Road width

Is there some kind of federal standard of sorts? We live in an area where the county does not maintain our roads. I volunteered to trim the trees back to widen the roads. I have been told that a 30 foot easement, on each side of the centerline of the road, is the "standard" for your standard, typical neighborhood road. Where I was just hacking away the road surface is a total of 30' wide. The trailer was on the road surface and the UPS truck was able to get by with room to spare. 60' wide seems awful wide for a 2 lane road. I looked at the neighbor that was telling me this like he was on crack but.......