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Environmental Research: A Decade of Accomplishments 1990 - 2000

ERP Significant Accomplishments in the 1990s

While numerous research products were developed under the ERP during the 1990s, this section highlights a representative set of accomplishments in each of the three broad focus areas: Natural Environment, Human Environment, and Integrated Decisionmaking. These accomplishments illustrate the types of research undertaken through the ERP- analytical, technical, policy, and planning. Much of the environmental research conducted during the 1990s was in the form of guidance and tools for use by State DOTs and MPOs in making transportation decisions. Over the years, however, new transportation legislation and environmental standards have affected the research perspectives and needs of States and local communities. As those needs and requirements changed, we refocused our research goals, products, and support to reflect and meet them. The FHWA will continue its environmental research responsiveness by developing and improving prediction models, conducting natural resource analyses, and promoting sound environmental practices.

A complete listing of research projects completed during the 1990s or underway is included as the Appendix to this report.

Natural Environment

Global Climate Change Literature Review

This comprehensive literature review of issues related to transportation and global climate change is intended to assist policymakers in initiating the discussion over transportation's role in the global climate change debate during the post-Kyoto era. This review is particularly timely because of the increased attention to global climate change over the past few years, the agreements reached in Kyoto, and the substantial role of transportation in the creation of greenhouse gases (C02).

Transportation Conformity Reference Guide

This product provides a comprehensive reference tool on all elements of the transportation conformity process and is designed for transportation agency planners, policy makers, and technical staffs. The guide is organized so that it is easy to look up information on a specific topic or to find more comprehensive information on procedural issues related to the conformity process (e.g., interagency consultation, project level analysis, etc.). Over 40 exhibits are provided to visually portray various elements of the conformity process, and extensive references are provided in each chapter and in the bibliography. The FHWA intends to keep this guide updated so that it may serve as a resource for States and MPOs that are required to comply with the transportation conformity requirements as they evolve.

Evaluation of the MOBILE Vehicle Emission Model

Under the Clean Air Act Amendments of 1990, the EPA requires that States (except California) and MPOs use the MOBILE model for forecasting motor vehicle emissions. Pursuant to the transportation conformity process, the analysis that results from use of the MOBILE model along with regional travel demand forecasts is the basis on which transportation conformity is determined. Since the model has changed over time, this paper was important to users in the mid-1990s because it illustrated the differences between MOBILE 4 and 5 and offered important pointers to modelers in States and MPOs. The EPA is currently working on releasing MOBILE 6, which, once released, will become the required emissions model for all states except California. When MOBILE 6 is released, the FHWA will provide technical assistance to States and MPOs on the use of the model for mobile source emissions forecasting.

VMT Growth and Improved Air Quality: How Long Can Progress Continue?

This booklet explains the relationship between growth in vehicle miles traveled (VMT) and air quality. By showing past trends in air quality improvement nationwide and future emissions reduction trends, it is useful to State DOTs and MPOs in transportation investment decisionmaking.

Atmospheric levels of all four pollutants to which motor vehicles contribute significantly- airborne lead, carbon monoxide, nitrogen dioxide, and ozone- have declined consistently for almost 2 decades. In addition, violations of the National Ambient Air Quality Standards for airborne lead, carbon monoxide, and nitrogen dioxide have been virtually eliminated. Controlling ground-level ozone (or "smog" ) has proven more challenging, but violations of the Federal ozone standard have decreased.

Most of the reductions in atmospheric concentrations of these pollutants can be attributed to lower emissions by motor vehicles. Since 1970, tighter emissions standards for cars and trucks have significantly reduced vehicular emissions of carbon monoxide and volatile organic compounds (VOC, a primary ingredient of ozone).

This analysis examines whether reductions in motor vehicles' VOC and oxides of Nitrogen (NOx) emissions rates- which are likely to result from recently adopted control strategies- could be offset by continuing growth in vehicle miles traveled during the foreseeable future. It also investigates how rapidly motor vehicle emissions of various pollutants might resume growing if their long-term decline is reversed, and compares the potential future increase in emissions to their historical decline. Finally, the analysis explores how this potential increase in motor vehicle emissions might be postponed by further tightening of new car emissions standards or other proposed emissions control strategies that have not yet been adopted.

In summary, the analysis shows that emission control measures already in effect are likely to extend the decline in motor vehicles' VOC emissions for at least another decade, and further tightening of new car emissions standards could prolong this decline by approximately another 10 years. In the case of NOx, tighter standards for new vehicles (trucks and automobiles) are likely to be necessary to achieve the same result, although significant emissions reductions from off-road vehicles and equipment should also be possible.

Transportation and Air Quality Public Education Campaign

This FHWA initiative, in partnership with the Federal Transit Administration and the EPA, is a multiyear effort to support national environmental and transportation objectives through a campaign to increase awareness of the link between travel behavior, traffic congestion, and air quality. The goals of the public education campaign are to improve citizens' quality of life, health, and the environment through education; increase the awareness of alternative travel modes and the importance of travel choices; and encourage positive behavioral change to reduce transportation-related emissions. The public education campaign, which is conducted at national and local levels, includes advertising as well as pilot tests, with participants representing a broad coalition of interests. The key benefits expected from this initiative are enhanced national and local government partnerships; leveraged resources from a variety of sources; and establishment of a national, sustained effort to reduce emissions and traffic congestion through lifestyle choices and related changes in travel behavior.

Wetland Mitigation Database

The FHWA has recently published a wetlands mitigation accounting database entitled, System for Wetlands Accounting and Management Program, for recording and analyzing wetland mitigation efforts. The program will greatly facilitate wetland mitigation recordkeeping and reporting of wetland loss/gain data. The database, developed through our environmental research program and completed during fiscal year 1998, will provide the State DOTs with a tool for managing their wetland mitigation activities associated with highway improvements.

The database directly supports the FHWA Administrator's fiscal year 1998 and 1999 performance agreements, which call for a 50 percent increase in net wetland area resulting from Federal-aid highway projects by 2008. We have been monitoring performance each year by conducting a national survey of the States for their wetland loss/gain data. The new database will enable the State DOTs to monitor their mitigation performance during the year and easily report the annual results to the FHWA.

Wetlands and Highways: A Natural Approach

This brochure discusses alternative approaches to minimizing wetland loss as well as wetland mitigation projects and mitigation banking to protect wetlands, and highlights 10 wetland mitigation projects that have received acclaim for their innovation and success. The brochure also discusses tips for potential mitigation bankers and provides information on existing and planned wetland mitigation banks throughout the United States.

Evaluation and Management of Highway Runoff Water Quality (Water Quality Synthesis)

This manual consolidates the results of past research on highway runoff and water resources. The single volume manual is useful to highway designers and environmental professionals by presenting the available and appropriate impact prediction and mitigation tools for use during highway project planning and development activities. This manual is a self-contained desk reference for highway practitioners and includes an extensive bibliography.

Ultra-Urban Best Management Practice Assessment and Analysis of Highway Stormwater Runoff (original title); Stormwater Best Management Practices in an Ultra-Urban Setting: Selection and Monitoring.

A compilation of available literature on ultra-urban best management practices (BMPs) resulted in this searchable database on runoff pollution reduction methods suited to limited space application. Included with the database are BMP selection criteria and decision support system, as well as appropriate monitoring design and implementation recommendations.

FHWA Highway Traffic Noise Prediction Model

The new FHWA Traffic Noise Model (TNM) was released on March 30, 1998. This marked the end of more than 6 years of research to develop a new model to incorporate over 2 decades of improvements in the state of the art of predicting highway traffic noise, as well as continuing advancements in computer technology. The TNM bases its calculations on totally new acoustical prediction algorithms, as well as newly measured vehicle emission levels for automobiles, medium trucks, heavy-duty trucks, buses, and motorcycles. Early validation of the TNM has shown an improvement in prediction accuracy.

This technical assistance tool is directly useful to State and local planners and analysts who are continually struggling to address the noise impacts of transportation projects, particularly in rapidly growing urban and suburban areas served by major highways. The TNM aids in providing a better understanding of noise issues associated with the design of new or reconstructed transportation facilities. This understanding helps the FHWA encourage State and local governments to regulate land development in such a way that noise-sensitive land uses are either prohibited from being located adjacent to a highway, or that the developments are planned, designed, and constructed in such a way that noise impacts are minimized.

Handy look-up tables are available to provide highway traffic noise analysts with a screening tool to be used in simple applications of the TNM (i.e., straight, uncomplicated roadway and/or barrier geometries with level terrain).

Human Environment

Community Impact Assessment

The Community Impact Assessment brochure was written as a quick primer for transportation professionals and analysts who assess the impacts of proposed transportation actions on communities. It outlines the community impact assessment process, highlights critical areas that must be examined, identifies basic tools and information sources, and stimulates thought on individual projects. The primer is intended to increase awareness of the effects of transportation actions on the human environment and emphasizes that community impacts deserve serious attention in project planning and development. In addition, the guide provides useful suggestions on facilitating public involvement in the decisionmaking process.

Flexibility in Highway Design

This guide is about designing highways that incorporate community values and are safe, efficient, effective mechanisms for the movement of people and goods. It is written for highway engineers and project managers who want to learn more about the flexibility available to them when designing roads. In ISTEA, and again in TEA-21, the Congress stressed preserving historic and scenic values and provided dramatic new flexibilities in funding for facilities with historic or scenic significance. In addition, in TEA-21, the Congress promotes more bicycle and pedestrian-friendly transportation facilities and encourages consideration of bicycle lanes and sidewalks in new or updated transportation plans. The guide does not establish any new or different laws, or geometric design standards or criteria for highways and streets, but provides a wealth of information on how highways can be designed to achieve enhanced mobility and help achieve other community objectives.

Integrated Transportation and Environmental Decisionmaking

Public Involvement Techniques in Transportation Decisionmaking

This document incorporates all of Innovations in Public Involvement for Transportation Planning (which is no longer available). It was prepared to introduce agencies to a variety of practical techniques in public involvement that can be used in different situations. It is geared to the needs of State agencies and MPOs, particularly smaller MPOs with less extensive public involvement experience. It is intended for use both by public involvement specialists and others who have such responsibilities. While the document discusses a number of public involvement approaches, techniques should always be tailored to local conditions and be as creative and fresh as possible to attract public interest.

This publication was designed to be user-friendly and succinctly explains techniques such as charrettes, visioning, brainstorming sessions, citizens advisory committees, and a variety of media strategies. It is a starting point to stimulate responsiveness to ISTEA (and now TEA-21), where new emphasis on public involvement has become a key feature of transportation planning in States and metropolitan areas

Considering Cumulative Impacts Under the NEPA

This handbook offers a fresh look at the impacts of projects by taking a more holistic approach (i.e., cumulative impacts) than in the past. The question of how to consider cumulative impacts has received much attention in recent years, and this publication is a tool for evaluating how Federal actions can interact with actions by other governmental and non-governmental entities to affect important environmental resources in a cumulative way.

The handbook presents the results of research and consultation by the Council on Environmental Quality (CEQ) concerning the consideration of cumulative effects in analyses prepared under the National Environmental Policy Act of 1969 (NEPA). It introduces this complex issue, outlines general principles and useful steps, and provides information on methods of analysis and data sources. It does not establish new requirements for analyses and is not considered CEQ guidance nor is it legally binding. More specifically, Considering Cumulative Impacts Under the NEPA provides a framework for advancing environmental impact analysis by addressing cumulative effects in either an environmental assessment or an environmental impact statement. It presents practical methods for addressing coincident effects (adverse or beneficial) on specific resources, ecosystems, and human communities of all related activities, not just the proposed project or alternatives that initiate the assessment process.

FHWA Guidebook on NEPA Project Development Process

This compilation of regulations, guidance, memoranda, and other communications in a CD format enables FHWA field offices and State and local transportation professionals to access a wealth of information on the FHWA/NEPA project development process. The FHWA selected the CD format for the guidebook to simplify the stakeholders' access to updated information in a timely manner. In addition, the guidebook is available on the Internet at

Technology Transfer Achievements

The FHWA has been aggressive in using Technology Transfer to help get information to its field offices and stakeholder groups in a timely manner and to provide expanded training opportunities for FHWA, State, and local agency staffs. Through the use of media such as teleconferences, meetings, workshops, and publications, the FHWA has greatly expanded the scope of its outreach to stakeholders. For example, during the past several years, the FHWA has participated in 17 teleconferences sponsored by the Center for Transportation and the Environment (CTE) at North Carolina State University. The National Teleconference Series of CTE is the only national broadcast event dedicated to surface transportation and the environment. Examples of teleconferences in which FHWA participated include: Wildlife Ecology and Transportation; Examining the Planning and Environmental Provisions of ISTEA; the Integration of Watershed Management and Transportation Planning; Transportation Implications of EPA's New/Revised Standards for Ozone and Particulate Matter; Wetlands Mitigation for Transportation Projects; Update on the CMAQ Program and Transportation Control Measures; Implementing the Environmental Streamlining Provisions of TEA-21; and Best Practices in Wetland Mitigation and Stream Restoration. These teleconferences have been very well received and proved to be a viable and successful way to share policy and program information among transportation and environmental practitioners.

In addition, the FHWA has participated in numerous workshops and conferences, since ISTEA was enacted in 1991, to help engage practitioners in the identification of issues and environmental research needs. New training materials have been developed and, through the National Highway Institute, courses are designed to teach and inform implementing agencies and FHWA field staff of environmental issues that need to be addressed in planning and project development processes.

Numerous publications have also been developed by the FHWA to communicate needed information, best practices, innovative techniques, and other technical assistance to transportation professionals. The products of the ERP have been well received and recognized by State and MPO staffs as valuable tools to use in the planning and project development processes.

Awards and Special Recognition

Environmental Excellence Awards

In 1995, the FHWA launched this biennial awards program to officially honor partners, projects, and processes that excel in protecting and enhancing the environment while at the same time meet a growing transportation demand. Every 2 years, these awards recognize winning entries from individuals and groups that have broken new ground, created new partnerships, increased public involvement, and enhanced environmental and archaeological sensitivity. The competition for these awards is intense, with fewer than 20 recipients selected every 2 years from dozens of applicants throughout the country. The FHWA is encouraged by the excellence of the candidate projects and looks forward to continuing this important program to reward achievement in the pursuit of environmental excellence.


This report has provided an overview of the Environmental Research Program and examples of completed research efforts that address the human environment, the natural environment, and integrated decisionmaking. We encourage readers to take a look at the Appendix to this report, which contains a full listing of research projects that were completed during the 1990s or are ongoing. As we enter the 21st century, the FHWA will continue to promote, encourage, and conduct environmental research that helps State and local implementing agencies plan for and fund environmentally sound transportation projects. By working closely with our stakeholders, we are encouraged that the progress made in the 1990s can, and will, continue into the next decade.

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Updated: 10/13/2011
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