Originally Posted by
stedalus
If you can look at that graph and think that you know the grade down to 0.1%, more power to you. (Pun not intended. I'll quit here.)
Yeah, maybe 0.1% is a tad optimistic -- but there's something wrong with your dv/dt. I'm guessing you were just using a simple difference? Real roads don't change slopes as drastically as you're estimating.