The U.S. Bureau of Transportation Statistics’ Transportation Services Index (TSI) rose 0.4 percent in April, the latest month available, to 111.7. The TSI April 2012 level of 111.7 was 2.3 percent higher than the April 2011 level. The index, which is seasonally adjusted, combines available data on freight traffic, as well as passenger travel, that have been weighted to yield a monthly measure of transportation services output.