SOUE News Issue 8

Highway Design - Then and Now

Colin Tyrrell (Merton 1964-67)

1967 was not a bad year to become a road builder. The first motorway, the M6 Preston bypass, had opened on 5 December 1958, with the first substantial length of M1, the 67 miles from Watford northwards, opening a year later in November 1959. By 1967, much of the uprights of "H" shape of the M1/M5/M6 in the Midlands were in place, though the tricky bit in the middle did not follow for a few more years.

Further south, not much had been done except for isolated lengths of M4 including the West London elevated section and the first Severn Bridge. The M2 was there, and so was a short length of future M20 around Maidstone.

There were no motorways in Hampshire, where little other road building had taken place since World War II. Design for the future M3 had started, and construction of the A27 Havant Bypass and A33 Otterbourne/Chandlers Ford Bypass was under way though the roads had not yet opened.

Against this background, I set off for interview for a job with the County Surveyor's Department in Winchester. I shared a car with three other Engineering Science students. Much to our surprise we were all offered unconditional places as Graduate Trainees, and started the following August together with five graduates from other UK universities.

It was a different era - all our design work was done in imperial units, most calculations were done using a slide-rule or tables of seven-figure logarithms, and surveying was done using traditional theodolites and tapes. Together with a colleague from Leeds University, I was drafted into the bridge office to help with the design and drawings for a set of three high-skew steel box bridges for the M3 at Popham, just south of Basingstoke. I remember that he was amazed when I asked him what a bending schedule was - it was not a term I had come across during my three years of Engineering Science at Oxford.

We produced our technical drawings in pencil on large sheets quaintly sized in imperial units as double elephant. These were then transformed into silk purses by a formidable team of women tracers who drew in Indian ink on to a stable linen base to produce the masters suitable for the dyeline printing process of the time.

The finished linens came back to us for checking or alteration. On one occasion, I was so embarrassed by a late change due to my error that I decided to make the alteration myself, rather than confess to the tracing pool. I borrowed the motorised eraser they used - similar to an electric drill holding a stick of erasing abrasive. Before I realised what I had done, I had erased right through the linen, leaving a hole in the drawing and a quantum leap in my level of embarrassment.

There was one Anita electronic calculator in the office, which we would queue up to use. These early machines, with a full matrix keyboard and a display of twelve cold-cathode numerical display tubes, were manufactured locally in Portsmouth. They were the size of a typewriter, but were so much quicker and more accurate to use than the mechanical calculators, log tables or slide rules that they replaced. Within a very few years they themselves were entirely obsolete, with the introduction of small hand-held calculators on every desk.

With the detail design for M3 complete, I was transferred to the South Coast Trunk Road design office in Southampton for some preliminary design. This was the first scheme to be designed in metric units - I soon forgot how to convert 7¾" to decimal feet in my head, but had to learn to divide feet by 3.2808312 to get to metres, a conversion factor which remains in the front of my brain some 40 years later. The other big news of the time was that the South Coast Road was now to be a motorway - the M27.

My first major site was the M3 contract for which I had produced some of the bridge drawings, where I was appointed as Assistant Resident Engineer. It was salutary to see the steel-fixers struggling to achieve the framework of large reinforcing bars for the concrete which on my drawing looked so straightforward. I had not realised how unwieldy a large diameter bar could be when it had to be fixed in three dimensions.

Setting out the M3 across many miles of green fields, and ensuring that it was located exactly within the areas of land acquired in the Compulsory Purchase Order, was a skill which my short surveying course at Oxford had not fully prepared me for. Our week of surveying in the Cumnor Hills was a highlight of my first year. The redoubtable Brigadier Bomford, who had been Director of Military Survey in Burma during the war, was our tutor. He started off teaching us all the basics including the use of the plane table to produce direct mapping. After a morning of following him around the fields as we added stations to our individual plane-table surveys, we stopped for lunch. Having eaten his meal, the Brigadier made a discreet move towards some adjacent woodland to answer a call of nature. One of our number who went on to have an illustrious career jumped up, hoisted his plane table, and made off after the Brigadier, only to return shortly afterwards in a state of some embarrassment.

I was working at Popham, just south of Basingstoke, right alongside the old Roman Road. At the time, I was reading the biography of Thomas Brassey, the Victorian railway contractor who built the section of London and South-Western Railway which passes nearby. Whilst he was supervising the works he lived in Popham before moving southwards to Winchester as the works progressed. As I was living in Winchester and travelling up the old Roman Road to Popham to work, I felt some connection with those who had preceded me in building links from London to Southampton.

Unlike the M3 which ran alongside much of the existing A30/A33, the section of M27 I moved to next forged a new route across the Test Valley to the northwest of Southampton. This was the time of the three-day week and rocketing oil prices. The first led to an extended construction period and the second led to a decision to change from a flexible blacktop carriageway to a rigid concrete one. We all had to learn quickly about the complex paving train which formed the complete carriageway in one pass. The process was very different from the multi-layer way a blacktop road was laid, and left no margin for level error.

I was appointed Resident Engineer on my next project, the A27 Lewes Bypass in East Sussex. This was one of the last road schemes to be almost universally welcomed by the community it was designed to serve. The narrow centre of Lewes had been plagued by heavy trunk road traffic, and the bypass had been long awaited. Building a new embankment across the flood-plain of the River Ouse was something of a challenge, given the compressible ground and resulting stability problems. It was 1976 - the hottest summer of the century - and we were transporting 1 Mt of chalk from a deep cutting in the adjoining South Downs. I made a particular effort to keep local residents informed as to what we were doing and why, and I was amazed at the low level of complaints we received even though the inevitable chalk dust made parts of the city look as if they were under snow. When the autumn rains finally arrived, we had two failures of the new embankment. One slip may be regarded as a misfortune; two looks like carelessness, even though it happened just outside the length that had been carefully instrumented to monitor stability.

I had enjoyed my ten years on site enormously, but I accepted that I would have to return to the design office to progress my career. It was at a time of enormous change in design methods and assessment tools, as well as the start of a period when road-building was becoming much less popular.

Environmental assessment of roads had previously been an implicit rather than an explicit part of road design. Most engineers worked closely with their colleagues in the planning department to ensure that new roads were sensitively designed and located where they would cause the minimum of environmental damage. However, there had been some mistakes. The insertion of roads into city centres had in some cases been particularly insensitive. For instance, at the opening of the A40(M) Westway in west London in July 1970, the residents of Acklam Terrace threatened to blockade the road where it ran very close to first floor windows. In those days, there was no power or duty to compensate residents of property which was not physically affected, and the Ministry of Transport refused financial help. At Westway, the tape cutting was only briefly interrupted by protesters who made their point and moved on at police request.

During the 1970s and 80s environmental assessment techniques for highways expanded rapidly, first as part of national best practice and then in 1985 as a result of a European Directive. In 1973, the Land Compensation Act provided a statutory basis for compensation for injurious affection as a result of new roads, and in 1975 the Noise Insulation Regulations came into force. Methods for traffic forecasting were improving, and economic assessment using cost-benefit techniques became more widespread. These did at least serve a useful purpose for comparison between road options, even if the absolute figures over the 30 year assessment period proved to be more suspect.

However, none of this was enough to satisfy the increasingly vociferous anti-roads lobby. Public Inquiries into major road schemes, which in the early days had only taken a few days, became increasingly confrontational, with some objectors apparently convinced that disruption was the most effective way of making their case. In Winchester, there was the spectacle of the M3 extension Inquiry where the Police were called to eject the headmaster of Winchester College. He was intent on saving Winchester's water meadows from further erosion by road building, though they had already been impacted by construction of the Didcot, Newbury and Southampton Railway in 1895 and by the original Winchester Bypass in the 1930s.

He got his way, and in the reassessment of the M3 route in the early 1980s it was agreed that it should be realigned away from the water meadows to run in deep cutting through Twyford Down. Somewhat ironically, although the amended proposals had a reasonably easy passage through the Public Inquiry, they led to even further protest during the construction phase. In the design office in Winchester (now privatised as part of Mrs Thatcher's transfer of design staff from county councils to consultants), we became accustomed to running the gauntlet of angry protestors outside the office.

However, I never did see the parallel of my profession with that of a concentration camp guard, as one protestor screamed at me as I returned from lunch. The first time the protestors broke through security they occupied the ground floor of the office and padlocked themselves to the desks of those wicked promoters of car supremacy: the engineers working on public transport proposals. Those of us upstairs in the motorway design office found this rather ironic.

I think the Winchester College headmaster was probably right about the M3 route, but you may not share my view that the damage caused through Twyford Down was outweighed by the benefit to the water meadows and to the setting of Winchester which resulted from the removal of the old bypass. The railway was closed in the early 1960s, so now there is no major transport obstacle (except perhaps the Itchen Navigation) between Winchester Cathedral and its earlier spiritual counterpart of the magnificent hill fort of St Catherine's Hill. The Centre for Sustainable Transport at Cambridge University has a paper at [Ed: this link no longer exists] which in my opinion gives a balanced view of the story.

The demonstrations outside our office continued during the construction of the Newbury Bypass, which was also designed in Winchester. However, we had it a good deal easier than my colleagues on the site, who among other depredations had to put up with being bombed by urine bags released by the protestors in the trees.

It seemed to me that this was no way to carry out a proper debate on the roads programme. I had taken a few projects through the Public Inquiry stage, and, as well as enjoying the intellectual challenge of presenting a case and being subject to cross-examination, I thought it was a much better forum for intelligent discussion than trying to respond to the shouted insults of protestors.

The Planning Inspectorate, which provides the inspectors for Roads Public Inquiries, had traditionally recruited mainly senior military men on their early retirement from the armed forces. Typically such men had a broad experience, a natural air of authority, and the knowledge and judgement of a successful generalist. However, there was felt to be a need for greater expertise in detailed environmental assessment and in technical matters such as traffic modelling and highway alignment.

The Inspectorate decided to recruit more specialist staff for the task, and in 2003 after 36 years of being a poacher I changed sides and became a gamekeeper. I find this much more to my liking. I enjoy becoming totally immersed in one scheme at a time. I find dealing with barristers and controlling the running of an Inquiry stimulating and involving. Weighing up contradictory evidence and coming to a recommendation can be fascinating, and I obtain particular satisfaction from teasing out the justification for proposals, and sometimes backing the individual objector against the combined might of the promoting side.

Three things worried me when I became an Inspector: the requirement to keep at arms length from all sides, the expectation that the Inspector at least will keep his jacket on, and the worry that after lunch in a hot stuffy hall my eyelids might droop. I have managed to deal with the last two by ensuring that the hall is always well ventilated and, if air conditioned, kept at a chilly 19°C. The requirement to keep aloof from personal contact I find more of a problem. Throughout my previous professional life, I have enjoyed teamwork and the social aspects of working either on site or in a large design office. But this loss is small compared with the job satisfaction which comes from playing a key role in the assessment of projects.

Everything has changed in the 42 years I have been involved with road design. Computer analysis has replaced the use of slide rules and calculation sheets for structural design; CAD has replaced the hand-drawn drafts which were beautifully traced by the formidable ladies from the tracing pool; road alignment is computer defined using a three-dimensional mathematical model rather than by arcs, straights and transitions drawn on a piece of paper; setting out is done by GPS (global positioning system) and EDM (electronic distance measurement) instead of the methods that Brigadier Bomford taught me.

Design methods and tools have improved dramatically over the period, alongside the more refined methods of economic and environmental assessment. Meanwhile, the network is almost complete and road-building remains out of fashion. Now that the profession has perfected its skills, its task may be almost done.

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