Private fleets don't haul freight for profit, but instead quietly distribute products, deliver services, keep supply chains moving, and perform other essential services for their parent businesses. Even though they operate over 6.6 million of the 8.1 million commercial trucks running on U.S. roads, private fleets are also the invisible side of the trucking industry, functioning as indispensable tools to help businesses succeed in their primary missions rather than as profit-making businesses in their own right.

The FLEET OWNER 500, a ranking of America's top private fleets, was created to recognize the size and scope of those often under-appreciated operations. Like first two reports, the 2006 FLEET OWNER 500 bases its rankings on total power units controlled by a fleet. We also provide a breakdown by tractors and straight trucks for each fleet, as well as information on trailers in the fleet and the parent company's business category.

For the third year in a row, total equipment numbers for the Top 500 fleets grew, this time by more than 3% over 2005. All of that growth was in the straight truck category, with both tractors and trailers remaining essentially the same. Reflecting that growth, the smallest private fleet in the 2006 Top 500 had 211 power units, compared to 153 last year.

Fleets at the top of the 2006 list remained relatively stable, with some minor shifts up or down in the rankings. However there was much more movement in the middle and bottom of the list, which accounted for most of the 98 new companies on this year's list.

Transportation Technical Services (TTS) collected the data for this report using a number of public and proprietary sources including its owner Fleet Seek ( online search tool and FLEET OWNER's subscription records. TTS then verified the data by contacting the fleets directly. The National Private Truck Council also assisted by urging members to help us update the collected information.