[3niner]

Funny, I use my speedometer to estimate my speed.

The length of a white line is of no relevance to a driver, so there is no reason they should know it. All that matters is whether a white line is solid or broken.

Any driver who is paying enough attention to the white line, to accurately estimate its length, is focussed on the wrong thing, and more likely to have an accident.

[Daffynition]

Good advice.