Sunday, October 9, 2011

Travel time by Combined Statistical Area

One issue that came up in discussions of my previous post on "cities" (census-defined Metropolitan and Micropolitan Statistical Areas) where the income of the median transit rider is higher than that of the median driver is the fact that many of these MSAs area exurbs of larger cities. In fact, many of the MSAs in the top ten were part of the outer ring of New York City suburbs. I thought it would be interesting to look at Combined Statistical Areas instead: areas that the Census Bureau judges to be part of the same metropolis.

CSA NameDrove Alone Median EarningsPublic Transportation Median EarningsPublic Transportation Earnings Margin of ErrorTransit / Drove earnings ratioTransit - drove / error
Idaho Falls-Blackfoot, ID$25,081$60,962$8,0432.4314.461
Chicago-Naperville-Michigan City, IL-IN-WI$37,166$37,647$1,8241.0130.264
Ponce-Yauco-Coamo, PR$16,026$15,437$5,8640.9630.100
Boston-Worcester-Manchester, MA-RI-NH$41,704$40,073$1,4910.9611.094
Seattle-Tacoma-Olympia, WA$40,914$38,754$3,0920.9470.699
San Jose-San Francisco-Oakland, CA$46,062$41,737$1,2740.9063.395
Washington-Baltimore-Northern Virginia, DC-MD-VA-WV$48,826$42,261$1,6270.8664.035
Youngstown-Warren-East Liverpool, OH-PA$27,387$23,678$10,1530.8650.365
Portland-Lewiston-South Portland, ME$34,105$28,426$12,3400.8330.460
New York-Newark-Bridgeport, NY-NJ-CT-PA$44,837$37,305$3590.83220.981

There's Idaho Falls at the top again, and the Chicago CSA (which combines the Chicago MSA with Kankakee and Michigan City) coming in second. I still haven't figured out what's going on with Ponce. Then come the other big cities: Boston, San Francisco and Washington. New York as a whole (combining Torrington, Kingston, Poughkeepsie, Trenton and Bridgeport with the New York City, Nassau-Suffolk, New Haven, Newark and New Brunswick MSAs) drops to number 10 on the list. Some big US metro areas are missing from the top ten: Philadelphia has dropped to #19 and Houston is at #26. Los Angeles, Dallas and Atlanta are replaced by Seattle, Portland and Youngstown. Yes, in Youngstown, that infamously shrinking city with its nice clockface transit service and a frequency-based map (PDF), transit riders only make a few thousand dollars less than drivers. To be honest, I don't know what's going on there.

CSA NameTotal workforcePublic Transportation commutersCommute Mode ShareMean Drive TimeMean Transit TimeTransit / Drive time ratio
Idaho Falls-Blackfoot, ID76,4401,9232.52%18.2867.973.72
Chicago-Naperville-Michigan City, IL-IN-WI4,382,704480,19510.96%28.5348.611.70
Ponce-Yauco-Coamo, PR116,2081,1651.00%24.3133.421.37
Boston-Worcester-Manchester, MA-RI-NH3,677,685295,1908.03%26.2646.171.76
Seattle-Tacoma-Olympia, WA1,994,521148,2967.44%25.2645.681.81
San Jose-San Francisco-Oakland, CA3,458,438336,7019.74%25.1644.901.78
Washington-Baltimore-Northern Virginia, DC-MD-VA-WV4,375,136489,70511.19%30.6848.331.58
Youngstown-Warren-East Liverpool, OH-PA269,7001,2580.47%#N/A#N/A#N/A
Portland-Lewiston-South Portland, ME309,5972,1680.70%#N/A#N/A#N/A
New York-Newark-Bridgeport, NY-NJ-CT-PA10,076,4782,721,37227.01%27.7450.351.82

In all these cities, the travel time ratio is pretty similar: except for Idaho Falls and Ponce it's between 1.55 and 1.81. Seattle, San Francisco and New York have ferries. Boston and DC, in addition to the above three, have commuter rail. The mode share doesn't seem to affect either the earnings ratio or the time ratio.

The main thing I take away from this list is how close together these CSAs are, with the exception of Idaho Falls, and how low the earnings ratios are. That suggests that in an entire metropolis there are going to be pockets with a high percentage of poor transit riders lorded over by a small elite of drivers, and those will typically balance out the Torringtons and Bremertons of the area. But that doesn't mean that there's no inequality. Here's the bottom ten CSAs:

CSA NameDrove Alone Median EarningsTransit Median EarningsTransit Earnings Margin of ErrorTransit / Drove earnings ratioTransit - drove / error
Detroit-Warren-Flint, MI$36,068$14,263$25620.3958.511
Greensboro--Winston-Salem--High Point, NC$30,399$11,535$34420.3795.481
Syracuse-Auburn, NY$35,282$13,371$84190.3792.603
Lexington-Fayette--Frankfort--Richmond, KY$31,604$11,688$101590.3701.96
Little Rock-North Little Rock-Pine Bluff, AR$32,025$11,263$131570.3521.578
Birmingham-Hoover-Cullman, AL$32,383$11,222$47400.3474.464
Peoria-Canton, IL$35,221$12,168$33780.3456.824
Lafayette-Frankfort, IN$28,684$9249$33450.3225.81
Grand Rapids-Muskegon-Holland, MI$30,796$9634$28620.3137.394
Lansing-East Lansing-Owosso, MI$32,601$7685$33490.2367.44

Here we've got five Midwestern rust belt cities, four mountain Southern cities, and Syracuse. Drivers make three to four times what transit riders make. This is the more typical pattern that everyone expects.

CSA NameWorkforcePublic TransitCommute Mode ShareMean Drive TimeMean Transit TimeTransit / Drive time ratio
Detroit-Warren-Flint, MI2,112,80535,2871.67%25.644.81.75
Greensboro--Winston-Salem--High Point, NC69,310858130.84%#N/A#N/A#N/A
Syracuse-Auburn, NY332,90947201.42%#N/A#N/A#N/A
Lexington-Fayette--Frankfort--Richmond, KY319,22121660.68%#N/A#N/A#N/A
Little Rock-North Little Rock-Pine Bluff, AR392,47721590.55%#N/A#N/A#N/A
Birmingham-Hoover-Cullman, AL513,75026810.52%25.343.91.74
Peoria-Canton, IL182,53411460.63%20.736.21.75
Lafayette-Frankfort, IN108,59130122.77%#N/A#N/A#N/A
Grand Rapids-Muskegon-Holland, MI574,55863401.1%21.435.21.65
Lansing-East Lansing-Owosso, MI237,87048662.05%2230.71.4

None of these cities have rapid transit. Detroit has the People Mover and Little Rock has a heritage streetcar, but those don't actually go from homes to jobs. Syracuse used to have Ontrack, but that was shut down in 2007; ridership had been declining because it didn't go from homes to jobs.

I still can't figure out why there's so much inequality in Detroit, Syracuse, Lafayette and Lansing, but not in Youngstown. Maybe people driving to New Castle to get the bus to Pittsburgh? But in the 2005-2009 ACS, the mean drive time is 22 minutes and the mean transit time is 32 minutes. If anyone has an explanation, please tell me.

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