What if the UK’s motorway network had followed the “Neubaustrecke” concept?

[PTR 444]

…Or the Autobahn equivalent of that word.

Inspired by a similar thread on HS2 from a few months ago, I’m wondering what might have happened in an alternative scenario where Britain’s motorway network was planned as a series of incremental bypasses paralleling the existing trunk road network, rather than full blown new-builds. For example, instead of the M1, let’s say we had a fully dualled A5/A45 between London and Birmingham with the A6 also dualled from London all the way to the East Midlands.

This is essentially how the Republic of Ireland built their motorway network, by stringing together bypasses of existing trunk routes and allowing them to retain the same number (N1>M1 etc). If more radial routes out of London were upgraded in this way, we’d have better contingency in the event of disruption and closures. For example having two London - East Midlands motorways (one via the A5/A46 corridor and the other paralleling the A6), but would the cost of an overall bigger motorway network have been worth it?

 

[Bletchleyite]

You can see that in action (and still progressing) on the A1/A1M.

 

[randyrippley]

The early stages of the M6 and some other motorways were exactly that. New bypasses around Lancaster, Preston and other northern towns gradually linked up. However actually upgrading the old A6 itself would have been impractical due to the destruction it would have caused to so many town centres.
It would have taken time as well: the A1-A1M upgrade is still in process now, something like 60+ years after it started

 

[PTR 444]

The early stages of the M6 and some other motorways were exactly that. New bypasses around Lancaster, Preston and other northern towns gradually linked up. However actually upgrading the old A6 itself would have been impractical due to the destruction it would have caused to so many town centres.
It would have taken time as well: the A1-A1M upgrade is still in process now, something like 60+ years after it started

To be honest, I doubt a motorway paralleling the A6 through the Peak District would have got past the planning process. It might have been the case that a Derby - Manchester M6 followed the A52/A523 corridor via Leek, with the Peak District A6 downgraded to an Axxx number.

 

[thejuggler]

Similar to HS2 argument that it was quicker to build new than disrupt existing roads for years, you also need to remember some traffic isn't allowed on motorways.

A1 mentioned above is a classic case. Upgrading to full motorway isn't possible for long stretches because it would need another parallel road for excluded traffic, in particular the many agricultural vehicles that use the A1.

 

[The exile]

anyone who remembers the Exeter bypass just before it was bypassed by the M5 will tell you what happens when a motorway disgorges itself onto an existing road system.
Also - the main trunk roads served the needs of the 18th and 18th centuries which were not always the same as those of the 20th/21st.

 

[61653 HTAFC]

It's rather charitable to assume that the numbering system would make more sense from this approach. There is after all a numbering system in place but it hasn't been adhered to everywhere. For example the M5 should really be the M38 as it parallels the A38. The M5 should be in North Wales. Similarly the M606 (the Bradford spur motorway) should be the M638 after the A-road that runs parallel.

 

[stuu]

It's rather charitable to assume that the numbering system would make more sense from this approach. There is after all a numbering system in place but it hasn't been adhered to everywhere. For example the M5 should really be the M38 as it parallels the A38. The M5 should be in North Wales. Similarly the M606 (the Bradford spur motorway) should be the M638 after the A-road that runs parallel.

The motorway numbering is distinct from the A/B numbering, so the M5 is correctly numbered

 

[Magdalia]

The old trunk road network dates from the era of stage coaches. They went from town to town in stages, the length governed by how far a team of horses could draw the coach.

What is the argument for slavishly retaining that constraint with motorised transport?

The UK trunk road network is a pragmatic mixture of following old routes and building new routes. Although not a motorway, the A14 is a good example. It is an upgrade of existing routes between Ipswich and Huntingdon, but the Ipswich-Felixstowe and Huntingdon-Catthorpe sections are new road.

 

[AlastairFraser]

…Or the Autobahn equivalent of that word.

Inspired by a similar thread on HS2 from a few months ago, I’m wondering what might have happened in an alternative scenario where Britain’s motorway network was planned as a series of incremental bypasses paralleling the existing trunk road network, rather than full blown new-builds. For example, instead of the M1, let’s say we had a fully dualled A5/A45 between London and Birmingham with the A6 also dualled from London all the way to the East Midlands.

This is essentially how the Republic of Ireland built their motorway network, by stringing together bypasses of existing trunk routes and allowing them to retain the same number (N1>M1 etc). If more radial routes out of London were upgraded in this way, we’d have better contingency in the event of disruption and closures. For example having two London - East Midlands motorways (one via the A5/A46 corridor and the other paralleling the A6), but would the cost of an overall bigger motorway network have been worth it?

I think we would have ended up with a network not dissimilar to today's network - there are still sections of the classic trunk road network that pass through national parks and other protected areas.
It also needs to account for the fact that the classic trunk road network in the UK doesn't serve many sizeable settlements, so new build would be needed in those areas too.

 

[NoRoute]

I would expect average speeds on a journey would be a lot lower because an incremental approach is very unlikely to deliver a continuous motorway, free from junctions interrupting the flow of traffic. Looking at the major roads which have grown incrementally, they tend to have a lot more roundabouts or other junctions along the route, slowing down traffic, adding to congestion and increasing journey times.

 

[swt_passenger]

Similar to HS2 argument that it was quicker to build new than disrupt existing roads for years, you also need to remember some traffic isn't allowed on motorways.

A1 mentioned above is a classic case. Upgrading to full motorway isn't possible for long stretches because it would need another parallel road for excluded traffic, in particular the many agricultural vehicles that use the A1.

I think they eventually achieved that parallel road on the northern 90 miles or so, Darrington to Birtley. So it’s always possible they’ll do more.

 

[paul1609]

…Or the Autobahn equivalent of that word.

Inspired by a similar thread on HS2 from a few months ago, I’m wondering what might have happened in an alternative scenario where Britain’s motorway network was planned as a series of incremental bypasses paralleling the existing trunk road network, rather than full blown new-builds. For example, instead of the M1, let’s say we had a fully dualled A5/A45 between London and Birmingham with the A6 also dualled from London all the way to the East Midlands.

This is essentially how the Republic of Ireland built their motorway network, by stringing together bypasses of existing trunk routes and allowing them to retain the same number (N1>M1 etc). If more radial routes out of London were upgraded in this way, we’d have better contingency in the event of disruption and closures. For example having two London - East Midlands motorways (one via the A5/A46 corridor and the other paralleling the A6), but would the cost of an overall bigger motorway network have been worth it?

That's really how the M20 was done. The Maidstone bypass was built as the A20(M) before being absorbed in to Junctions 5 to 8 of the M20. The spur road to the A20 at junction 8 is the old motorway terminus including the overbridge. The A20 Ashford bypass was absorbed in to the M20 for a section north of junction 10. The first section of the M26 at the M20 end was originally part of the M20 which is why the M26 s only intermediate junction is 2A. The section past brands hatch was originally built as the West Kingsdown bypass and ended at a set of traffic lights on the single carriage A20 proudly proclaimed as Temporary Motorway Terminus. Junction 1 to 2 also formed part of the London Orbital until Junction 3 to 5 of the M25 opened. Part of that was built on the A21 Sevenoaks Bypass hence the weird totso junction 5 and the secret a21(M).

 

[Snex]

I think they eventually achieved that parallel road on the northern 90 miles or so, Darrington to Birtley. So it’s always possible they’ll do more.

Barton (just north of Scotch Corner) upto Whitemare Pool (end of A194(M)) was a brand new road as much as the M6 is in Lancaster / Cumbria. The old road is the A167 which is quite a bit West so wasn't really an upgrade of the old road.

 

[mike57]

I think the issue is that by the time motorway building started the existing trunk road network would have been hemmed in by development, so you would be starting from scratch anyway.

One of the failures of the road building program was the failure to finish the A1 upgrade which was started and well underway, but seems stalled, particularly south of Doncaster, this I think is a failing of peicemeal upgrades, the job doesn't get finished, and the delivery cycle is longer than the political cycle, so a change of government halts everything.

 

[david1212]

The A449 from Wolverhampton to Penkridge and the A34 from Stafford through Stone to Newcastle-under-Lyme are dual carriageway and mostly could have been widened to three lanes then add a Penkridge - Stafford bypass on the current M6 route. First slower in parts due to passing through villages and along the topography plus second would not cope with the combined volume of traffic.

Over the years from 1960's to 1990's the A34 from Oxford to the A33 was effectively built as it is now as a series of bypasses e.g. Newbury, East & West Ilsley linking widened sections of the existing route. Even as two lanes it could be reasonably now be 'M' numbered e.g. M34 other than not having a hard shoulder or even regular refuge bays.

Some trunk roads now follow a significantly different route than 50+ years ago e.g. A46 from Warwick to near Tewkesbury via Evesham then disappearing instead of via Stratford-upon-Avon and Broadway into Cheltenham. From Cheltenham it restarts on the original route to Stroud and Bath. This is an example of a route that could not have realistically been upgraded instead of the new build M5. As mentioned already the same applies to much of the A38 too aside from the disruption. From Coventry to Leicester the A46 disappears again replaced by the M69, a new build rather than trying to closely follow the A46 route from Coventry to Leicester.

 

[fandroid]

Around my way the problem is that parts of the A30 have gradually filled up to being as busy as they were before the M3 was built. And it still has most of the faults that made it a more accident-prone route than the motorway.

It would have been far better to have downgraded it at the time to be primarily a combined safe route for public transport and non-motorised users, designed in such a way that it could temporarily revert to taking some motorway traffic during closures after accidents