Late on July 26 (Washington time), The Fifth Estate corrected the attribution by Professor Peter Newman of Curtain University to the effect that driving was down 43% and transit up 65% in the United States. This issue had been the subject of my column on the same morning. It was a simple decimal error (in the reporting) and has now been corrected on the site. Driving is now reported as being down 4.3% and transit up 6.5%. Professor Newman provided slides with the data to Ms. Tina Perinotti, who forwarded them to me.
While the new figures are less inconsistent with the official figures than the former, there are still material inconsistencies.
Driving Trend: Official Data: The slides provided simply refer to the two figures as relating to the past year, without a source or specific period. The 4.3% driving decline is more than double the largest annual decline reported by the official source for such information, the Federal Highway Administration (Figure 1).
Transit Trend: Official Data: We reviewed the data published from the official sources for transit data (the American Public Transportation Association and the Federal Transit Administration) and found no recent annual data indicating a 6.5% increase in ridership (either in boardings or in passenger miles). Much of the transit ridership gain from 2007 to the peak year of 2008 was lost in 2009, according to data posted by APTA in early March (Figure 2). A later first quarter report by APTA indicates further losses. Moreover, as we indicated in our article, the percentage decline in transit use since the peak year of 2008 is many times that of the decline in driving.
Not All Percentages Are the Same: Care must also be used in comparing percentage changes between transit and driving, because so little travel is on transit. For example, a one percent increase in roadway urban travel converts to about one-third of a mile per person per day. A one percent increase in transit use converts to about 30 feet per person per day, about the same distance as walking from one side to the other of the average bedroom and back.
Note: It is possible that the 4.3% driving decline was taken from an interim Federal Highway Administration report indicating that driving declined 4.3% in March 2008 compared to March 2007 (a monthly comparison, not a year on year comparison). This FHWA report, however, is subject to annual revision based upon the more comprehensive Highway Performance Monitoring System, which in 2009 revised the March 2008 such that the annual change became 2.7%.
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