Today, in Delaware, Ohio I was behind a vehicle exactly like this. You could just bearly read where the stickers said, "Traffic Enforcement" on the blue and white vehicle.
It was really cool to see the guy buzzing down the road, quickly. It took everything my car had to keep up with him in traffic as he switched lanes quickly and did 70 mph. The coolest part was the knowing wave that he gave the Smart Car that he passed.
Does anyone kow anything about these vehicles?
EDIT: Here it is a Go-4 Interceptor http://www.westwardindustries.com/
On ebay for $5k. It seems that they go $25k in full police package http://cgi.ebay.com/ebaymotors/2003-Go-4-Interceptor-II-Parking-Enforcement-Vehicl... Another on ebay http://cgi.ebay.com/ebaymotors/1992-GO-4_W0QQcmdZViewItemQQcategoryZ6737QQihZ013QQ...
Other samples http://www.kruse.com/results/return.asp?MAKE=GO-4&RESULTS=1
What I read says that they are governed at 40mph but the one I saw was doing 70mph and accelerated like it could go higher.

