I wonder if reaction time is a factor. Driving in congested traffic, I've noticed that it's difficult or even impossible to maintain what we were all taught was

I wonder if reaction time is a factor. Driving in congested traffic, I've noticed that it's difficult or even impossible to maintain what we were all taught was a safe following distance. As a result, the drivers are not in complete control of their cars. For instance if someone stops suddenly in front of them, they crash.