The redesigned Cadillac CTS, Chevrolet Camaro, and Pontiac G8 are safe. The car most affected by this decision is the redesigned Chevrolet Impala and other planned variants. Bob Lutz says the future of GM's rear-wheel-drive projects is on hold while the automaker deals with fuel-efficiency and emissions concerns. NEW YORK CITY — For now, the upcoming Chevrolet Camaro sport coupe has apparently dodged a bullet. But General Motors vice chairman Bob Lutz told the Chicago Tribune on Tuesday that the automaker has "pushed the pause button" on future rear-wheel-drive vehicles. "It's no longer full speed ahead," Lutz said. He added that "it's too late to stop Camaro, but anything after that is questionable or on the bubble." Also safe is the Pontiac G8, Jim Hopson, manager of Pontiac Communications, told Inside Line. "There's no hold on the G8," said Hopson. "G8 production starts in October and the first units will be available after the first of the year." Still on the bubble are future Camaro derivatives, including a big Impala sedan. Trouble is that rear-wheel-drive cars are bigger, heavier and thirstier than front-wheel-drive vehicles. Lutz notes that the corporation has yet to figure out "how to get 30 percent better mileage from" RWD cars. The Bush administration is pushing to boost CAFE standards by 4 percent a year so cars would have to average 34 mpg by 2017, up from 27.5 mpg today. In addition, the U.S. Supreme Court ruled last week that the EPA can regulate carbon dioxide expelled by cars. At the same time, Alan Weverstad, executive director of GM's environment and energy units, told a federal judge on Tuesday that vehicle carbon emissions reductions ordered by California and 10 other states would require average fuel economy standards for cars and the lightest category of trucks of 43.7 mpg. Lowering the carbon emissions as much as the states want will involve "fuel economy requirements that are just unbelievably extreme," Weverstad said, according to the Associated Press. Automakers involved in the federal trial are trying to hinder states from adopting new standards aimed at lowering emissions of carbon dioxide. ------ General Motors' product guru Bob Lutz has said the company's rear-wheel-drive program is on hold, but it's not yet clear whether this will mean good or bad news for Holden exports. By IAN PORTER. Holden may have to dramatically increase and extend its US export program after parent company General Motors put all its US rear-wheel-drive programs on hold in the face of proposed stiffer fuel economy standards. At first glance, the new standards will make it harder for GM to produce rear-wheel-drive cars in the US, especially the profitable high-performance V8 models. However, GM will have the option of building the cars outside the US because the corporate average fuel economy (CAFE) standards apply to imported cars and domestically built cars separately. GM imports most of its small cars and makes the majority of its larger cars in the US and Canada. The Bush administration has proposed that fuel economy standards be raised gradually from 27.5 miles a gallon (10.3 litres per 100km) to 34mpg by 2017 as part of a plan to cut oil consumption and reduce emissions. In addition, the US Supreme Court this week ruled that the Environmental Protection Agency - and not the administration - has the right to regulate vehicle emissions of carbon dioxide. There are no carbon dioxide emissions in the US limits at present. GM vice-chairman Bob Lutz said the company had halted all its US rear-wheel-drive car programs while it seeks clarification of the new regulations. "We've pushed the pause button (on rear-wheel-drive programs)," Mr Lutz told the Chicago Tribune on Monday. "It's no longer full speed ahead." "We don't know how to get 30 per cent better mileage from rear-wheel-drive cars." Holden is the world centre for GM's large rear wheel drive programs and developed the Zeta rear-wheel-drive platform for its new VE Commodore. GM was planning to put that platform into production in the US and other countries. It has just started producing the WM long-wheelbase version in China, where it will be sold as the Buick Park Avenue, with Australian V6 engines, and is about to start making the Camaro two-door sports coupe and convertible in Canada. GMH has been developing the Camaro at its Australian proving ground. "It's too late to stop the Camaro, but anything after that is questionable, or on the bubble,'' Mr Lutz said. "We'll decide on our rear-drive cars when the Government decides on C02 (carbon dioxide) levels and CAFE regulations,'' Mr Lutz said. Should GM decide not to make RWD cars in the US, it will have to make them somewhere else, but a GMH spokesman was uncertain about the consequences of the stiffer fuel economy rules. "As it's not our policy to speculate on future production or portfolio issues, we're not in a position to offer any elaboration on what implications _ positive or negative _ such a suggestion might have," GMH spokesman John Lindsay said yesterday. GMH is set to start exporting a V8 version of the Commodore to the US as a Pontiac G8 later this year. The parent company was planning to start making the G8 in the US, but the stiffer fuel economy regulations may prompt GM to keep sourcing its G8s from GMH after the two-year contract expires. Mr Lutz said the three 1 litre compact cars GM displayed at the recent New York Motor Show would not help the company meet the stricter economy rules. "Small car mileage only counts towards CAFE if you build them here, and you can't build small cars here at a profit,'' Mr Lutz said in Chicago.