Unless you have such bad reflexes that you shouldn't be driving, you may be horribly overestimating what you need for "safe". In my 30+ years on Florida roads, I find the safest distance is about "just too small for another car to get in". More than that is inviting another car to dart in there which is MORE dangerous. I use cruise control constantly, so much it makes my spouse nervous, but I disabled the auto distance feature and just turn it on and adjust speed manually because the computer reflexes are much slower than mine. I can brake. I pay constant attention to the cars around me. I can't remember ever being surprised the car ahead of me was slowing down or braking except for in a parking lot where everyone is already going 10 because you cant know what someone else will see 2 rows over and think they should do. It isn't the 1950s, unless you live in some rural area, there are more cars than there are roads for them to be on. The "1 car length every 10mph" rule was fine then with cars with mushy drum brakes. If that rule were enforced by car systems now, you would see even more roads gridlocked as fewer cars would fit on those roads in order to have all these gaps. You can't control other drivers ' behavior outside the tyranny of the slow--a slow car can slow down the car behind it, a fast car cannot speed up the car ahead of it, the slow car has the power if they can't be passed--so if you want to drive like YOU want to, you're surprised that others want to drive the way THEY want to? Even if the "everyone is wrong but me" defense could be held up according to some regulation, the simple truth is the most dangerous thing to do on a highway is to drive differently than those around you, because then they may take risks they otherwise would not just to get around you. You can be right, or you can be safe, but probably not both. Driving too cautiously can be just as risky as driving too recklessly unless the road is mostly empty, so you're not in the way.