All phases of road developmentâ€"from construction and use by vehicles to maintenanceâ€"affect physical and chemical soil conditions, water flow, and air and water quality, as well as plants and animals. Roads and traffic can alter wildlife habitat, cause vehicle-related mortality, impede animal migration, and disperse nonnative pest species of plants and animals. Integrating environmental considerations into all phases of transportation is an important, evolving process. The increasing awareness of environmental issues has made road development more complex and controversial. Over the past two decades, the Federal Highway Administration and state transportation agencies have increasingly recognized the importance of the effects of transportation on the natural environment. This report provides guidance on ways to reconcile the different goals of road development and environmental conservation. It identifies the ecological effects of roads that can be evaluated in the planning, design, construction, and maintenance of roads and offers several recommendations to help better understand and manage ecological impacts of paved roads.
The tool kit will vary among jurisdictions depending on basic legal constraints, community attitudes, road system and traffic characteristics, and resources. The Transportation Research Board (TRB) undertook a study to identify the sources of safety improvements in other countries. Researchers do not have a complete understanding of the underlying causes of long-term trends in crashes and fatalities. Differences among countries are in part attributable to factors other than government safety policies. To identify keys to success, the TRB study committee examined specific safety programs for which quantitative evaluations are available and relied on the observations of safety professionals with international experience. The committee's conclusions identify differences between U.S. and international practices that can account for some differences in outcomes. The committee recommendations, which are addressed to elected officials and to government safety administrators, identify actions needed in the United States to emulate the successes that other countries have achieved. The recommendations do not comprehensively address all aspects of traffic safety programs but rather address areas of practice that are highlighted by the international comparisons and for which credible evidence of effectiveness is available."--Pub. desc.