1. Bugatti Chiron Super Sport 300+: In August 2019, a modified version of the Bugatti Chiron, called the Chiron Super Sport 300+, achieved a speed of 304.773 mph (490.484 km/h) at the Ehra-Lessien test track in Germany. This record-breaking achievement was officially certified by the Guinness World Records as the "Highest Speed Attained by a Production Car."
2. Koenigsegg Agera RS: In November 2017, a prototype of the Koenigsegg Agera RS, driven by company test driver Niklas Lilja, set a new world record for the "Fastest Production Car" with an average speed of 277.9 mph (447.2 km/h) over two runs in opposite directions on a closed public road in Nevada, USA. While this speed is below 300 mph, the Agera RS has been estimated to be capable of higher speeds, with some experts suggesting it could potentially reach over 300 mph under ideal conditions.
It's important to note that both of these supercars were driven on closed tracks or test environments under strictly controlled conditions and with safety precautions in place. Attempting to reach such extreme speeds on public roads would be incredibly dangerous and illegal.
