FIGURE 1-9 Ecological hierarchy indicated by the spatial and temporal scales of vegetation structures (needles, patches, and forests), disturbance processes (fire), and atmospheric structures (fronts).

cerns to be balanced with goals of transportation mobility, capacity, and other social needs in determining whether and how to undertake transportation projects. This can create controversy between supporters of a project and opposers who raise issues of ecological protection. These are primarily federal level acts that either directly or indirectly influence activities at smaller spatial scales.

Chapter 6 addresses the current practices of planning and assessing road projects. Large-scale planning processes (such as long-range transportation plan) are required to address only air quality issues (such as attainment of standards) and generally do not address other environmental issues. Integration of environmental concerns into transportation planning should be done earlier in the planning processes. Such organizations as the metropolitan planning organizations should conduct first-level screenings for environmental considerations in transportation improvements before the development of a transportation improvement