General Motors on Tuesday said it would take steps to avoid rollovers in its 15-passenger vans, six months after US safety investigators recommended that Detroit vehicle makers improve the vehicles, Reuters reported. GM said it will install vehicle stability enhancement systems, which use sensors to detect wheel skid and apply brakes to maintain control, as standard equipment in the GMC Savana and Chevrolet Express vans during the 2004 model year, which begins this summer, Reuters said.