[tristor]

I agree with your instructor. That said, modern cars can stop in /much/ shorter distances than previously, largely thanks to improvements in tire technology.

Nearly every production vehicle available today can brake from 60mph in less than 140ft, more performance oriented vehicles can do so in under 120ft. The standards for “safe stopping distance” used in the US triple this distance to account for slowed reaction time because drivers are not attentive.

Realistically less than doubling these figures is correct for attentive drivers. 60mph is 88 feet per second, and 1 second is plenty of reaction time for an attentive driver, meaning 200-240ft total stopping distance, closer to double the distance the vehicle is capable of rather than triple.

So if the visibility is less than 200-240ft, you should be going slower than 60mph. 240ft isn’t very far in a car though, it’s roughly the distance traveled in 3 seconds at 60mph. There’s certainly some country roads I’d slow down on, but if you’re paying attention you’re well good on most.

For what it’s worth, the average reaction time of a gamer is 150ms, so a full second is plenty of margin of error.

[midasuni]

U.K. stoping distance is 240ft at 60mph, 120ft at 40mph. 75ft at 30.

[phalf]

> the average reaction time of a gamer is 150ms

It's rare that those gamers have a crying toddler in the backseat while being sleep deprived and the sun coming from a less than perfect angle.

[InSteady]

Also not generally being surrounded on all sides by other unpredictable gamers whose own split-second reactions are going to determine what their safest move should be.