benefit - let's start with reduced blood pressure and reduced frustration.

The A251 is a narrow A road, linking the M2 and M20 motorways beteween Faversham and Ashford. It's full of bends, pases a few hamlets and has a long hill at the Ashford end. In a car the speed limit is 50 for most of the route, HGV, bus, vehicle towing horse box et al presumably 40, get stuck behind a tractor much slower. Overtaking opportunities are few, long queues of traffic often. If two lorries, busses or HGV's want to pass each other they slow down to walking pace to do so. Nightmare road to use.

It seems to me that far from planners adding extra dualling on rural A roads, they appear to be steadily removing many of the existing sections of dual carriageways. In many places what was the outside lane of a dual carriage way gets blocked off, greatly reducing the opportunities to safely overtake slow moving vehicles.

So a town of 200k and another half its size. How much demand is there for travel between them?

I doubt if there's much demand for travel between Exeter and Worcester. The point is that even if you only need some of the N'ton to KL road for your particular commute you will need almost twice as long than if it was dualled. If we were talking train times, the rail users would be incensed if their journeys were regularly taking over an hour rather than 40mins.

Dunno why there's such an issue these days about lower powered cars, and overtaking ?

For sure, if, by lower powered car, one means, a Citroen 2 CV, then I could understand..although in such a car, properly driven, overtaking is a pleasurable pastime....since it takes skill, amongst other things.

Recently I had the short-term use of a Matiz.....and failed to comprehend how these cars have been vilified. Once I had become familiar with its characteristics, I found I could overtake all sorts...whatever I felt was 'in my way'.....and without having to exceed the proscribed speed limits, either.

Just takes a bit of planning.....something I feel most drivers don't think they should have to do!

The problem to come with A-roads, to me..will occur when LGV speed limits for single carriageways get raised.

Sure as eggs are eggs, LGVs will be thumping along on their speed limiters, [knowing they will get away with it]...and since car speed limits will not get raised in proportion, overtaking will become nigh on impossible [remaining within the Law....]....so average traffic speeds will fall overall.

Comments above about drivers not overtaking, yet remaining too close to the [slower] vehicle in front, I agree with. Very rarely do car drivers simply drop back, to leave a goodly space, for others who wish to overtake, to do so, and pull in, before tackling the 'slower' vehicle itself.

It's why military convoys [in Europe] have that large spacing....

Try calculating the cost of improving those roads (and all the others) to the standard you expect, then calculate whether that would be cost-effective, and finally calculate whether you (and everyone else) would gladly pay the increased taxes?

Much progress in civilised living is not 'cost-effective'. Concorde, channel tunnel, Canary Wharf, most of the rail network and probably much of the NHS come to mind. Most went bust, none turn a profit.

Agree with OP, it is indeed embarrassing to return from driving anywhere in Europe back off the ferry on to our infrastructure. The quality of our road surfaces is generally awful, they are full of potholes,repairs and repaired repairs. There is a section of the A48M near Cardiff that is dangerous, as the O/s tyre line is breaking up for hundreds of metres. Whern I ride my bike, I find I increasingly adjust my position in the road from Position 3 (to the right of the centre of the lane) to the centre strip just to avoid the mess of pot holes and poor repairs. We are supposedly the 4th richest contry in the world, yet our transport infrastructure is still Victorian. Why no 200mph TGV trains here, why no 300 mph Bullit trains? i can't think of a reason other than the hopeless short term political system tied up with a tortuous planning system that won't approve anything. GB has a good point too!

When new roads get built or older ones upgraded, the result is inevitably more traffic than before, because people either believe that a switch from public transport to car will save them a bit of time and money on an existing journey, or actually attempt a journey that would have been out of the question before.

Try 'directions' on Google Maps for a few journeys - Huddersfield Railway station to Sheffield University, for example.

By car, three routes, 56 min to 1 hour, about 1 gallon of petrol, say £6. (you have already paid road tax, insurance and acar will still depreciate sitting on your drive)

By rail and tram, 1hr 39 min to 2 hr 2 min, cheapest single £9.30 + tramfare (£2?)

Back in 1961-4, I travelled this route by train, single fare 6/6d, day return 6/3d, time to Sheffield Victoria station about 50 minutes.

By car, as there were no cameras, fewer speed limits and less traffic, about 40 minutes and about a gallon of petrol, 4/-.

The direct rail route this used (Woodhead/Penistone/Stocksbridge/Sheffield) was closed so now the rail route is via Barnsley.

So public transport was quite competitive, now it is not only more expensive and less convenient, off the main North/South lines its also slower, so not surprising so many prefer to use the car. As a bonus, up to 5 of you can make the journey for the same cost as one, who can afford a family train trip?