Copyright © National Academy of Sciences. All rights reserved.
This executive summary plus thousands more available at http://www.nap.edu
Assessing and Managing the Ecological Impacts of Paved Roads
http://books.nap.edu/catalog/11535.html
xxvi
Contents
2-5 Example of rectangular grid pattern of roads in Chicago, 50
2-6 Example of hub-and-spoke pattern of roads found in
Washington, DC, 51
2-7 Traffic congestion map showing a concentration of congested
highways in the southeastern and south-central regions of New
Hampshire, 57
2-8 Percentage of vehicle miles traveled on urban freeways and
principal arterials occurring under congested conditions from
1987 to 2000, 58
2-9 Pavement surface condition of the national and interstate
highway systems, 58
3-1 Road affecting four aspects of stream connectivity, 72
3-2 Sources of 23 pollutant constituents in storm-water runoff, 74
3-3 Schematic representation of the primary ecological effects of
roads on species and populations, 78
3-4 Wildlife crossings are designed to link critical habitats and
provide safe movement of animals across busy roads, 81
3-5 Spatial and temporal dimensions of ecological effects of roads,
90
4-1 Illustration of a reduction in total road length reducing the
ecological effect of roads and traffic, 101
4-2 Illustration of the effect of traffic volume on the roadavoidance zone or the distance maintained by those animals
that avoid a road, 102
4-3 Illustration of reducing traffic near ecologically sensitive water
bodies, 103
4-4 Conceptual illustration of the general relationship between the
width of the road-effect zone and the volume of traffic on the
road, 104
4-5 Illustration of how the ecological effects of a new road can be
mitigated by consideration of surrounding land use, 105
4-6 Illustration of mitigation measures to reduce the ecological
effects of roads when it is not possible to redirect traffic away
from natural areas, 106
4-7 Examples of ecological restoration performed by ongoing road
maintenance operations, 115
6-1 EPA ecological framework: essential ecological attributes, 189
6-2 The spectrum of environmental performance measures, 189
This executive summary plus thousands more available at http://www.nap.edu
Assessing and Managing the Ecological Impacts of Paved Roads
http://books.nap.edu/catalog/11535.html
xxvi
Contents
2-5 Example of rectangular grid pattern of roads in Chicago, 50
2-6 Example of hub-and-spoke pattern of roads found in
Washington, DC, 51
2-7 Traffic congestion map showing a concentration of congested
highways in the southeastern and south-central regions of New
Hampshire, 57
2-8 Percentage of vehicle miles traveled on urban freeways and
principal arterials occurring under congested conditions from
1987 to 2000, 58
2-9 Pavement surface condition of the national and interstate
highway systems, 58
3-1 Road affecting four aspects of stream connectivity, 72
3-2 Sources of 23 pollutant constituents in storm-water runoff, 74
3-3 Schematic representation of the primary ecological effects of
roads on species and populations, 78
3-4 Wildlife crossings are designed to link critical habitats and
provide safe movement of animals across busy roads, 81
3-5 Spatial and temporal dimensions of ecological effects of roads,
90
4-1 Illustration of a reduction in total road length reducing the
ecological effect of roads and traffic, 101
4-2 Illustration of the effect of traffic volume on the roadavoidance zone or the distance maintained by those animals
that avoid a road, 102
4-3 Illustration of reducing traffic near ecologically sensitive water
bodies, 103
4-4 Conceptual illustration of the general relationship between the
width of the road-effect zone and the volume of traffic on the
road, 104
4-5 Illustration of how the ecological effects of a new road can be
mitigated by consideration of surrounding land use, 105
4-6 Illustration of mitigation measures to reduce the ecological
effects of roads when it is not possible to redirect traffic away
from natural areas, 106
4-7 Examples of ecological restoration performed by ongoing road
maintenance operations, 115
6-1 EPA ecological framework: essential ecological attributes, 189
6-2 The spectrum of environmental performance measures, 189