These are the plans that I found for CableOne (dated October 2007):

http://www.cableone.net/internet/limits.htm

It appears that once you reach your volume cap, they halve your connection speed.

I haven't seen that approach over here, just daily and monthly volume limits. The providers are generally not too aggressive about it, but if you persistently exceed the terms of you plan they will shift you to a more expensive one.

Our providers seem to have a different business model............... peak time would be considered to be something like 08.00 to 18.00Hrs, which is what they consider to be peak for the telephone system as well. I guess that they are trying to give priority to business customers?