Automakers are getting closer to something they've wanted to do for years: eliminating the spare tire, according to USA Today. Relying on so-called run-flat tires to make spares obsolete would free space for more people or cargo, cut weight for better acceleration, handling and fuel economy, and cut automakers' costs. But it might be unsafe, USA Today said. "The spare is still part of the rear crush system on many cars," said General Motors North American chief Bob Lutz. "The spare is definitely part of the rear energy absorption system," confirmed Volvo spokesman Dan Johnston. Run-flat tires go 90 miles or so without air and are gaining acceptance. Not yet mainstream, run-flat tires nevertheless could be on 100,000 new vehicles in 2003, USA Today estimates.