General Motors Corp. will produce a full-size pickup truck featuring a hybrid powertrain beginning in 2004, underscoring GM's intent to remain the nation's fuel-economy leader.

GM's light truck fuel efficiency today is 4 percent better than Ford's.

"It's simple: We lead in truck fuel economy today and General Motors intends to remain the leader in five years," Vice Chairman Harry J. Pearce told reporters at a briefing Wednesday.

Pearce also announced that GM and its Allison Transmission Division will begin delivery this year of a "hybrid" powertrain for transit buses.

"Buses might be the single most important step to reduce transportation emissions for the U.S. or any other country," Pearce said. "There are about 13,000 transit buses in service in the nine largest U.S. cities. If we could replace those buses with ones featuring the GM hybrid system, this country would use nearly 40 million fewer gallons of diesel fuel every year. To put that in context, that is the equivalent fuel savings of 584,000 small cars with hybrid propulsion systems."

The two hybrid powertrains unveiled by GM will meet or exceed the power performance of a conventional powertrain. GM full-size hybrid pickup trucks, versions of the popular Chevrolet Silverado and GMC Sierra, will deliver top performance with near 15 percent better fuel economy.

Later this year, GM will begin testing its hybrid pickups in demonstration fleets in several U.S. cities. The demonstration will help GM engineers understand what hybrid vehicle features and performance features are important to pickup truck customers.

The hybrid bus powertrain was designed and developed by GM Allison Transmission Division based in Indianapolis. The GM Allison system will offer 50 percent better fuel economy compared with a conventional diesel-engine transit bus. The system also will cut nitrous oxide emissions by 30 percent, while cutting particulate, hydrocarbon and carbon monoxide emissions by 90 percent, when fueled with low-sulfur fuel.

GM Allison works with transit bus manufacturers who then sell the buses to public and private transit systems. GM Allison is also developing hybrid systems for other commercial vehicles.

"As a manufacturer of motor vehicles, we have a special responsibility," Pearce said. "GM has the global reach, innovative capability and market motivation to develop the technologies that will allow us to minimize our impact on the environment and meet customer demands."

"Hybrid propulsion is just one of the technologies that we can introduce to meet the performance expectations of our customers, yet protect this planet that we all count on to sustain us," Pearce said.

General Motors (NYSE: GM), the world's largest vehicle manufacturer, designs, builds and markets cars and trucks worldwide.

GM is investing aggressively in high technology and e-business within its global automotive operations and through such initiatives as e-GM, GM BuyPower, OnStar and its Hughes Electronics Corp. (NYSE: GMH) subsidiary.