Trying to keep pace with high-end competitors, General Motors' Buick brand will increase its bumper-to-bumper warranty coverage to four years or 50,000 miles on all 2006 models, up from three years or 36,000 miles, the Detroit Free Press (DFP) reported.

The paper said Buick also will make the OnStar in-vehicle communications system standard on all models beginning in 2006.

The new warranty will cover virtually everything except oil changes, Buick Division general manager Steve Shannon told the DFP.

It also includes roadside assistance and courtesy transport when vehicles have to remain in the dealership overnight, he said.