Indicators for
Sustainable Mobility

A tool for cities to effectively develop sustainable transportation policies.

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In the United States, transportation accounts for nearly 30 percent of all greenhouse gas emissions. As cities attempt to become more sustainable, it is imperative that they curb those emissions.

The Indicators

ITDP has defined indicators that are actionable, scalable, and easily understood. There are many existing indicators of sustainable transit, but many of them are developed using indices that become black boxes, leaving little discernible actions to improve them.

Many other existing indicators suffer from an over reliance on complexity, thus requiring a high level of technical knowledge to fully understand and act upon them.

In order to avoid those pitfalls, the indicators presented here are easily understood, replicable, and can be tied to policy interventions. We hope this data can be used to advocate for improvements.

  1. Access to Transit
    • People Near Rapid Transit

      People Near Rapid Transit (PNT) is an indicator that measures the percentage of the population that is within a 10 minute walk or bike ride of a rapid transit station. This indicator, along with the other proximity indicators, is measured using walking and also includes biking on protected bike lanes. Rapid transit is defined as any Bus Rapid Transit (BRT) corridor, LRT corridor, or rail-based transit mode that meets the BRT basics definition in the BRT Standard.

    • Jobs Near Rapid Transit

      Jobs Near Rapid Transit is a measure of the percentage of jobs that are within a roughly 10-minute bike ride or walk of a rapid transit station. Rapid transit is defined as any Bus Rapid Transit (BRT) corridor, LRT corridor, or rail-based transit mode that meets the BRT basics definition in the BRT Standard.

    • Low Income Households Near Rapid Transit

      Low-income Households Near Rapid Transit measures the percentage of the population that makes less than $20,000 a year that lives within about a 10-minute bike ride or walk of a rapid transit station. This was selected because it is just below the federal poverty level for a family of three ($20,780). Rapid transit is defined as any Bus Rapid Transit (BRT) corridor, LRT corridor, or rail-based transit mode that meets the BRT basics definition in the BRT Standard.

    • People Near Frequent Transit

      People near frequent transit (PNFT) measures the percentage of the population within a roughly 10-minute bike ride or walk of a frequent transit stop. Stops are defined as frequent if they are served an average of five times an hour (around a 12-minute headway) from 7 a.m. to 9 p.m. on a weekday, and include rapid transit stations.

    • Jobs Near Frequent Transit

      Jobs Near Frequent Transit is a measure of the percentage of all jobs that are within a roughly 10-minute bike ride or walk of a frequent transit stop. This indicator uses the same parameters as People Near Frequent Transit―an average of five departures per hour from 7 a.m. to 9 p.m.

    • Low Income Households Near Rapid Transit

      Low-income Households Near Frequent Transit is a measure of the percentage of households that are making less than $20,000 that live within a roughly 10-minute bike ride or walk of frequent transit. This indicator uses the same parameters as People Near Frequent Transit―an average of five departures per hour from 7 a.m. to 9 p.m.

  2. Accessibility
    • Access to Jobs by Sustainable Transit (60 & 30 Minutes)

      Access to Jobs by Sustainable Transit measures the average of the number of jobs that can be reached within 30 minutes and 60 minutes for each census tract within the area by walking, cycling (on protected bike lanes), and public transit. This indicator is a percentage of all of the jobs in the city.

    • Access to Low Skill Jobs by Sustainable Transit (60 & 30 Minutes)

      This indicator is a measure of the average of the number of jobs that require less than a high school education that can be reached by walking, cycling, and public transport within 30 and 60 minutes for each census tract in the area.

    • Access to People by Sustainable Transit (60 Minutes)

      This indicator is a measure of the average of the number of people that can be reached within 60 minutes for each census tract in the area. This indicator was developed as a proxy measure for access to jobs in areas where job data was not available.

  3. City Characteristics
    • Block Density

      Block Density is a measure of the average number of city blocks per square kilometer of study area. Blocks are defined as developed areas that are surrounded on all sides by publicly accessible pedestrian passages.

    • Weighted Population Density

      This indicator represents the average experienced density of a person in the city. Unlike a traditional population density, which measures the amount of people in an area, this measure is weighted by the population of each census tract, which provides a more nuanced understanding of population density.

Key Results

From this 25-city analysis, we found some interesting results:

  • People Near Frequent Transit and Access to Jobs are the indicators that most strongly predict Sustainable Transport Mode Share.
  • Cities with the highest shares of People Near Frequent Transit had strong corridors of frequent transit coverage as opposed to disparate islands of coverage.
  • While many cities have large percentages of jobs located near frequent transit, only those that also have large shares of their population near frequent transit show high Sustainable Transport Mode Shares.
  • When measuring accessibility to jobs, our analysis shows that the total number of jobs that can be reached is more important than the percentage of jobs in terms of influencing Sustainable Transport Mode Share. In other words, when travelers are making decisions about how they choose to get to work, it is more important that they can reach a large number of jobs than a large share of jobs.
  • When measuring accessibility to destinations, we found that the 30-minute threshold correlates with Sustainable Transport Mode Share more strongly than the 60-minute threshold, indicating that it may be a more useful threshold for measurement.
  • While lower-income residents tend to have greater access to public transit than the overall population, their ability to reach jobs that require less than a high school education is lower than the average job accessibility for the whole population.
  • Access to People was established as a reliable proxy measure for Access to Jobs in the United States.

Methodology

By making transparent and actionable indicators, analysis can be easily communicated not just to people working within the public transportation sphere, but also to city politicians and community advocates.

The indicators developed as a part of this research endeavor were calculated primarily using ArcGIS. Further, the majority of them were calculated using the ArcGIS network analyst extension. All of the data used in this process was free of cost.

The road data was collected from OpenStreetMaps, the GTFS data was collected from TransitFeeds and from various transit agencies. United States population and income data was from the United States Census American Community Survey 2015 3 year estimates. US job data was from the Longitudinal Employer Household Dynamics 2015 survey, also from the United States Census.

Canadian population data was from the Canadian census, and Mexico population data was from the Mexican Census. In addition to the open source data used, city boundaries were used to define the extent of the city.

For more information on the methodology, please download the full report.