I think the green lights were the main cause of the fast pace. Momentum is a wonderful thing. Try the ride at the same time sober and your time might be faster.
I too am guilty of having a few too many and riding in the past. I am in no position to preach.
The real issue is not if you can hold a straight line, I am pretty certain I could as well after seven drinks in a night of jubilation. The problem is reaction time when something goes awry. There is plenty of anecdotal evidence of reduced reaction time while intoxicated. When bad things happen fast reaction time is critical.
By the way... Thank you for not driving