spraying and cutting weeds?

I have been out of town for a while and came home to about an acre of weeds about 1 foot tall in my driveway. I want to get rid of them and kill them. Should I spray first with Roundup then wait until they wilt and then cut them, or can I cut first and then spray the stubble that is left? The weeds are very unsightly and I want to get rid of them asap, but I want to do more than just cut them so they will not just grow back.

I would spray them and wait until they die before cutting. Then try to capture any seedheads if it's seeded out.