• Increase allowable densities in places with public infrastructure.  Public policy should prohibit land use regulations that mandate artificially low residential and commercial densities in infill locations with public transportation and water and sewer infrastructure.  When we enforce short height limits next to our train stations, when we require excessive parking for office buildings in urbanized areas, or when we mandate land application sewer systems when public sewer is readily available, we squander past infrastructure investments, erode housing affordability, and push development further out and farther apart.  (See the 2008 book Rethinking Federal Housing Policy by economists Edward L. Glaeser and Joseph Gyourko (AEI Press) which argues persuasively that local land regulation is a chief contributor to local-market housing unaffordability.)  
• Make walkable urbanism "by right."  Sadly, walkable neighborhoods are often outlawed by local zoning regulations; walkable neighborhoods are rarely a "by right" use.  Every traditional neighborhood development (TND) Arcadia has proposed has required an amendment to the zoning ordinance to mix uses, to shrink lot sizes, and to tighten road geometry.  Worse yet, many older walkable infill communities (which shall remain nameless here) would be impossible to build under extant zoning.  We recently contributed to proposed legislation being drafted by State Rep. Bob Freeman in Pennsylvania that will go a long way towards increase the adoption of traditional neighborhood development as a by-right use.
• Treat urban and suburban places differently.  Obviously, a traditional main street is different than a commercial arterial.  A block of rowhouses is different from a large-lot estate development.  Transportation and environmental regulation often fails to discern the difference, applying one-size fits all policies to vastly different conditions.  Because the regulators themselves encounter more low-density development than dense development, suburban norms are often applied to infill areas, generating excessive costs and eroding traditional urban design qualities.
• Increase the cost/lower the subsidies of sprawl.  One way to increase the viability of infill development is to increase the cost of sprawl or to reduce its subsidies.  The true cost of low-density sprawl is not contained within the real estate transaction between builder and buyer; sprawl generates externalities in the form of traffic, tax, and environmental impacts which are passed on to society in general.  Regulation, impact fees and tax policy could redirect these costs back to the homebuyer--where it belongs.

These policies would go a long way towards redirecting development to infill locations.  Unfortunately, the reality of fragmented local government in much of the United States makes implementation of these policies nearly impossible.  Because the negative impacts of development are generally contained within municipalities while the benefits are more diffuse, opposition to development has become a constant refrain in local politics.    To make these smart growth policies happen, we need Federal or state level action that would create powerful incentives for local government to enact smart growth policies.  As recommended by Glaeser and Gyourko (2008): "The federal government should lean against the local tendency to restrict new construction."