No, I don't recommend it. I did the 1/2 in 2005 (when it was combined with the full) and was in AWE of all the traffic!! I would not have wanted to be driving in that mess!
In 2006, after I signed up for the 1/2 but chickened out, we were at Epcot at midnight for EMH the night before the 1/2. They were starting to line the buses up for the 1/2--there were more buses in the parking lot and on the streets waiting to get into Epcot that I could ever imagine. It was pretty cool.