In early October, Koenigsegg shattered the 0-400-0 km/h world record set by the Bugatti Chiron just weeks earlier, with a 1,360-hp (1,014-kW) Agera RS destined for a customer in the US. The French auto manufacturer's successor to the Veyron, the Chiron, has yet to complete a top speed run.
The test was carried out on an 11-mile stretch of road between Las Vegas and Pahrhump, that had been closed to the public.
The Agera RS used in the attempt is the same one that recently set a time of 37.28 seconds for the 0-250-0 miles per hour run.
Swedish high-performance auto manufacturer Koenigsegg has broken the top speed record for a production vehicle.
It broke the previous record of 267.9 miles per hour set by Bugatti's Veyron Super Sport in 2010. On Saturday, factory driver Niklas Lilja reached 277.9 miles per hour (447.1km/h) in one of the company's Agera RS hypercars.
Koenigsegg also claims to have set another record on the day.
According to Jim Lau from Racelogic - the folks who helped verify the speed with various VBox data loggers - the event was actually put on by Koenigsegg owners. American tuner, Hennesey, claimed it built the world's fastest vehicle with its 968kW, Lotus-based Venom GT after it questioned whether the Veyron's long-standing record was illegitimate as the auto was driven without its electronic speed limiter, and therefore not representative of its road-going specification. With Lilja behind the wheel, the Agera RS managed to go from 0 to 401.78 kph (249.65 mph) and back to 0 in just 33.87 seconds.
Special mention should be made regarding the tires the Agera RS was running. Responsible for sending the power to the pavement was reportedly a set of Michelin Pilot Sport Cup2 tires - the standard tire for the Agera - which seemed to survive the high-speed stint without a hitch.