Not really. A country road, A, B or lower class, may be a 60mph limit. It could well be legal to cycle along a dual carriageway, where the limit might be 70. Not pleasant, or sensible, but legal.
As an aside, last summer I needed to ride down to the edge of Sheffield which involved crossing the A1. There were a few potential crossing places, the first of which was effectively a crossroads where two minor lanes meet at the A1. Legally, I could have crossed there, but google street view confirmed my suspicion that at that point the A1 is a dual carriageway, very wide, 70mph, with a gap in the central reservation. I've driven that bit, there are signs warning of pedestrians crossing, but you could wait months for a safe gap in the traffic.
In the end I had to use a footbridge, that had a ramp, comprised of shallow steps. Only in the UK....