To quote from www.formula1.com
BAR hit 415 km/h in CaliforniaBAR have unofficially broken the 400 km/h barrier during their preparations for a Formula One land-speed record attempt, now scheduled for Bonneville early next year.
After rains at the famous Salt Flats in Utah washed out the team's plans to set a new standard in 2005, a final shakedown was organised at the Mojave airbase in California.
During this test, South African Alan van der Merwe, bettered the 400 km/h mark no fewer three times, with a best of 415 km/h, almost 258 mph. The car was a specially, prepared, but still race legal, version of this year