I think it's 763mph.
Two people have acctually drove it Ryan sivewright and kieran smith
Thrust SSC (super sonic car) Reached up to 1, 228 KM/H. Follow this link http://www.answerbag.com/q_view/917569
If a car is speeding up, its initial speed is less than its final speed. As the car accelerates, its speed increases over time, so the initial speed is lower than the final speed attained during acceleration.
Nitrox is a gas that can boost your car speed by at about 17%. The highest speed percentage it can take your car to is about 39%.
The highest speed is 115 mph (71.5 metres per second).
The Bugatti Veyron 16.4 SuperSport has the highest top speed. (268mph, 431kph)
A car traveling at a higher speed will have more kinetic energy than a car moving at a slower speed. So, the car with the most kinetic energy would be the one traveling at the highest speed.
The SSC Ultimate Aero has a theoretical highest speed of 462 km/h (287 mph)
The highest speed of an average car is around 190-200 miles per hour. However, some high-performance sports cars can exceed this and reach speeds of 250 miles per hour or more.
62.5 m/s
Im not sure but i think its around 45-50mph =)
Your average car can reach speeds of up to 230km\h. The highest speed reached ever by a car is 413km\h.