I saw these on the news a short time ago.. interesting articles regarding teh EDR:

http://cbs4boston.com/seenon/local_story_296220911.html

"In the Zimmerman case, the EDR data indicated her wheels were spinning at 58 miles per hour, not 40. Her lawyer says that’s because she was skidding on ice, not because she was speeding. But with her own vehicle used as evidence against her, Zimmerman was tried, convicted and spent 100 days in jail."

--------------------------------

I watched the following below on TV. The TV covered a lot more information regarding the speed the was going vs. the speed reported by the EDR than what the article talks about.

http://www.wthr.com/Global/story.asp?S=4104695
" It became an independent witness to what Mr. Matos' car was doing five seconds before the crash. Matos claimed he was driving 60 miles an hour, but the electronic device told jurors he was going 114 mph down a neighborhood street."

--------------------------------

I guess in terms of speed, the EDR can only record how fast the tires are spinning and not the actual forward speed of the vehicle. I imagine in the first article, the EDR should have showed a speed of 40mph and then quickly go up to 58mph when the lady hit ice, but if it only recorded a certain timeframe, it may not have recorded back far enough to show it.

As for the 2nd article, going 60 vs 114mph is night and day, and I tend to believe the EDR at this point.