Before the nice section of A30 HQDC between Honiton and Exeter opened in 1999, would it have been quicker and easier for traffic coming along the A303 from the M3 and South East to leave at Southfields roundabout and take the A358 to M5 J25 and then head south on the M5 rather than continue on the A303?

When travelling to the SW on family holidays in the late 70s/early 80s (ie after the M5 was completed), I always remember we took the A303/A30 all the way to Exeter, even though the old A30 between Honiton and Exeter wasn't that much better than the current Blackdown Hills section. Surely it would have been better to cut out that bad part west of Ilminster and hit the M5 sooner, even though it would have been 9 or so miles longer?

Did signs encourage Exeter traffic to go any particular way (A303/A30 v A358) back then? Would the DoT have wanted to keep as much traffic as possible from the Blackdown Hills? Or were they afraid of overloading the M5 south of J25 with both A303 and M4 traffic?

What would sat-navs have suggested if they'd been around in those days ?

I've been going to the South West since I could drive (1982). In the early days I came from Essex and took the M4, M5. Latterly I went with a friend who lived in Surrey (1986) and then living in South London (1989 onwards), I and others of my acquantance always used the A303 along all its length.

The thing is; leaving early and not going in the school holidays meant that at those times the A303 wasn't that bad through all the single carriageway parts and it never seemed worth diverting onto the A358.

In answer to your particular question: the signs have pointed to the M5 via the A358 for many years and I believe pre 1999. I don't know about sat navs but in the early days of Multimap direction finder, it did everything to keep you off the A303 and always wanted you to take the motorway. I assume had sat navs existed in general use then, they would have done the same.

Traffic has increased since those days and I mostly have to go in the school holidays. So that now I have resolved not to use the road at all.

The signs never suggested going via the A358 to the M5 (Taunton) and don't now.

That said some drivers still do go that way to avoid the Blackdown stretch and have done since the Hatch Beauchamp and Ashill bypasses were built in the 80's (before that the A358 was worse than the current A303 through the Blackdowns)

I suspect such use is diminishing now though due to the increasing congestion on the A358. It is not unknown to have a mile of slow moving traffic at either end.

I think that it is important to point out that at Ilminster traffic for the M5 is signposted along the A358, but traffic for Exeter, and thus the A30 and A38 south west of there, is signed along the A303.

It really depends on where in the South West you were going and where you started from. My journeys started close to the Surrey/Hants/Berks meeting point and went to Bridport, so it was either the A303 or the M27/A30/A35.

However people going beyond Exeter would often opt for the M4/M5, particularly if they were prepared to pay for getting there quickly.

Certainly since the NDLR was built more traffic has used the A358 link, but for west of Exeter that is a long detour. I have been travelling regularly to North Cornwall since the early 90s, and have variously gone M4/M5/NDLR, Ilminster/Taunton/NDLR, Langport/Taunton/NDLR, Blackwater/Wellington/NDLR, Honiton/Okehampton/Holsworthy or Honiton/Okehampton/Launceston/A395.

While the M5 is at times quicker, it is not very pleasant, and you run the risks of hold ups on the increasingly congested A358 making it slower.

In the Mon - Fri rush hour in particular the A303 through the blackdowns is clear and the A358 congested.

On summer saturdays it can be the reverse but you only need a minor prang on the M5 which on Summer Saturdays is a 60mph rolling traffic jam and you have hours of delay.

The other option on Summer Saturdays is of course the A30 rather than the A303 which is not particularly fast but not particularly congested either.