Having just returned from a 3000+ mile drive myself, I feel able to
comment on driving through curves. One breaks at the beginning of a curve
if one feels that one is going too fast for the curve. (One should reduce
one's speed to the correct value BEFORE entering the curve.) One
accelerates near the end of the curve because one realizes that one has
slowed down too much. (It is much better to have slowed too much at
the beginning of a curve than to discover too late that one has not slowed
enough.)
Usually curves have a constant radius. Sometimes, especially on (poorly
constructed) freeway exits or entrances the radius shortens as one
progrsses through the curve. In such instances one often sees tire
marks on the curb or other tracks indicating that cars left the road.