U.S. sales of full-size pickup trucks have slowed in recent months on rising interest rates and high gas prices, increasing pressure on Detroit's automakers to boost incentives and clear swollen inventories.

In the first six months of the year, U.S. sales of four of the best-selling nameplates in the mid-sized SUV segment -- the Ford Explorer, Chevrolet TrailBlazer, Jeep Grand Cherokee and Dodge Durango -- are down 20 to 30 percent.

The pickup truck segment has been a source of profitability for the Big Three automakers, which have steadily lost market share in other categories to Asian brands in recent years.

General Motors has responded by canceling plans to redesign the TrailBlazer in 2009. Instead, GM will roll out more crossover vehicles. The automaker has recognized that the mid-sized SUV segment is showing no signs of recovery.

Overall, automakers had a total of 1.02 million pickup trucks sitting on U.S. dealer lots at the end of June, up 11 percent from a year ago.

The high current inventories suggest that we will see strong sales of pickup trucks in August and September.