Increase financial and environmental sustainability by enabling and encouraging walkable housing and retail land use.
Brian Ross, Vice President - Renewable Energy, Great Plains Institute: 612/767-7296, bross@gpisd.net, www.betterenergy.org/who-we-are/staff-and-consultants/
- Market research shows that a majority of future U.S. housing demand lies in smaller homes and lots, townhouses and condominiums in walkable neighborhoods where jobs and activities are close at hand. The Minnesota organization Strong Towns presents evidence for why cities must grow in this manner to remain financially solvent and to cost-effectively increase the stock of affordable housing. Land uses that generate too little property tax to maintain city infrastructure, demographic changes (including shrinking households), periodically high gas prices, lengthening commutes and cultural shifts all point to the need for this smarter (re)development. But rather than some absolute density measure, the fundamental target for any city can be viewed as a target ratio of private investment to public investment somewhere between 20:1 on the risky end and 40:1 on the secure end.
- A 2015 Smart Growth America study shows the 20-year public costs, revenues, and net fiscal impact of four different housing mix strategies in West Des Moines, IA. The more walkable, urban approach to growth would generate an estimated annual net fiscal impact of $11.2 million — $3.7 million more per year than low density development.
- The Center for Neighborhood Technology's Location Affordability Index estimates the percentage of a family's income dedicated to housing, transportation, and the combined cost of both in a given location – city, region, or neighborhood. Transportation costs are largely a function of the characteristics of the neighborhood in which a household chooses to live. Compact and dynamic neighborhoods with walkable streets and high access to jobs, transit, and a wide variety of businesses allow a household to afford more expensive housing because transportation costs can be cut dramatically.
- Driving and the Built Environment: The Effects of Compact Development on Motorized Travel, Energy Use, and CO2 Emissions (National Research Board: 2009).
- Thrive MSP 2040, the current Twin Cities' metro area development vision produced by the Metropolitan Council, sets housing density goals for nine city typologies.
Optional Best Practice for Step 3 Recognition
Category A, B and C cities: implement this best practice by completing any one action.
Accommodating and paying for city growth on the existing city grid and by expanding the grid at nodes with the same or higher population density has multiple and long-term benefits to a city: financial (property taxes/acre), retail commercial, affordable housing, transportation, environmental and social benefits. Returns on such public grey and green infrastructure investments such as streets and boulevard trees are high. These investments help to incrementally raise land values, which combined with the ability of property owners to redevelop their property into something more intense, naturally prompts the redevelopment of property which is otherwise in a state of decline or stasis.
The alternative - large-lot single-family neighborhoods outside the city grid and distant business parks and malls financed and maintained by anticipated future low-density development - cements in long-term, typically higher, costs for provision of city services such as transit, higher personal transportation costs and carbon emissions, and more driving and stormwater generation.
Building lot coverage is set by city codes for different zoning districts, and each city must decide on just how 'building-dense' one or more city districts will be, and how much open space and vegetation (which have benefits such as heat island mitigation) are required.
Changes in the density of selected zoning districts are best paired with changes in four other urban design elements to effect the greatest benefits, such as decreasing vehicle miles traveled. These elements - the "5 Ds" - addressed in other GreenStep best practices and modeled for effectiveness (elasticity) by the Metropolitan Council, are:
- Density
- Design (of streets, buildings, block size; connectivity)
- Diversity (of land uses, including the jobs-housing balance)
- Destination Accessibility (distance from common trip destinations; price of parking)
- Distance-to-Transit
Metric # 7: Land Use