Table 3,,,
Comparison of NHTS Trip Estimates to Other Travel Data,,,
,Monthly average pre-9/11 period (Mar. 2001-Sept. 11 2001),"Monthly average post-9/11 period (Sept. 12, 2001 - May 2002)",Percent change
Vehicle Miles Traveled,,,
     Actual,242.3,225.1,-7.1
     Forecast in absence of 9/11,242.3,225,-7.2
NHTS Personal Vehicle Trips (millions.) ,,,
     Estimated,201.8,181.2,-10.2
Air RPM (millions.),,,
     Actual,63.1,46.4,-26.4
     Forecast in absence of 9/11,63.1,58.1,-7.8
NHTS Air Trips (millions),,,
     Estimated,18,14.1,-21.7
Rail RPM (millions.), ,,
     Actual,508.3,439.1,-13.6
     Forecast in absence of  9/11,508.3,436.4,-14.1
NHTS Train Trips (millions.),,,
     Estimated,1.7,1.6,-5.5
NHTS Bus Trips (millions.),,,
     Estimated,5.1,4.5,-12.1
"SOURCE: U.S. Department of Transportation, Research and Innovative Technology Administration, Bureau of Transportation Statistics.",,,
"NOTE:  Shaded difference not significant at a 0.05 level.    Pre- and Post-9/11 monthly estimates of VMT are prorated for the NHTS survey overlap months of March, April, and May 2001 and 2002, using NHTS pre-and post-9/11 datasets.  The weights for the overlap months are calculated using the proportion of trips taken in those months from the pre-and post-9/11 datasets.  September 2001 is prorated using 0.33 for the pre-9/11 weight, and 0.67 for the post-9/11 weight",,,