You may have heard of the three-second rule, which is intended to prevent tailgating. Essentially, it just means that you should always be at least three seconds behind the next car. This way, if that car stops suddenly, you have enough time to react and stop without hitting it.
It's easy to figure out. Just pick a fixed point on the side of the road -- like a sign -- and then count off seconds after that car passes the point. If it takes your car three seconds to pass it, you're far enough back.
But is this always a good enough rule?
It's not. If the weather is bad, you need to drop back a bit farther, and experts recommend simply doubling your space. This means staying six seconds back in snow, fog, rain or darkness. You may also want to adjust it when traffic gets heavier than normal.
If the conditions really get bad, then you may want to triple it and stay nine seconds back. You can do this in heavy fog or rain, for instance, or when it's snowing so hard that the road is covered in it and you can hardly see where you're going. That extra space makes up for slower reaction times and longer stopping distances.
Test out this rule the next time you're on the road. What you'll find is that most people do not give you nearly enough space. They're just a second or two back if you're lucky. When these dangerous drivers cause accidents, you may need to seek out financial compensation for medical bills and other costs.