A road undivided ?
"a two-lane undivided highway for our readers abroad"
Erm.... El Reg. You need to go back to driving school.
An 'A' road can be either a single carriageway (without central reservation) or dual carriageway (with central reservation).
And no, "single" doesn't mean one. And "dual" doesn't mean two. The differentiating factor is the presence, or lack thereof, of a central reservation. So a four lane stretch of road with no central reservation is a known as a single carriageway.
Not knowing this is a big FAIL in terms of your knowledge of the highway code. Because, amongst other things, failure to be able to tell the difference between a single carriageway and a dual carriageway can result in you exceeding the speed limit.