The 2010 Ford Explorer Sport Trac is the second generation of a vehicle that started a sub-trend: A truck, with sport-utility characteristics, four doors, a rather short cargo bed and an assortment of ingenious features to enhance the anticipated active lifestyles of its intended buyers. It's not quite a sport utility vehicle and it's not quite a truck. On the large size in this group are the Chevrolet Avalanche and Cadillac Escalade EXT, while more directly competitive in size is the Honda Ridgeline. The original Sport Trac was based on the Ford Explorer, as is the newest version. But the Explorer has grown up, both in size and sophistication, and so has the Sport Trac.