A recent case in Iowa. A pickup truck driver pulled out from a side road into the pat of a motorcycle. The two people on the bike, Florida residents Benjiman D'Amico, 58, and his wife, Linda, 59, were both killed. The local prosecutor determined that it was an accident, the driver didn't see the motorcycle and that there were no grounds for any other charges except failure to yield. In the end, two motorcyclist lost their lives, and the driver was fined $65.
Involuntary manslaughter sounds like a good start to me.