FAQ

What is location efficiency?

Just as buildings can be energy efficient, neighborhoods can be location efficient. Compact neighborhoods with walkable streets, access to jobs and transit, and a wide variety of stores and services have high location efficiency. They require less time, money and greenhouse gas emissions for residents to meet their everyday travel needs.

The savings of location efficiency add up for households and communities. Transportation costs can range from 8% of household income in location-efficient neighborhoods to over 26% in inefficient locations. Greenhouse gas emissions also fluctuate, depending on household reliance on costly, carbon-intensive automobile travel.

How are housing costs derived?

CNT does not derive housing costs. Housing costs come from the American Community Survey and are calculated as the average of Median Selected Monthly Owner Costs and Median Gross Rent scaled by the percentage of owner-occupied housing units with a mortgage, and renter-occupied housing units with cash rent.

How are transportation costs derived?

The unique value of CNT’s H+T® Index is the transportation cost model. Several characteristics of the built environment are used to model transportation costs, including gross density, block density, and percent of single family homes. The model also employs six measures developed by CNT: the Regional Household Intensity (a household gravity measure), Employment Access Index (a measure of job opportunity), Employment Mix Index, Transit Connectivity Index (a measure of transit access), Transit Access Shed (a measure of the area accessible within a 30-minute transit trip), Jobs Accessible in 30 Minute Transit Ride (the number of jobs in the TAS area), and Average Available Transit Trips per Week (frequency of service). For specifics please see the Methodology section.

Are taxes, maintenance and utilities included in the cost of housing?

Housing costs for owners include: mortgage payments, real estate taxes, property insurance, utilities, fuels, mobile home costs and condominium fees. For renters, costs amount to contract rent plus the estimated average monthly cost of utilities and fuels.

How was the 45% affordability benchmark developed? How does it differ from the traditional view of affordability?

Traditionally, a home is deemed affordable if its costs consume no more than 30% of a household’s income. This measure, however, ignores transportation costs—typically a household’s second-largest expenditure—which are largely a function of the area in which a household chooses to locate. Based on research in communities ranging from large cities with extensive transit to small micropolitan areas with extremely limited transit options, CNT has found that 15% of the Area Median Income (AMI) is an attainable goal for transportation affordability. By combining this 15% level with the 30% housing affordability standard, CNT recommends a new view of affordability, one in which combined housing and transportation costs consume no more than 45% of household income.

What is a “regional typical household” and why is affordability reported from this perspective?

The Regional Typical Household assumes a household income that is the median income for the region, the average household size for the region and the average commuters per household for the region. An important aspect of the H+T Index is that transportation costs are modeled for the "typical" household in a region, or the household represented by these three values.

By fixing income, household size and commuters, the model controls for the impact of these variables on transportation costs. Differences in transportation costs are therefore a result of neighborhood characteristics and variation in the built environment. When variables are shown as a percent of income, this median income value is used. Therefore, the variable can be interpreted as the cost impact of a given location on the average household in the region.

CNT modeled data for three households types:

  1. Regional Typical Household, with its assumptions described above.
  2. Regional Moderate Household, which assumes a household income of 80% of the regional median, the regional average household size and the regional average commuters per household.
  3. National Typical Household, which assumes a household income of $53,046 (the national median household income), a national average household size of 2.63 and a national average number of commuters per household of 1.13.

Why the does the Regional Typical Household have fractions of people and commuters?

The Regional Typical Household takes into account all types of households in the region, and does not represent a specific household, but an average of all households. Every region has a unique mix of households: two-commuter households, single-earner households, adults with no children, single people, etc. - so the Regional Typical Household represents a composite of the broad range of households within a region.

Using a typical or representative household, and estimating travel behavior and costs for this representative household, the H+T Index provides a valuable measure of place. By keeping the household metrics constant, the differences in these modeled costs represent changes in behavior that are induced by the place and its environment, and not by the various households living in each neighborhood.

How is walkability measured?

Measures of street connectivity have been found to be good proxies for pedestrian friendliness and walkability. Greater connectivity between streets creates smaller blocks and tends to lead to more frequent walking trips. The model uses average block density as a proxy measure for walkability.

How are regions defined?

The regions used in the H+T Index correspond to the Core Based Statistical Areas (CBSA) defined by the Office of Management and Budget (OMB) for use by federal statistical agencies in collecting, tabulating, and publishing national statistics. The term Core Based Statistical Area (CBSA) is a collective term for both metropolitan and micropolitan areas.

Does the H+T Index account for qualitative characteristics of a neighborhood such as quality of schools or crime rates?

The H+T Index model does not include characteristics such as crime and school quality that might factor into a household’s location decision. The Index’s contribution is to focus on the interplay between the two largest portions of most household budgets: housing and transportation costs.

Is the cost of parking considered in the model?

The model does not currently incorporate the cost of parking and other miscellaneous transportation expenses, including tolls and taxis.

Why are auto costs different than previous versions of the H+T Index?

Previous versions of the H+T Index used auto ownership costs from AAA’s Your Driving Costs, which is one of the most widely used measures of costs for owning and operating a vehicle. It is employed by government agencies, industry experts and transportation consultants and is based on amortized purchase costs for the first five years of a newly purchased auto and includes per mile costs for maintenance, repairs and fuel. This version of Index uses costs derived from the Consumer Expenditure Survey (CES) in order to derive a more representative measure of costs for autos up to 10 years old. These costs are a product of research commissioned by the Department of Transportation (DOT) and the Department of Housing and Urban Development (HUD).

How are greenhouse gas emissions calculated?

To calculate greenhouse gas emissions, vehicle miles traveled (VMT) is modeled for the local household. The local household differs from the regional typical household in that income, household size and commuters per household are not fixed and reflect the average for households living in each block group. These figures come directly from the American Community Survey. A standard emissions factor of 0.438 metric tonnes of CO2 per mile is then applied to the local VMT estimates to get the emissions figure.

How can I compare two different maps?

The H+T Index website has several map comparisons (Location Affordability, Greenhouse Gas Emissions) in addition to the H+T Index single-map view where all the available variables can be mapped. Options to view other map comparisons include: opening a second tab with another H+T Index single-map view, printing out the maps of interest, or downloading the block group level data and creating your own maps.

Is the H+T Index data available for download?

Yes, the model outputs and built environment variables are available for free download on the Data page. Transit and greenhouse gas variables, as well as longitudinal and custom datasets, are available for purchase. If you are interested in data beyond what is available here, please contact Linda Young (linda@cnt.org).

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