How much do you trust an indicator?

[morqthana]

Assuming you can keep up with the vehicles ahead, I find there is an ideal range of space to maintain, between you and the vehicle ahead.

Two seconds in the dry, possibly twice that in the wet.

If you're good at estimating distances that's 1 yard and 2 yards for every mph.

 

[Harry Bloomfield]

Two seconds in the dry, possibly twice that in the wet.

I find, that even a wet road, can be less slippy, than even a dry road at times. A dry road, which hasn't seen rain for a while, dusty, greasy, perhaps diesel, can be much worse than a wet road, after a good wash from rain has cleaned the road surface.

 

[morqthana]

What you want is a dusty, greasy, road, with a light coating of diesel, just after a short shower.