Using Transportation Conformity as a land use planning tool

The Clean Air Act as Amended (1990) requires that all Metropolitan Planning Organizations (MPO) in maintenance areas for criteria air pollutants such as carbon monoxide (CO) must have conforming transportation plans. This means that all MPO plans must have at their core a fiscally-constrained set of transportation plans which will conform to the Environmental Protection Agency (EPA) accepted State Implementation Plan (SIP) for air quality maintenance. Fiscal constraint requires that reasonable programmed expenditures back such plans. Unplanned suburban fringe development often tends to accelerate the timing for the extension of arterial roadway infrastructure. Unless exogenous financing is found, monies shifted to accommodate any untimely roadway extension must be deleted from other programs or projects in the transportation plan because of fiscal constraint mandates. If unplanned roadway mileage, and vehicle miles traveled (VMT) are added to the system, socioeconomic assumptions for the Transportation Conformity analysis may be altered. These unplanned shifts in demographics and additional transportation infrastructure can have adverse impacts on emissions limitations underlying periodic air quality maintenance (Conformity) demonstrations required by the EPA. In air quality maintenance areas without growth management plans, these conforming transportation and air quality plans, along with the local capital improvements plan can serve as a powerful land use planning tool. Transportation Conformity, originally conceived to link transportation to air quality, may be used as a valid justification for achieving orderly development based upon planned infrastructure extension and opposing premature fringe development projects and suburban sprawl.