess options for improving the safety of intersections. These are equations that use traffic volumes and other factors to predict crash reductions for various types of improvements. Since the SPFs do not allow for certain features such as turn lanes and lane widths, Crash Modification Factors (CMFs) can then be used to adjust the results of the equations to allow for these factors. However, currently these tools do not include consideration of approach speeds which are known to affect the frequency and severity crashes. The initial predictive models upon which the HSM procedure is based focused on rural two-lane highways and the approach speed at those intersections was not deemed to be significant. This foundation work then was used to define the SPF format for future models for the first edition of the HSM, so speed was inadvertently excluded in subsequent studies.
The question of including speed in the SPF process is frequently raised by the engineering community. This research will determine the safety impact of different speeds on the approach to a traffic signal. An assessment of this value in Oregon could likely help establish a new protocol that future editions of the HSM may incorporate for signalized intersection location models.
ODOT has also found that limitations in the traffic volume estimates for minor roads during peak and off-peak periods affect the quality of the analysis. The research will address this as well.
OBJECTIVES: The objective of the research is to develop more reliable ways to assess signalized intersection safety in Oregon so that ODOT and other agencies can allocate funding resources towards effective intersection safety configurations for both new and existing facilities. This will be done by developing signalized intersection safety performance functions that explicitly consider approach speed as a direct input in safety assessment of the location.
IMPLEMENTATION: Doug Bish, Traffic Services Engineer in the Traffic-Roadway Section will be responsible for implementation of the results. The materials developed in Task 6 will be incorporated into the Safety Investigations Manual (SIM). The results of the research will be integrated into spreadsheet tools for intersection alternatives using SPFs that will be included in the SIM.
WORK PLAN Quarterly Reports:
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Bluetooth Data Collection System for Planning and Arterial Management | Project Coordinator |
Mark Joerger |
| Research Agency: |
Oregon State University |
| Principal Investigator: |
David Kim |
| Start Date for ODOT: |
August 20, 2012 |
| Completion Date for ODOT: |
March 31, 2014 |
BACKGROUND: The transportation models and project level analysis work that ODOT’s Transportation Planning and Analysis Unit (TPAU) accomplishes have significant challenges that include the sheer quantity of data needed, the need for high accuracy, and significant data collection costs. For example, license plate surveys which are used for collecting Origin-Destination data typically cost from $10,000-$25,000 with much of the cost associated with matching plates/vehicles. The collection of travel time data used for simulation models and intersection performance evaluation is often completed by consultants at considerable expense. Additionally manual data collection primarily focuses on vehicle counts and delays while other data such as deceleration and acceleration for vehicles approaching and leaving intersections has largely been unavailable even though it has safety and signal timing applications. Travel time data is also needed by Region Traffic staff to monitor, evaluate, and maximize the performance of advanced traffic signal systems and to compare the performance of arterials.
OBJECTIVES: An OSU research team has completed research that, in conjunction with a software application in development (to be completed this spring), will allow ODOT’s ITS Unit to monitor transportation system travel times and provide more complete and timely traveler information to the public at a low cost. The research proposed in this problem statement will build on this completed research and more fully explore how wireless technology can be used to support planning and traffic operations data collection and analysis needs. The objectives of this project are:
- Utilize prior research experience to develop an inexpensive, easily deployed portable system for wireless automatic collection of vehicle movement data.
· Use this prototype wireless data collection system to complete Origin-Destination study data collection and assess how model results compare to results when using estimates from traffic counts or expensive license plate surveys.
· Utilize the system to collect data for simulation models and assess if this recent travel time data generates useful differences when compared to standard practice “data” when recent travel time data is not available.
· Apply the system at an intersection to monitor intersection performance and collect vehicle approach and departure acceleration data.
- Evaluate the use of the proposed system to collect travel time data needed for project level analysis to monitor, evaluate, and maximize the performance of advanced traffic signal systems; and compare the performance of arterials.
- Assess the effectiveness of the system to identify pedestrians, bicycles, and vehicles based on movement data patterns.
IMPLEMENTATION: The products of this research will be a complete portable system (for collecting vehicle movement data over road sections of interest (e.g., intersections, corridors, etc.). A system will consist of prototype DCUs that communicate and work together, and off-line software that can be used to automatically process collected data.
Additional products of the research will be the results of field studies on the collection and processing of data for various needs. This will help to identify the potential for Bluetooth data collection systems and their limitations.
The Technical Advisory Committee (TAC) for this project will include ODOT staff responsible for conducting the planning and analysis activities that will benefit from the research. ODOT staff involved in traffic signal systems implementation and monitoring have agreed to participate on the TAC as well.
The ODOT implementation champions are Brian Dunn, Manager of the Transportation Planning and Analysis Unit and Doug Bish, Traffic Services Engineer, Traffic-Roadway Section.
BLUETOOTH DATA COLLECTION SYSTEM FOR PLANNING AND ARTERIAL MANAGEMENT WORK PLAN Quarterly Reports:
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Width of Filter Strips for Natural Dispersion of Stormwater in Western Oregon | Project Coordinator |
Matthew Mabey |
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BACKGROUND: Infiltration is being emphasized as an important technique for managing stormwater. Dispersion of highway runoff in roadside filter strips or separate dispersal areas is a cost effective stormwater management technique that provides both water quality and flow control benefits. Determining the width of the dispersion area needed to infiltrate the design storm is necessary to identify the amount of right-of-way needed and if additional BMPs are required. Washington DOT has two methods for determining the width, one based on roadway width, saturated hydraulic conductivity and rainfall intensity (called the “LID Design Equation”), and the other a rule of thumb based on soil characteristics. The first method is approved by WSDOT only for eastern Washington, while the second has general applicability. Given the similarities in climate, using the first method in central and eastern Oregon seems justified. However, the second method is quite coarse, and could overestimate the necessary width of the dispersion area in western Oregon. Among other things, second method has a large discontinuity in width requirements between soils with less than and greater than 4 in/hour saturated hydraulic connectivity rates. Research to establish an equation for sizing dispersion areas in western Oregon is needed.
OBJECTIVES: The objective of this research is to expand the data set and understanding of Washington’s LID Design Equation” to the point that an equivalent design approach that is applicable to western Oregon can be developed. IMPLEMENTATION: The research would produce a design procedure for sizing the width of dispersion areas. Included would be identification of the factors considered in the procedure, guidance on the acquisition of necessary information, any equations to be used, and the steps for implementation and interpretation of results. The design procedure would be first released as a Technical Bulletin for distribution, to be followed by inclusion in the ODOT Hydraulic Design Manual. The Geo/Environmental Section would be responsible for developing and releasing the Technical Bulletin and Hydraulic Design Manual update.
DETERMINATION OF THE APPROPRIATE WIDTH OF FILTER STRIPS FOR NATURAL DISPERSION OF STORMWATER IN WESTERN OREGON WORK PLAN Quarterly Reports:
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Capturing Multimodal Comparisons in Freight Project Prioritization
| Project Coordinator |
Lyn Cornell |
| Research Agency: |
University of Washington & OSU |
| Principal Investigator: |
Anne Goodchild and Starr McMullen |
| Start Date for ODOT: |
September 25, 2012 |
| Completion Date for ODOT: |
March 15, 2015 |
OVERVIEW
Existing tools used to compare multi-modal investments are not sufficient to measure their economic and environmental impact or accurately evaluate tradeoffs between modes. Previous studies resulted in identifying new and supplemental multimodal freight investment criteria, including the ConnectOregon program, but did not identify any methodologies for prioritizing multimodal investment projects using these criteria.
OBJECTIVES
Previous work has identified the need to evaluate the impact of a modal project on other modes, but failed to describe how existing tools (if any exist) would perform the calculations and any inconsistencies between modal calculations that might affect comparisons. This project will develop a methodology to make comparisons across modes for use in intermodal comparison purposes and it will clearly identify the analytical gaps, and where possible, make recommendations for feasible solutions.
CAPTURING MULTIMODAL COMPARISONS IN FREIGHT PROJECT PRIORITIZATION WORK PLAN
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