To meet the regulatory requirements of the Clean Air Act Amendments of 1990, metropolitan planning organizations, state officials, legislators, and courts with oversight responsibilities are currently being asked to make judgments about the likely effects of highway capacity additions on air quality on the basis of their interpretation of the best available information. The Executive Committee of the Transportation Research Board initiated an 18-month study, the results of which are summarized in TRB Special Report 245, "Expanding Metropolitan Highways--Implications for Air Quality and Energy Use", to evaluate the scientific evidence about the impacts of highway capacity additions on traffic flow characteristics, travel demand, land use, vehicle emissions, air quality, and energy use in metropolitan areas. The TRB study does not resolve the broader debate--which involves value judgments about the relative importance of mobility, economic growth, environmental protection, and energy conservation--but it does review the state of knowledge and the reliability of forecasting tools available to planning agencies to predict the effects of expanding highway capacity on air quality and energy use. This article comments on the findings of the TRB study and presents the study's concluding observations.


  • English

Media Info

  • Pagination: 3 p.
  • Serial:
    • TR News
    • Issue Number: 183
    • Publisher: Transportation Research Board
    • ISSN: 0738-6826
  • Publication flags:

    Open Access (libre)

Subject/Index Terms

Filing Info

  • Accession Number: 00722647
  • Record Type: Publication
  • Report/Paper Numbers: HS-042 177
  • Files: TRIS, TRB
  • Created Date: Jun 26 1996 12:00AM