TRAMM - Transit Mobility Map

TRAMM (TRAnsit Mobility Map), is a web-based framework for visualizing a synthesis of General Transit Feed Specification (GTFS) data and census data to expose areas of ``transportation poverty,'' defined as areas where social disadvantage and poor transit quality coincide. The framework provides the ability to import, analyze and view data as raster layers that overlay Google Maps or OpenStreetMap, making it possible to examine the data in a neighborhood context.

The TRAMM navigation form (on the upper right side of the map page) provides the following controls:

City: Select the name of a city to view
Demographic: Select the name of a census demographic layer to display. Demographic layer data comes from the 2000 U.S. Census (Summary File 3) and can include the following census tract data:

% Persons in Poverty: The percent of population below the Federal poverty level (P87. Poverty Status in 1999 by Age). In New York City, this is percent of households with an income under $30,000 per year
Median Household Income: From "P53. Median Household Income in 1999 (Dollars)"
% Over 60 Minute Commute: From "P31. Travel Time to Work for Workers 16+ Years"

Transit: Select the name of a transit information layer to display. Transit layers are created by analyzing GTFS data. Different layers can include:

Service Frequency: Number of vehicles per hour at each stop. Varies by time of day.
Service Capacity: Rough estimate of the number of vehicle seats per hour at each stop. Varies by time of day.
Route Frequency: Number of vehicles per hour.
Route Capacity: Rough estimate of the number of seats per hour.
Transportation Poverty: The level of poverty (% of households) offset by quality transit service.
Public Transportation Accessibility Level (PTAL): A measurement of public transit availability used in London. Indexes range from 0 (poor) to 40 (excellent). The indexes are categorized into levels from 0 (poor) to 6 (excellent). PTAL is also combined with census tract poverty to give a PTAL Poverty level, indicating areas where poor transit quality and high levels of poverty coincide.
Local Index of Transit Availability (LITA): An index initially used in Florida in 1997 that measures intensity of transit service. Scores range from 0 (poor) to 10 (excellent).
Travel Time: Travel time in minutes to various reference points in each city. Varies by time of day.

Time: For transit layers that have values that vary by time of day, this provides the ability to move through different times in the day.
Base Map: The street map that always sits underneath the demographic and transit layers. Choices include various forms of Google Maps and OpenStreetMap.
Opacity: The level of transparency of demographic or transit layers.
Help: This help text
KML: A link to a KML version of the currently visible map that can be viewed in Google Earth.

Rev. 16 July 2010