As mentioned by several others, this falls under substance abuse policy because it is Edwards' first DUI. The official NFL policy is that first time offenders can be fined up to $50,000, with suspensions happening only after a second offense. The first DUI would fall under the league's Substance Abuse Policy; a second offense would come under Goodell's Personal Conduct Policy.
Goodell is not playing favorites here. For example, Ronnie Brown and Will Allen both also had DUIs this year. In both cases it was their first offense, so neither was suspended; presumably they both entered the first phase of the league's Substance Abuse Policy which includes testing, counseling, evaluation, etc. A second offense gets a four game suspension and a third offense would result in a one year suspension.
There is a gray area regarding Edwards' case, however. He did have a previous assault charge, to which he pled no contest. That means in the NFL's eyes he could be considered a two-time offender, which would fall under the Personal Conduct Policy. He was also pulled once over for driving 120 mph, though I doubt speeding tickets would fall under that policy.
Unless there has been a change in the pattern of how Goodell is handling this case in comparison to others - which I don't see - then there's no point in questioning why Edwards has yet to be suspended.
