It’s way faster than most cars can drive. Even high end performance cars often have a limiter at 250 km/h.
Here in Denmark, the limit is 130 km/h, If you drive 200 or faster, your car is immediately confiscated, and you lose your drivers license.
Many electric cars are limited to 160 km/h.

So in short 300 is about twice what most would consider responsible. The breaking distance is 550 meter or more than half a km, in ideal weather with no slopes, and a response time to push the brakes of only half a second. That’s almost 5 times the breaking distance compared to driving 130 km/h (113 m).
Just in the half second to respond, the car will have moved 42 meters at 300 km/h!!

www.omnicalculator.com/physics/stopping-distance