NCHRP Project 08-127 Emerging Issues: Impact of New Disruptive Technologies on the Performance of DOTs
Research Field: Transportation Planning, Source: AASHTO Committee on Performance-Based Management
Allocation: $250,000, NCHRP Staff: Lawrence D. Goldstein
The transportation of people and goods is one of the most important components of our everyday lives. The arrival of the 4th Industrial Revolution and the rapid development and fusion of multiple disruptive and innovative technologies, such as artificial intelligence, big data and digitization, the Internet of Things (IoT), fifth (and even sixth) generation wireless technologies (5G/6G), connected and autonomous vehicle (CAV) technologies, on-demand ride-sharing services, Mobility as a Service (MaaS), 3D print-ing, the sharing economy, and others are changing not only the behavior but also the expectations of both customers and stakeholders.
The fusion of these technologies is bringing a technological revolution that will fundamentally alter the way we live, work, and relate to one another. In its scale, scope, and complexity, the transformation is moving at a pace beyond which many governmental entities are equipped to respond. Mobility as we know it, is also transforming as new technologies disrupt traditional ways people and goods move throughout our transportation systems. The rapid introduction of mobile internet is upending the traditional approaches with new customer-centric business models based on the sharing economy such as online car hailing, bike sharing, time sharing, customized shuttle bus, parking sharing, etc. And while the new business models bring more convenience and efficiency to the users and to the national and local economies, they have also created new problems, needs, and challenges that we must face as decision makers. Today during the 4th Industrial Revolution as technology previously foreign to transportation rapidly enters old ways of doing business – e.g., solely road infrastructure related – performance is affected across all modes and aspects of transportation agencies’ responsibilities. Institutional processes may be knocked down to make room for updated or more effective methods to improve performance outcomes. Unfortunately, all agencies lag behind to at least some extent as they struggle to define meaningful measures, manage data collection, maintain accountability, and streamline reporting.
Disruptive technologies are forcing global changes that are capturing the attention of transportation agency leaders within AASHTO as well as transportation researchers worldwide, including the World Road Association (PIARC) that has recently announced a call for papers on the “Impact of Disruptive Technologies to the Performance of Transport Administrations” as part of the World Road Congress in Abu Dhabi in 2019.
The objective of this research is to advance our understanding of the potential impacts that innovative and disruptive technologies, including the sharing economy, will have on the overall performance of DOTs and MPOs. The research will seek to identify leading performance indicators that transportation agencies can use to improve their understanding of the possible impacts of these evolving technologies and how these changes might affect strategic planning and service delivery.
Agencies that adopt new processes and methodologies developed through this research project will benefit by:
- understanding the impacts of technology on the DOTs/MPOs performance;
- having a defensible framework for defining performance measures tied to goals of the agency;
- identifying the workforce skills needed for performance management capable of responding to advances in technology;
- being proactive in adapting business models and processes that respond to changes in transporting people and goods; and
- improving access, mobility, confidence in new technology, and safety for all users, including underserved populations.
Project 08-130: Best Practices in Coordination of Public Transit and Ride Sharing
Research Field: Transportation Planning, Source: AASHTO Council on Public Transportation
Allocation: $250,000, NCHRP Staff: Velvet Basemera-Fitzpatrick
Public transportation has long been the mobility alternative to single occupancy vehicles, offering a consistent and reliable method of ridesharing. However with the rise of private sector ridesharing companies and multimodal transportation options increasing, the interplay between traditional models and innovative approaches is critical to research, address, and engage with, in order to create a seamless transportation network that meets the mobility needs for all riders.
Online and phone mobility apps are becoming increasingly available in small urban and rural communities to help people find the best commuting option to shopping, appointments, recreation, employment, and other destinations. These apps make it easy to find the best transit route, locate a park and ride lot, map your trip, or even find a commuting partner based on your work schedule or neighborhood. However, many small urban and rural communities lack these online tools, leaving commuters, especially those without automobiles, to navigate the complexities of the transit systems in these areas, highlighting the needs to research solutions to the existing gap in transportation coordination amongst the growing options.
The objective of this research is to document the available online apps to help ease commuter access to public transit and allow for improved mobility in their communities. In order to advance this area of transportation knowledge, it is important to identify what existing resources are currently available and if/ how the private industry is interacting and partnering with the public sector in coordinating mobility services. As one of the Idaho Transportation Department’s (ITD’s) core mission statements, “Your Mobility”, researching and understanding the opportunities to coordinate public transportation with other ridesharing mobility options directly ties back to the focus areas in this state. As the mobility needs are changing, and the gap in design between rural transportation and urban transportation increasing, we are at a critical juncture in need to innovative solutions. The outcomes that this project will be able to be implemented in the form of marketing efforts, outreach strategies, and provide data and analysis to bring together multiple stakeholders with a common goal.
Project 08-131: Access to Jobs, Economic Opportunities, and Education in Rural Areas
Research Field: Transportation Planning, Source: AASHTO Council on Public Transportation
NCHRP Staff: Lawrence D. Goldstein
Populations across the country are shifting, creating a need for stronger connections to rural areas. These connections might be rural-to-rural or rural-to-urban. Population shifts have created challenges for employers in rural areas and their ability to expand and recruit additional employees. Moreover, jobs in our urban areas are not paying adequately, and increasing access for populations in rural areas to jobs in rural communities is important to their success. Transit plays a necessary role in traditional and non-traditional models in helping to solve this employment shortage.
The objective of this research is to identify specific needs in rural communities, including employment, education and transportation, and explore the range of new relationships and partnerships needed to improve access, not only to jobs and education, but also to other necessary community services. While many jobs, education institutions and medical facilities will be located in metropolitan regions, major employers supporting economic prosperity will also be located in suburban and rural areas. Commuting patterns will become increasingly regional, requiring transit agencies to develop new services to connect employees across jurisdictional boundaries. New local routes, regional commuter services and rural routes facilitating access to employment will support sustainability and growth to regional and statewide economies. This process represents a paradigm shift away from looking at jurisdictional–based planning, looking instead at larger geographic area needs or travel sheds to meet those needs.
Project 08-132: Accessing America’s Great Outdoors: Understanding Recreational Travel Patterns, Demand, and Future Investment Needs for Transportation Systems.
Research Field: Transportation Planning, Source: AASHTO Special Committee on Research and Innovation/Committee on Planning/Tennessee
NCHRP Staff: Lawrence D. Goldstein
Each year, there are an estimated 870 million visits to federal lands (Leggit et al. 2017). This recreational and tourism travel, driven by demand for access to parks and public lands, continues to increase in urban and rural areas throughout the country, placing new and changing demands (traffic congestion, air pollution, etc.) on transportation systems. Managing this travel demand has been increasingly challenging and has added congestion and operational stresses on not only the public lands themselves, but also on the gateway communities that provide access to them. For example, many National Parks have seen substantial and rapid changes in visitation rates over the last five years (as high as 40% and 60% at some units) and looking ahead, the growth rate for international visitation to the US is higher than the forecast growth for domestic travel (according to the US Travel Association). This growth in visitation has resulted in congested roads, intersections, and entry gates for many parks as well as gateway communities (c.f. Yellowstone Transportation and Visitor Mobility Study 2016; Acadia Transportation Plan / DEIS 2017).
In many places we are seeing tourism expand at record breaking numbers. For example, tourism to Utah grew 12 percent from 2011 to 2015, with visitors spending a record of nearly $8.2 billion and generating approximately $1.15 billion in total state and local tax revenue. This visitation expansion is happening both in total visitation numbers, but also in traditionally low use seas seasons. For example, NPS visitation grew 9% in September 2018 when compared to the same month last year. Outdoor recreation contributed $373.7 billion to the US economy (or 2%) in 2016, exceeding the economic contributions of other industries that access similar lands (e.g., mining, oil, and gas extraction at 1.4% of total GDP) (BEA ORSA). The outdoor recreation economy grew 3.8 percent in 2016, compared with the overall U.S. economy’s 2.8 percent growth that year. Many local communities in rural areas are largely dependent on the recreation travel economy.
As a result, there is a real need for increased research in understanding recreational travel demand, patterns and demographics. Changing consumer preferences and evolving travel decision-making will affect tourism in the future. Without information to help understand and predict these trends, land managers, states and gateway communities are limited in their ability to make equitable transportation investment decisions about access, quality and asset management within a single jurisdiction, and especially within multiple jurisdictions. A goal among several federal departments to enhance the recreation and tourism (e.g., DOI SO 3366, USDA Call to Action #5) means that agencies at all levels need to collaborate and find sustainable solutions to managing recreational travel demand generated by public land visitation. Proactive and strategic investment in the as-sessment and planning for visitor use management along recreational travel routes is needed to support both federal and state efforts to successfully manage changing visita-tion, connect visitors to public spaces, protect resources, support local economies and provide for high quality travel experiences; however, most (if not all) travel demand models use tools and assumptions that do not account for the unique needs, uses and pat-terns of recreation-based travel.
To address this need, this study has three primary objectives: 1) to document and de-scribe recreational and tourism travel demand and the related data gap within key states of interest (focus states TBD); 2) to identify and begin to explore which factors (economic, demographic, geographical, etc.) drive recreational travel volumes and patterns (both within and between public lands); and 3) to develop a model to project recreational travel demand on state and country roads to allow those jurisdictions to make better informed decisions about investments in economic development, transportation and other issues that may affect quality of life for residents and experience for visitors.
Project 14-43: Guide Construction Specifications for Cold In-place Recycling (CIR) and Cold Central Plant Recycling (CCPR)
Research Field: Maintenance, Source: AASHTO Committee on Maintenance
NCHRP Staff: Edward T. Harrigan
Pavement preservation is becoming an important activity for DOTs in maintaining and enhancing the condition of their highways. With the enactment of MAP 21 mandating that DOTs show improved performance in the condition of their highways, the use of pavement preservation treatments will be crucial to meet performance goals. Pavement preservation treatments are treatments that do not improve the structural capacity of a pavement but do delay pavement deterioration. Cold in-place recycling (CIR) and cold central plant recycling (CCPR) are considered minor rehabilitation pavement preservation treatments when the recycled layer is topped with a thin overlay. They can treat cracks of a higher severity than other preservation techniques can and topping the recycled layer with a thin overlay modifies the pavement structure to produce a more long-lasting system. CIR and CCPR treatments are part of a sustainable strategy for reducing the need for new aggregate and new asphalt while using lower energy and creating fewer emissions.
Preservation treatments using asphalt emulsion as the binder have almost always been considered secondary to hot mix asphalt (HMA) technologies and are therefore not as well understood. These technologies have not been upgraded or researched to the extent that HMA has. However, over the last five years the FHWA PPETG (Pavement Preservation Expert Task Group) and ETF (Emulsion Task Force) have made a concerted effort to (1) improve the state of the science in emulsion technology and (2) create consistent performance-based standards (specifications, test methods, design practices, etc.) that are sponsored by FHWA and AASHTO and are not vendor specific.
The rationale for creating AASHTO standards for pavement preservation treatments is to provide credence, and more importantly, buy-in from the DOTs. In order to implement any of these treatments in construction projects, both material and construction standards must be first created, and in the case of CIR and CCPR, a mix design practice and material specifications have been developed and submitted to the AASHTO Sub-committee on Materials (SOM). However, as noted in NCHRP Synthesis 421, one of the barriers to greater use of these treatments is lack of specifications. Development of guide construction specifications accounting for the best practices by agencies and contractors will greatly assist in increased use of these treatments, especially by agencies with little experience with in-place recycling.
The objective of this research is to produce an AASHTO Construction Guide Specification for the application of CIR and CCPR. This guide specification will assist highway agencies to tailor their own specifications to the local conditions and environments and go far towards getting DOTs to implement such treatments in their pavement preservation programs. Accomplishment of this objective shall include a task to review (1) previous work in this area and (2) construction specifications and practices that are in use in several state DOTs already using CIR and CCPR.
Project 23-04: Cost–Savings Analysis of Statewide Insurance Pooling for Public Transit
Research Field: Soils and Geology, Source: AASHTO Council on Public Transportation
NCHRP Staff: Velvet Basemera-Fitzpatrick
Transit agencies are finding it increasingly difficult to locate, purchase, and maintain adequate and affordable insurance coverage for public transit vehicles. Not only is the cost of adequately insuring all the vehicles in every transit agency increasing, but the ability to cover costs for each agency’s individual policy premiums is a challenge as well.
Last year, across-the-board increases in premiums with identical coverage affected all transit providers, especially rural transit providers where the increase was a sizable part of their annual programming. Additionally, the number of smaller insurance agents is decreasing due to the volatile nature and demands of the insurance industry, and insurance coverage requirements in general. Finally, small rural transit agencies often face the largest cost increases due to their small fleet sizes and high annual mileages per vehicle. Since state departments of transportation either directly purchase the vehicle insurance policy or fund the transit provider’s vehicle insurance policies, this research will provide solution for states seeking to consolidate this practice and implement statewide insurance pools for insuring transit vehicles.
The objective of this study is to examine the types of insurance available to the transit industry for covering vehicles and explore the cost savings that could be realized with statewide insurance coverage for all the transit and paratransit vehicles in states. The study should also determine the percentage of insurance administrative costs that could be saved from this approach in comparison to the current individual providers subscribing to a separate policy coverage for fleets. Developing recommendations for implementing statewide insurance pools, including work plan, responsibilities matrix, and timeline to transition from single-agency insurance policies to state-level insurance pool plans.
Project 23-05: Addressing Construction Inspector Qualifications for the Future: Best Practices for Education, Training and Certification
Research Field: Administration, Source: South Dakota
NCHRP Staff: Ann M. Hartell
In recent years, state DOTs have faced increasing demands for Construction Inspection (CI) staffing due to a more technically and contractually complex construction project environment. This has been exacerbated by the retirement of the baby-boomer generation from the workforce and with them, their many years of experience. According to the Georgetown Center on Education and the Workforce, by 2020, 65 percent of American jobs will require some form of post-secondary degree or credential. The required skill set of the CI has also changed, requiring not only technical skills that have been in place for decades, but also the adaptation of those skills due to improvements in technology and differing forms of construction contracting, such as Design-Build and Risk Based Inspection.
In some states, construction volume has increased and/or the numbers of state employees has decreased, giving consultants a larger role in supporting state DOTs’ CI needs. The lack of a national standard for the required combination of skills, especially for consultant-hired inspectors, is a dominant factor supporting the need for research. State DOTs recognize that the performance of CI is necessary in order to fulfill policy directives of ensuring that projects under their jurisdiction are constructed in conformance with the state–and FHWA–approved plans and specifications. Consultant Inspection must be utilized to augment state DOTs’ workforce. However, outsourcing CI tasks to consultant inspectors presents specific challenges to state DOTs. One of the main challenges currently faced is the lack of a national standard for the skill set of consultant inspectors on the basis of validated formal education, experience and certifications.
The main objective is to identify activities and policies that have demonstrated a potential to ensure that inspectors possess the capabilities that will be required in the years ahead. This will be done by studying the current status of inspector capabilities and by benchmarking state-of-the-practice programs for the formal education, experiential learning, and certification of personnel:
• Existing Skills: Identify existing educational and career backgrounds, and levels of relevant skills of individuals who are entering their first CI jobs.
• Formal Education: Identify formal education and training programs for individuals entering CI positions.
• Certification: Identify programs that provide for the certification of an individual’s acceptable levels of appropriate CI skills.
• Experiential Learning: Identify programs that provide formal internships that combine education with on-the-job training and experience for individuals training to become inspectors.
• Quality: Identify programs that provide assured training, experience and certification of inspectors.
• Increasing Skills: Investigate inspector career pathways that result in increased capabilities, and the additional formal education, additional experience, and additional certifications that form the basis for the increased capabilities.
This study will assemble a national set of effective practices and develop reports, case studies, and guidelines that can be utilized by agencies to implement based on local statutory and/or policy requirements for the development and implementation of individual state CI formal educational, experiential and certification qualification programs and standards. The guidelines should include a methodology to compare existing program alternatives on a basis of both potential cost and time savings. It should also incorporate guidance that allows DOTs to be able to justify the costs of the proposed CI formal educational, experiential and certification qualification and development program alternatives on a basis of offsetting construction quality benefits.
A compendium of reports, case studies, and guidelines should allow implementation to be customized by each state DOT and private sector firm, while facilitating the portability of qualifications by CIs who perform inspection work for different agencies. This would enable utilization of common training and credentialing resources, which, in turn, spreads out the costs of those resources, while increasing the pool of expertise available for their production.
Project 23-06: Developing an AASHTO Guide to System–Level Asset Valuation in Support of Transportation Asset Management Decision Making
Research Field: Administration, Source: AASHTO Committee on Performance-Based Management
NCHRP Staff: Andrew C. Lemer
Return on assets is widely accepted as a measure of performance for asset management and investment analysis and is widely used as a basis for allocating scarce resources—money, for example—among diverse activities that may use those resources to produce desirable goods and services. State departments of transportation (DOTs) are stewards for public infrastructure assets that are essential to our economic vitality, public safety, and quality of life. Accurate, relevant, and reliable asset valuation is crucial for decision making to ensure the effective, efficient and economical management of our highway and transit assets.
The current federal highway statute (23 USC 119) and regulations (23 CFR 515) require state DOTs to develop a risk-based transportation asset management plan (TAMP) that includes a valuation of pavements and bridges on the National Highway System (NHS). State DOTs are complying with these requirements through various approaches, but have struggled to incorporate asset valuation into asset management practices or infrastructure investment decisions in a consistent, meaningful way. Practices used internationally for incorporating asset valuation into an organization’s financial statements have not been much used in the U.S. Some guidance has been produced (for example, the Federal Highway Administration’s (FHWA) report on Incorporating Asset Valuation into Transportation Asset Management Financial Plans; NCHRP Reports 483, 608, and 898), but detailed assessment of the issues and practical procedures for valuation and management for public-sector transportation assets in U.S. practice are needed.
The objectives of this research are to examine methods for valuation of system assets and to develop guidance and tools to demonstrate quantitative asset-level valuations for an agency. The research should (a) review various approaches for asset valuation, such as GASB34 and Depreciated Replacement Cost, with a focus on identifying whether current replacement cost or a market value approach should be used, how each is beneficial and can be incorporated into asset management plans and practices; (b) determine a baseline of existing practices currently undertaken by domestic and international highway and transit agencies to identify specific objectives for a standard asset valuation methodology, including case studies of successful implementation; and (c) develop a transportation asset valuation guide and methodology for U.S. transportation agencies, including a roadmap for implementation of appropriate valuation approaches into work planning and programming practices, practical examples that can be used by asset owners, system op-erators, and planning organizations to utilize asset valuation to improve the effectiveness of investments in transportation infrastructure.
Project 23-07: Guidebook for Identifying and Implementing Forecasting Techniques for Effective Target Setting
Research Field: Administration, Source: AASHTO Committee on Performance-Based Management
NCHRP Staff: Ann M. Hartell
In the Transportation Performance Management (TPM) framework, forecasting of performance is a key element in effective setting of performance targets. In the seven national performance goals defined by MAP-21 and its successive legislation, the established performance measures capture several dimensions of performance; reflect distinct and varied underlying processes that relate actions to outcomes; and are subject to varying degrees of influence by, and interaction with, factors and covariates affecting or driving performance. The forecasting of performance in this diverse context would benefit from techniques that are tailored to each particular context and business process designed to impact outcomes. Whereas asset management systems may be adept and sufficiently developed to predicting performance for pavements and bridges, other performance dimensions such as highway safety and system reliability may require different approaches. Consequently, there is a need to provide guidance to the performance manager in selecting a reasonable and effective approach for forecasting performance that is well suited to the specific performance dimension that is being managed. This need extends beyond specific national performance measures to all performance measures used by transportation agencies to monitor and positively impact outcomes in their sphere of influence.
Forecasting techniques have been developed in a variety of areas of human activity, in economics, social and natural science, and the technical and engineering fields, and there is an opportunity to draw on general principles to apply an appropriate forecasting methodology to transportation performance measures.
The objective of this research is to develop a guidebook for transportation performance managers to identify, select, and implement forecasting techniques that are appropriate for each performance measure. The guidebook should enable performance managers to identify general types of performance measures and pair them with the most promising methodologies for forecasting performance that will help achieve the goal of effective target setting. The guidebook should also treat the subject of secular changes in the phenomena being measured and how to address the impact of these unforeseen changes on the estimation of future outcomes using each of the forecasting techniques. The guidebook should also contain a step-by-step procedure that can be applied to any performance measure. It would be useful to include an actual forecasting example as a case study so that state DOTs have information about what kind of work is necessary after the guidebook has been used. For this purpose, existing national performance measures could be examined in the latter part of the research.
Project 23-08: Guidelines for Incorporating Maintenance Costs into a Transportation Asset Management Plan
Research Field: Administration
Source: AASHTO Committee on Maintenance
NCHRP Staff: Lawrence D. Goldstein
MAP-21 established a performance-based Federal-Aid Highway Program that includes a requirement for state transportation agencies to develop and update a risk-based Transportation Asset Management Plan (TAMP) that identifies investment and management strategies to improve or preserve asset conditions and the performance of the National Highway System (NHS). Although only pavements and bridges on the NHS are required to be included in the TAMP, states are encouraged to include all roadway assets within the right-of-way. At a minimum, the TAMP should include the following information: 1) a summary of NHS pavement and bridge assets, including a description of conditions; 2) asset management objectives and measures; 3) the identification of any performance gap; 4) a life-cycle cost and risk management analysis; and, a 5)10-year financial plan and corresponding investment strategies.
While most states are able to capture past and planned expenditures on capital projects, they are finding it challenging to incorporate maintenance costs into their TAMP. This situation is influenced by a number of factors: 1) maintenance data are not easily linked to pavement and bridge management systems so it is not easy to track maintenance applied to specific pavement sections or bridges; 2) maintenance plans have short-term horizons while longer-term planning documents, such as the Statewide Transportation Improvement Program (STIP), include only capital investments; and 3) maintenance funds are not committed to a single asset type, i.e., agencies generally do not establish a budget specifically for guardrails or culverts.
The absence of maintenance cost data in a TAMP must be addressed to capture the full level of investments being made by states in the transportation system. This requirement is especially important as state transportation agencies shift their focus from system expansion to system preservation, which places more of an emphasis on preventive maintenance activities. The guidance developed under this research will provide the information needed by practitioners to use available pavement and bridge maintenance data to address each of these elements of a TAMP. In addition, the guidance will address the use of available information to incorporate other roadside assets (such as guardrails and culverts) into a TAMP.
The objective of this research is to develop guidance that can be used by state transportation agencies to incorporate maintenance costs more effectively into life-cycle cost analysis, financial plans, and investment strategies included in a TAMP. In support of this objective, the research should include the following steps:
- Review of existing TAMPs and summarize the extent to which maintenance costs are incorporated into the life–cycle cost analysis, financial plan, and investment strategies;
- Identify content are-as where maintenance costs could be better incorporated into a TAMP;
- Determine adequacy of available maintenance data to support the needs in each TAMP content area;
- Develop guidance to better account for past and planned maintenance costs as states develop their TAMP; and
- Prepare a final report that includes the findings, provides guidance for state transportation agencies, and identifies further research needs in this area.
Project 25-61: Effective On-Bridge Treatment of Stormwater
Research Field: Transportation Planning
Source: AASHTO Committee on Environment and Sustainability
NCHRP Staff: Ann M. Hartell
Stormwater treatment of bridge deck runoff has always been a difficult design challenge. Traditional methods of treating bridge deck runoff suggest treating an equivalent area of roadway offsite that discharges to the same receiving water body or piping the bridge deck stormwater to an offsite treatment location. NCHRP Report 778: Bridge Stormwater Runoff Analysis and Treatment Options states, “Treatment of runoff from a comparable section of highway on land is preferable to treatment of runoff from the bridge deck…”. In situations where offsite mitigation is not acceptable due to local regulations surrounding the sensitivity of the receiving water body or site-specific bridge con-ditions (load restrictions or long bridges with very flat grades) that make piping bridge runoff to the bridge ends for offsite compensatory treatment infeasible or undesirable, stormwater designers have very few options for effective on-bridge treatment of stormwater.
There is an urgent need to develop more options for on-bridge treatment of stormwater. NCHRP 778 gives a step-by-step analysis to aid stormwater designers in selecting BMPs for treating bridge runoff. However, the only on-bridge BMP suggested in NCHRP 778 is use of Permeable Friction Course (PFC). NCHRP 767: Measuring and Removing Dissolved Metals from Stormwater in Highly Urbanized Areas says PFC overlays are effective in reducing Total Suspended Solids (TSS) in highway runoff but lack the effectiveness in removing dissolved constituents. Because of this PFCs will not work over rivers, streams, or lakes where there are stringent discharge requirements, or water quality or endangered species concerns. NCHRP Report 767 presents a conceptual on-bridge BMP design that includes an inlet scupper and filtration media to treat metals dis-charged in stormwater runoff.
Compared to collecting and conveying bridge runoff for offsite treatment, on-bridge stormwater treatment has many challenges to overcome which this research proposal would address. Depending on how efficient the on-bridge BMPs are at treating and discharging water through the bridge deck, they could add weight to the bridge design, which could increase the overall cost of the bridge. The on-bridge BMP might also require more spread width for flow to allow runoff to enter the inlet if the media isn’t very efficient at treating and passing stormwater through the drain. Maintenance of on-bridge BMPs may require closing down one lane which might inconvenience the traveling public and increase safety concerns.
An on-bridge BMP must be able to remove the pollutants of concern from bridge deck runoff, have comparable weight requirements to a standard ‘collect and pipe to offsite’ system, be quick and easy to maintain, and have a relatively long life. A significant benefit of an on-bridge BMP would be the ability to allow treated stormwater to drop into the waterbody below without further stormwater pipes or infrastructure. This would work well for a stormwater retrofit of an existing bridge.
The objective of this research is to build on current treatment technologies that utilize media filtration to remove pollutants of concern to develop and evaluate an on-bridge stormwater treatment application. The research will identify media filter materials and different media filter material mixes that effectively remove the major classes of highway runoff pollutants dissolved metals, nutrients and petroleum hydrocarbons (including Polyaromatic Hydrocarbons–PAH) from stormwater. The materials must be usable in the on-bridge BMP configuration(s) by having the appropriate hydraulic characteristics for efficient drainage, sufficient pollutant removal capacity, and minimal maintenance and replacement frequencies. The configurations should be feasible for new bridge and bridge retrofit scenarios without requiring increases in the load bearing capacity of the bridge, and should allow for easy access and maintenance. The research will test potential filter media mixes in two phases: (1) laboratory testing will focus on pollutant removal capability and capacity and hydraulic characteristics and (2) field testing of media types that laboratory testing indicates are well suited for on-bridge BMPs. (The field testing should follow national BMP testing protocols such as the Washington State Department of Ecology’s Testing Approval Protocol Ecology (TAPE) or the New Jersey Corporation for Advanced Technology (NJCAT) to show what types of pollutant removals each BMP design achieves.) The results of the laboratory and field testing will be used to select preferred media mixes and to inform one or more standardized BMP designs. The results of the research will be accompanied by guidance on the selection, design, placement, and maintenance of the identified on-bridge stormwater treatment BMPs, the selection of the appropriate media filter materials and mixes, and the advantages and limitations of the BMPs and media filter materials. The guidance is to be aimed at designers.
Project 08-129: Incorporating Resilience Concepts and Strategies in Transportation Planning Efforts
Research Field: Transportation Planning, Source: AASHTO Committee on Transportation System Security and Resilience
NCHRP Staff: Lawrence D. Goldstein
This problem statement reflects research gaps identified as part of the NCHRP 20-117 project as well as findings from the RISE Summit held in October 2018. Most resilience efforts on the part of state departments of transportation (DOTs) are found in emergency response and to some extent in project design (for example, design exceptions when the context makes a different design appropriate). However, several presentations at the RISE Summit showed the importance of considering resilience efforts in planning efforts in order to set the overall direction of how resilience can be considered throughout the project development process. Corridor studies from Oregon, Colorado and Utah illustrated how corridor-based resilience planning provided direction to potential designs, operations and maintenance. In addition, other state DOTs, such as the Michigan DOT, are examining how resilience concepts could be included in statewide transportation planning. And yet a few others, such as Caltrans, are conducting resilience studies through its planning division. The purpose of this research is to provide more in-depth research on the topic of resilience and transportation planning that can be included in the Resilience Guidebook that is being produced by the NCHRP 20-117 project under way.
As an important contribution to this process, the FHWA has sponsored several efforts that examine the relationship between resilience and transportation planning. These efforts have been at a very high level and not specific enough to include in the Resilience Guidebook. There is a need to provide very detailed and specific advice to state DOTs on how resilience can be integrated into different aspects of transportation planning.
The objective of this project is to develop specific guidance on how resilience concepts can be incorporated into transportation planning efforts at all scales of application. The intent is to integrate the research results into the Resilience Guidebook being developed by the NCHRP 20-117 project. It is expected that the research will look at different types of state DOT planning efforts, such as statewide planning, modal planning and corridor planning, and how resilience could be integrated into such efforts.