Is there a map of all the points at which it's possible to get onto Interstate 88?
I was about to start making my own, so I searched for high-res images of the Burnout Paradise maps.
What I found instead was an answer to this question:
http://www.senocular.com/burnout/?load=i88.xml
It's not the most readable, but it does appear to be comprehensive. It also doesn't seem to indicate the path one must take to get on/off at the trickier points. Still, fairly useful.
Bonus: there are lots of other Burnout Paradise maps linked at the bottom!
I don't ever remember seeing one. Most of the maps I found online never quite met my needs.