Many years ago, we completed a project called Access to Destinations. The data from the project has been sitting on my hard drive for many years. I am happy that some of it is now preserved for posterity and open science by the University of Minnesota Data Conservancy. See:
Unfortunately, due to small methodological changes, these data are not directly comparable with more recent outputs, and the 1995 – 2005 data are really not directly comparable with the 2010 data either. It nevertheless might be interesting for selected applications.
Travel Time Platform is a website that lets users draw Isochrones, areas which can be reached in a given amount of time (Iso from the Greek for same, chronos for time). I have used it to draw a time radius. Here we show a 30 minute walking time from the Seymour Centre (near the WalkSydney world headquarters, but you can choose anywhere.)
The 30 minute city is a concept about accessibility, can the important places travelers want to go be reached in a given time. The idea that 70% of the people can reach daily activities within 30 minutes of walk, bike, or transit is embedded in the most recent Metropolis of Three Cities plan of the Greater Sydney Commission.
This study estimates the accessibility to jobs by auto for each of the 11 million U.S. census blocks and analyzes these data in the 50 largest (by population) metropolitan areas.
Travel times are calculated using a detailed road network and speed data that reflect typical conditions for an 8 a.m. Wednesday morning departure. Additionally, the accessibility results for 8 a.m. are compared with accessibility results for 4 a.m. to estimate the impact of road and highway congestion on job accessibility.
Rankings are determined by a weighted average of accessibility, with a higher weight given to closer, easier-to-access jobs. Jobs reachable within 10 minutes are weighted most heavily, and jobs are given decreasing weights as travel time increases up to 60 minutes.
The report presents detailed accessibility and congestion impact values for each metropolitan area as well as block-level maps that illustrate the spatial patterns of accessibility within each area. It also includes a census tract-level map that shows accessibility patterns at a national scale.
Accessibility is the ease of reaching valued destinations. It can be measured for various transportation modes, to different types of destinations, and at different times of day. There are a variety of ways to define accessibility, but the number of destinations reachable within a given travel time is the most comprehensible and transparent, as well as the most directly comparable across cities.
This report examines accessibility to jobs by transit in 46 of the 50 largest (by population) metropolitan areas in the United States. Transit is used for an estimated 5 percent of commuting trips in the United States, making it the second most widely used commute mode after driving. This report complements Access Across America: Auto 2013, a report of job accessibility by auto in 51 metropolitan areas. …
Rankings are determined by a weighted average of accessibility, giving a higher weight to closer jobs. Jobs reachable within ten minutes are weighted most heavily, and jobs are given decreasing weight as travel time increases up to 60 minutes.
This report describes the data and methodology used in the separate publication, Access Across America: Transit 2014. That report examines accessibility to jobs by transit in 46 of the 50 largest (by population) metropolitan areas in the United States. Transit is used for an estimated 5 percent of commuting trips in the United States, making it the second most widely used commute mode after driving. Rankings are determined by a weighted average of accessibility, giving a higher weight to closer jobs. Jobs reachable within ten minutes are weighted most heavily, and jobs are given decreasing weight as travel time increases up to 60 minutes.
The research was sponsored by the Center for Transportation Studies at the University of Minnesota. Accessibility Observatory reports, including the analysis of job accessibility by auto published last year Access Across America: Auto 2013, and interactive maps are available for download at: access.umn.edu/research/america.
Visit the site to see the reports, rankings, data, and maps.
This study describes the development and application of a set of accessibility measures for the Twin Cities region that measure accessibility by the automobile mode over the period from 1995 to 2005. In contrast to previous attempts to measure accessibility this study uses travel time estimates derived, to the extent possible, from actual observations of network performance by time of day. A set of cumulative opportunity measures are computed with transportation analysis zones (TAZs) as the unit of analysis for the years 1995, 2000 and 2005. Analysis of the changes in accessibility by location over the period of study reveals that, for the majority of locations in the region, accessibility increased between 1995 and 2005, though the increases were not uniform. A “flattening” or convergence of levels of accessibility across locations was observed over time, with faster-growing suburban locations gaining the most in terms of employment accessibility. An effort to decompose the causes of changes in accessibility into components related to transportation network structure and land use (opportunity location) reveal that both causes make a contribution to increasing accessibility, though the effects of changes to the transportation network tend to be more location-specific. Overall, the results of the study demonstrate the feasibility and relevance of using accessibility as a key performance measure to describe the regional transportation system.
Other reports in the series can also be downloaded here