Landon Sproull, Peterbilt Motor Co.'s chief engineer, said the company invested over $100 million in product improvements in 2007 alone and plans to continue that effort this year in a number of areas. For starters, he pointed to a new proprietary front air leaf suspension option for its Class 8 tractors that improves ride performance by 20%, is compatible with air disc brakes, and improves tire life.

Sproull said that later this summer Peterbilt plans to offer a new dash for its medium-duty trucks, complete with a new navigation system to make those vehicles more productive for fleets.

The OEM is also giving hybrid technology a lot of attention in three distinct areas, he said: a hydraulic hybrid designed to offer either performance or fuel economy benefits to refuse-truck operators; Class 6 and 7 medium-duty diesel-electric hybrids; and testing of its second-generation Class 8 OTR diesel-electric hybrid in conjunction with Wal-Mart's fleet.

According to Sproull, using available tax credits combined with fuel and other operating savings over the life of these hybrids can balance out the nearly 30 to 40% higher sticker price when compared to diesel-only models.

Finally, Peterbilt is working with Wal-Mart to test four Model 386 tractors powered by LNG in Napa Valley, CA, this year.