How do you exit the freeway?

I have a commute to work of about 28 miles each way.  A portion of that is on Interstate 39 in Wisconsin. 

As I merge on to the freeway each morning, there is inevitably a back up in the right lane due to cars slowing down to get off the freeway at the next exit.  This makes it somewhat unsafe as not only am I merging, but I'm also trying to get into the left lane to get around all these yahoos who have the nerve to be getting off at the next exit.  (That's a joke--mostly  :))

This led me to call to remembrance in my learning to drive days the seriousness with which both my dad and brother admonished me to not slow down until you are ON the off ramp or in the exit lane.  If you slow down in the lane of traffic prior to the ramp, you could/would be run over or cause an accident.

However, that was back when the speed limit was 55 mph on the interstate.  The speeds are faster now, have the on and off ramp criteria changed to allow for the increased speeds of the vehicles using the entrance and exit lanes?  Do you have to slow down prior to the exit lane in order to have your vehicle stopped at the end of the exit ramp?

After doing some research and reading a few articles which I will link for your reference, the answer in a lot of cases is yes--in order to safely stop your vehicle at the bottom of the exit ramp, you must begin slowing down prior to the exit lane.

An average vehicle traveling at 60 miles per hour takes 302 feet to safely come to a stop.  Reference  

The USDOT requirement for an exit ramp distance if the posted speed is 60 miles per hour and the exit ramp is relatively straight is less than 200 feet. Off Ramp Reference

I also checked the driving rules.  Were my teachers overly cautious and/or wanting me to be overly cautious?  Nope--on a "learn to drive" website it instructs students to move into the exit lane prior to slowing down.  Student Reference 

What does all of this mean?  Obviously I need to not be in such a hurry in the mornings, but in addition to that, we need to be thinking about stopping prior to when we're barreling down the exit ramp towards a line of cars at a red light. 

When do you begin the slow down to exit the interstate?  I'd love to discuss