And speaking of commute times, Harry Kao writes in to tell me he has created a Google Maps visualization based on the bit in my book about the historical constancy (in some cases) of commute times. You can find it here (click on the map to engage).
And here are the details, which Kao notes need refining (and I wonder how this differs from WalkScore’s new “Commute” tab). Perhaps someone out there can help?
The primary data source is the CTPP 2000. This survey was sent to a subset of households during the 2000 Census and records, among other things, where people live and work.
The CTPP has since been superseded by the ACS. Although transit statistics from the ACS have been published more recently, the the new data is not sufficiently fine-grained for use with this map.
The CTPP provides data on a census tract level. However, this map uses zip codes to identify regions because they’re more familiar to most people. The mapping from census tract to zip code is done by using the Census Zip Code Tabulation Areas (ZCTAs) to determine the proportion of each census tract that falls within each zip code and weighting the CTPP data accordingly.
The Google Maps API is used to determine routes and transit times. The usual caveats apply. In particular, it is assumed that all commuters drive during non-peak hours. This is surely incorrect (but it’s the best that I can do) so the trip times are likely to be underestimates.
This entry was posted on Monday, September 13th, 2010 at 10:13 am and is filed under Commuting. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.