The TOP 1 Ack Attack is a specially constructed land-speed record streamliner motorcycle that, as of March 2013, has held the record for world's fastest motorcycle since recording a two-way average speed of 605.697 km/h (376.363 mph) on September 25, 2010, in the Cook Motorsports Top Speed Shootout at Bonneville Speedway, Utah. The Ack Attack's fastest one-way speed was officially recorded at 634.217 km/h (394.084 mph). This was the third time in four years the Ack Attack had broken the motorcycle land-speed record.