I know this stretch of road very well as I used to live just a few miles down the road in Sale; it's a very dangerous road even more so when wet, which being in England is most of the time.
They called it a dual carriageway (divided highway) but in reality it's not, it doesn't have a central reservation or median. It's a four lane road with two lanes on each side, the lanes being separated by two white lines.
With a speed limit of 60 or even 70 mph, crossing into oncoming traffic is always going to be serious with more often than not fatal consequences as in this case. Sorry to read about a fellow Lotus driver passing away.