Assuming 60km/hr for city and 110km/hr for highway, I managed to come up with the following figures, 300m at 60km/hr is 18 seconds, and 600m at 110km/hr is about 19.6s, although this could be rounded up to 20 seconds.
I assume giving the driver time to respond was the point to profiles, I notice in the doc a difference in angles from the current heading but this could easily be solved in a similar manner too.
My question is do profiles really need to exist for this purpose at all?
A alternative solution would be to multiply the current speed in metres/second out by 20 seconds and have that be the warning distance.
Or did I over look something fundemental again?