Monday 31 August 2015

To Bypass Or Not To Bypass - What Is The Answer?

Last week saw a lot of miles covered, with the first part of the week being a dash to Deventer in the Netherlands and the second part being back in Blighty (which is derived from Urdu if you're interested!)

The UK trip was mainly to see family, although there was a chance for an evening climb of Glastonbury Tor, as well as a day spent at the wonderful Stock Gaylard Oak Fair in Dorset (which I wholeheartedly recommend). But this is about transport, not days out. Driving down to the Southwest from London, we inevitably ended up on the A303 (which always has us think about the Kula Shaker song). The A303 is much nicer route than the motorways, at least until it goes to a single lane road at Countess Services where it is pretty much guaranteed to grind to a halt during peak holiday time. Dorset and a much wider area is bounded by the M3, M4 and M5 and with no motorways within, relies on the A-road network taking the strain.

Approaching Stonehenge on Salisbury Plain, my mind was cast back to the debate about what to do with the A303 as it passes the UNESCO World Heritage site and indeed some of the villages (which is in many ways a more important issue). The monument used to have a road on each side, but one road (the A344) has recently been removed along with a revamp of the visitor facilities (see Google Streetview from 2011 and 2015. 

It's amazing that we can make radical changes like this when we want to for a pile of old rocks (I'm being flippant). The A303 is still awful, but the loss of the A344 makes it a bit less awful and the junction with the A303 had a high casualty-rate. Mind you, with people slowing to walking pace on the A303 to take photos, it's no wonder that there are still crashes. Not everyone is happy, the Stonehenge Traffic Action Group (STAG) has claimed that the closure has pushed more traffic into local villages which would have used the A344.

Winterbourne Stoke lies to the southwest of Stonehenge and is split by the A303. It contains a plethora of traffic signs and road markings attempting to slow drivers as they pass, although the speed limit is 40mph. There have been countless crashes and many fatalities on the A303 through the village in recent years and so not surprisingly, there is a sister campaign group to STAG, the Winterbourne Stoke Bypass Angst (WiSBAng) campaign. This section of the A303 carried just over 12,000 vehicles per day in 2000, rising to nearly 20,600 in 2014; although there has been some fluctuation over the years. 2002 saw 21,300 vehicles per day. An interesting comparison can be had with the Victoria Embankment in London which carried nearly 20,000 vehicles per day in 2000 and nearly 29,000 in 2014 (peak of over 42,000 in 2007).

It seems that there are friends in high places as work to the A303 has featured in the Government's road building plans, although the announcement was made in the last parliament. For Stonehenge, there are options involving tunnelling which would allow the landscape around the monument to be restored to an open setting, although the cheaper options mean major road-building within the World Heritage setting and groups such as the Campaign for Rural England are concerned about this and the wider road-building agenda. Mind you, the scheme has been on and off the roads agenda over the years - the Campaign for Better Transport celebrated its shelving in 2007.

Useful guardrail this, there is a drop down to the road!
So, to Glastonbury, which was a stopover for our trip and so there was just enough time between dinner and bedtime for a walk up the Tor

We walked along Chilkwell Street which is on the A361, before turning off to get to the Tor. The road passes to the south of Glastonbury, but new development has spilled over to the south and so the road splits the area in two. As we were walking back after our climb, I noticed posters in many of the windows in support of the "Lighten the Load" campaign to get freight traffic routed away from the town. The A361 doesn't have a high casualty rate (at least compared to the A303), but if our snapshot walk is anything to go by, I could certainly understand why people want change,

Awful photo of a 40 tonne lorry!
The reason why was soon brought home when two 40 tonne lorries went by, neither of which kept to "their" side of the road because of its narrowness. The photo to the left is on a raised walkway where the lorries didn't bother us (but the footway on the other is a different matter), but before we got here, the footway was so narrow that my group stopped and backed against a wall to let a lorry pass. Pretty scary for adults, let alone the kids.

Interestingly, the Lighten the Load campaign is pragmatic about the possibility of a bypass. There has been lots of talk over many years, but for the Southwest, Glastonbury doesn't appear as a priority. The campaign wants a 7.5 tonne weight limit to stop long-distance freight traffic passing through, although because the route is meant to be freight, the campaign worries that it won't be looked at. I don't know where this HGV traffic is going to or coming from, but a weight limit would need to be strategically placed and other places may be impacted. According to DfT data, the A361 carried 6,500 vehicles per day in 2000, which rose to 8,150 in 2014. HGV traffic varies over the time, but is about 6.5% now. LGV traffic (3.5 tonnes to 7.5 tonnes) is around 15%.

I tweeted the photos from Glastonbury which prompted opinions to the effect of tough, the people chose to live there and do they not shop in places which are serviced by these trucks? Now, it is a point I understand, but equally, why shouldn't people wish to improve their local environment? Our reliance on commodities shipped across the world and then delivered by the largest vehicles possible has crept up on us, along with the de-facto replacement of rail and passenger freight with motorways and trunk roads. I would not even think about doing the trip we did by train as it was done on a single tank of petrol (yes, the cost of running a car is more than that). 

Of course, despite having 6 of us in the car, we still added to the traffic jams, pollution and road danger. I am no fan of road-building, but I am struggling to find answers to Stonehenge and Glastonbury which don't involve road building. Perhaps my problem is that I am thinking about the places in isolation when I should be thinking about the road network on a county or regional level. The problem is the M3 ends up (ish) at Southampton with the M5 at Exeter; and as I have stated, Dorset and the wider area doesn't have motorways, although as a tourist, I can't say traffic jams are ever a major problem (but I don't live there).

If the traffic flow could be cut in half through Winterbourne Stoke, it would still be awful for the village. For Stonehenge, we could further ruin the landscape with a bund to stop the rubber necking. Perhaps a bypass of the area is the right answer. Perhaps rebuilding branch lines to these places and low rail fares will get tourists off the road network. Perhaps, tourists should stay at home, I just don't know. Tunnels are very expensive, but Stonehenge is an asset for the World and so is doing nothing really an option? I can imagine a tunnel, but with a cycle route left along the A303 so people can more gently stop and wonder at the monument.

For Glastonbury, is it right that long distance freight traffic passes so close to homes and the toes of cowering pedestrians, or is it tough? The country needs to function and freight needs to be assisted to keep the price of things down, especially with global competition.

The answers here are going to be beyond transport and into what society wants. The day at the Oak Fair showcased all sorts of products and produce from the local area. An oak picnic table caught our eye and we asked the chap on the stall where the timber came from. His answer was within three miles of the showground. This must be a clue to at least part of the answer. What do you think?


  1. Nice article. You should have gone to Lyndhurst while you were in Southampton, it could probably fuel about 10 blog posts ;-). At work we are currently working in the New Forest area and have to drive through it every time, spending at least half an hour sitting in stop/start traffic as we travel south into the village on the A337. You can see the tailback on google maps From there, the A337 turns left after traffic lights into the one-way, single lane High Street. Sadly, Streetview doesn't show the many HGVs that use it. Two major roads, the A337 and the A35 go directly through the village around a hideous one way system. Apparently a bypass has been thought about for decades, but the New Forest Verderers have great power over development and have always rejected it. In my opinion, I don't really want to see more development in the New Forest, but there needs to be bypasses because it should have been done that way in the first place. Through traffic would then be greatly reduced, and the one-way system can be kept but with cycle tracks. At this rate though, it will still be full of cars for the foreseeable future.

    1. Heh - I think my family put up with enough of me stopping to take photos of things! (If I have a planned trip on my own, I do see there is something to look at for a blog post though - everything being a learning experience and all that).

      I didn't really reach a conclusion with this post as I think the answers are complex, site specific and region specific. Take Dorset. No motorways, but there is congestion at certain places at certain times (like anywhere really), but its charm would go if the roads where made huge.

      We know about induced demand when roads are built and so I think we need to be far cleverer. Perhaps we need to move existing long-distance capacity around centres of population (bypasses!) and then change the areas bypassed to prioritise local journeys by foot, bike and bus.

      The other thing has to be looking at how we consume - Dorset has a reputation for promoting and nurturing local produce for example and so miles and lorry movements can be reduced.

      It is probably about transport being more integral to life than it is now, but while we can (and do) buy cheap stuff containered in from the Far East, I fear things are unlikely to change much.

    2. Problem is, this requires joined-up thinking. It needs Highways England and the Local Highway Authority to come together to create holistic schemes and stop eyeing each other with suspicion and paranoia - each thinking that the other is out to screw them in some way. The irony being of course that the money for both of 'their' highways networks comes from exactly the same place, the UK taxpayer.

      Andy R.

    3. Well yes, it is only one pot of money, although don't forget developers who end up stumping up towards improvements sometimes. The problem is the whole thing is skewed by the government's capacity adding agenda which is not addressing what happens when extra traffic is spat out into towns.

  2. Bypasses would be easier to support if they weren't such trojan horses.

    How often does a two lane road through a town become a bypass with four lanes thereby increasing road space and inducing demand?

    The bypass then becomes the boundary for infill development, sometimes urban sprawl. Junctions get built on the bypass making it inefficient for the long distance traffic it was built for. Retail sheds get built causing congestion and demand for a further bypass or rat running through the urban area that was bypassed.

    If the original route was closed off to through traffic a bypass might improve the town being bypassed but that never seems to happen.

  3. Spot on there. If road capacity is shifted from residential areas and other places we don't want it to a bypass then fine as traffic and congestion in any given place generally finds a level, but where the "old" routes bypass the bypass then we have two congestion points instead of one away from where people live. But we don't do that here. Sigh.

  4. Interesting post. I can't believe the answer to any of this is to build more roads - if that was the answer then these questions would have been resolved by now. It seems to me that we plan our transport without reference to its wider implications and impacts - on our communities, local economies, on the health of the population etc etc. We need to start planning from the other end - decide how we want out civic space to function, what our ideal of for a local economy might be, what sort of health outcomes we want to prioritise and then organise our infrastructure accordingly.

    1. It was an interesting to write the post - I challenged by own views. I am generally against road building, but thought bypasses here could help. Actually, I think the engineering answer is a bypass, but with no capacity increase as such *and* preventing through traffic in the place bypassed to return it to local active journeys. Plus, returning to using resources locally will be the social and economic reason why new road space is not needed.

      So, I am not against new roads I suppose, so long as they are built for the right reasons.

    2. I know Glastonbury quite well - I actually lived on Chilkwell Street as a child. The town already has a bypass along it's western edge and a second could be built from the A361 across the moor to join the road between Glastonbury and Street. That road then runs through a string of villages to join the M5 at Bridgewater. So it seems more like moving the problem than solving it. I live near Bath and a village on the A367 south of Bath had a bypass built. That bypass now has a private hospital, 2 large garages (Mercedes and Audi) and a small industrial estate on it with more development planned. All of these generate traffic that comes from and passes through other places that don't have bypasses and probably won't get them. All of these are journeys created by the bypass and are additional to the traffic problem the bypass was built to alleviate.
      I'm unsure just how a bypass can be built 'with no capacity increase' - that can be the intention but our whole transport system seems riddled with unintended consequences.

  5. Hi Ranty!

    Good post. I do think there needs to be a distinction between "road building" for capacity's sake (M25 upgrades and such) and simply bypassing motor-traffic-choked towns and villages without adding more lanes/grade-separation. Upgrades of long sections of road are much more expensive than simply making a single carriageway bypass around a village.

    Does induced demand really apply to bypasses? (I usually refer to it as the Fundamental Law of Road Congestion - there is plenty of American research behind it, and their highways are bigger than ours!). Travel times may decrease (40/60mph bypass vs 30/40mph A-road through the village with pedestrian crossings and so on), sure - but so what? If I lived in a small town/village with a busy A road passing through I wouldn't care how much traffic increases on the bypass when it is built - the important thing is removal of the motor traffic (especially freight) going through the village. As a motorist, I would also appreciate removal of bottlenecks/slower sections of road.

    Regarding rat-running through towns, I would always opt for minimal motor vehicle permeability. If a rat-run route exists, it will get used when the bypass gets busy enough, even if it only saves a couple of minutes. Just have one way in and out of the village onto the bypass road for motor traffic, problem solved.

    If a bypass and a rat-run route both exist, Braess' Paradox may kick in: Especially when junctions are on the same level - e.g. if the two ends of the village end at roundabouts onto the bypass, bypass traffic may at some points have to give way to rat-running traffic. Conversely, priority junctions where village traffic always gives way to the bypass could make the bypass difficult to get onto. Forcing motorists to go a tad longer way around (one way in and out of the village) is also a good way to incentivise cycling/walking instead.

    Braess' Paradox can also be a good way to argue for simplifying a town's road network for motor vehicles to make space for cycling possible. We already know that junctions are generally more(?) efficient with less arms going into them anyway - and changing a T-junction into a free-flowing straight section of road (except cycling/walking) is also nice for motoring (unless you are trying to drive a really short distance - again, incentivise cycling/walking).

    1. Thanks for the comment and for introducing a new concept to me. I do believe this is where my thinking is going and there are parallels to the Dutch concepts of simplifying the networks for function. Yes, so what if the bypass is busy, we have freed up a more livable and safe town.

    2. I've heard of Braess' Paradox but is it possible to predict if its effects may occur in a particular situation? Or does it generally just reveal itself after roads are closed because modelling can't handle it?

      I'm involved with a residents group trying to close a rat run along our street and it seems like the council traffic planners view the street as a de facto relief road for the main route. Closing the rat run would mean more traffic on the main route and that would be bad because it will mean more delays on the main route.

      Braess' Paradox could actually mean that closing the rat run will speed up traffic on the main route, but is there any way of proving that? Or at least figuring out a probability that it may occur?

    3. Well, this is beyond my knowledge (I'm a kerbs and tarmac bod!) It is worth having a read around traffic evaporation which is also applicable in this kind of case. Forget, flows, modelling and so on, focus on what the local street for?

      One person's rat run is another's journey to work and that is what the "fight" is about. Rat ran is becoming emotive so perhaps look at this website for some different language about the function of streets and it has useful figures:

  6. I'm an engineer and I like mathematical approaches! However in this case, anything I could do would be purely theoretical and not much use so I agree with you that the best approach would be to focus on the function of the road and the human impact of the traffic.

    However I can't totally give up on numbers and it has been interesting looking at DfT vehicle counts for the streets concerned. Vehicle counts have been decreasing since 2000 and the total vehicle counts for the main route plus ratrun in 2014 is the same as just the main route in 2010. The implication being that closing the ratrun would bring traffic on the main route back to what it was in 2010. And if it was acceptable then, why not now...?

    1. That is a very good argument. The DfT figures are not totally reliable (read their own spiel on why), but this can be compelling. I find people often say they don't agree with data (i.e. facts and logic), but it makes it hard to argue convincingly.

  7. The Dutch are so committed to their roadway safety. 80 km/h on single carriageways is a big improvement over 100 km/h for most routes. A few mostly divided expressways sometimes with hard shoulders and more grade separation and very little if any local access makes their 100 km/h single carriageways much safer than British ones, these routes being the main ones for the provinces, similar to A roads in Britain. Many other routes are 60 km/h single carriageways, used for local access and as main routes between villages, usually like B roads. Few routes are 4 lane divided expressways without being full motorways in rural areas, though a few are in Zeeland and the Northeast.

    Motorways are of a high quality, link every province in complete routes, and is a pretty dense network, with electronic control for the most part, 120-130 limits for most of the network, a few 100 km/h routes, and even in cities they usually get up to 80-100 km/h, whereas Britain often goes down to 40 mph. And by in cities I mean usually bypassing them, as they do with most main routes. Many villages, towns and cities have a bypass or sometimes full ring roads. Roundabouts are used often to keep the conflicts down, and on most 80 and 60 km/h roads, other than a few country back lane 60 km/h roads (which is much better than high volume 100 km/h roads) there are parallel bicycle pathways. Bus routes are often used in rural areas to connect places the trains which are usually 120-140 km/h electrified routes, a few go up to 160, and most routes in the city can go at least to 80 km/h, a number of them up to 120-130, on twin track routes which are fairly straight lines, with almost all level crossings being protected with signal arms and boom gates, and more and more grade separated crossings exist. Frequencies are usually at least one every half hour, some go every 15 minutes.

    And of course there are many bicycle paths as well. As I mentioned before the continuity of routes throughout rural Netherlands is extensive, and works well as a grid that links every home and destination. The OV Fiets system works well as a nationwide system with no frills low maintenance bicycles (single gear, backpedal brake only, hub dynamo, mostly metal, lock included) that can be acquired from most railway and some bus stations.

    It makes getting around the country by any means much safer than Britain has, and also often quite a bit faster.

  8. Thoughtful article, thanks. I just wrote a post on a proposed bypass for Glastonbury, you might find it interesting.

    1. Thanks for the link Vicki - I've put it out on Twitter as people need to know - it would be awful for the town.