Any business newspaper will tell you that the economy is doing well, and that both trucking and railroads are charging a hefty premium to move goods these days. A quick look at Old Dominion Freight Line's (NASDAQ: ODFL) earnings results tells you how tight the trucking market really is. Even after expanding capacity, the company was able to extract much higher prices from customers; it posted one of the most efficient quarters in its history.Here's a look at how the quarter broke down, and at what investors can expect from Old Dominion in the future.DATA SOURCE: OLD DOMINION FREIGHT LINE EARNINGS RELEASE.