• Question: How complicated can a road really be? Is the design of core infrastructure changing quickly in pratice or is the industry stagnating?

    Asked by William Bradford to Pete on 18 Mar 2015.
    • Photo: Peter Roskilly

      Peter Roskilly answered on 18 Mar 2015:

      Good question.
      The basic design of a road is easy.
      Figure out how to join point A to B, work out the load it’s likely to carry over it’s life time, work out a sufficiently strong cross section then start digging.
      The difficulty comes from the fact that you’ll never have a perfect blank canvas on which to build. Construction of anything is always constrained by the environment into which it’s built and how safe you can make it to use.
      For roads this can be things like the following:
      – Maybe we can’t build a new road. To increase capacity as required you may have no choice but to improve an existing road. That means trying to widen it and make it safer for the increased traffic.
      – Perhaps space is limited. Your new/improved road may have to be squeezed into a tight space. This can make it difficult to design acceptable forward visibility around corners or approaching junctions.
      – Designing a new road these days involves a huge amount of work trying to figure out how to reduce its environmental impact. Are you going to encounter endangered species? Are you cutting off habitats? How can you reduce the visual and auditory impact of your road.
      – On top of that there are a lot of elements that go into road design. As well as the geometry of the road (which is limited by some strict rules) there’s lighting/junctions/safety barriers/bridges/earthworks/utilities/drainage all of which have to have coordinated design. That’s a lot of people trying to work together.
      So yes, the design of roads is straight forward. This is for a reason however. The simpler it is, the easier it is to collaborate and build.

      As to your second part. The design of core infrastructure has not changed much at all. The use of infrastructure hasn’t changed just the need for more and more capacity (hence things like 4/5/6/ lane motorways and high speed rail). The biggest changes are around safety (both in use and construction) and in sustainability.
      The construction industry, particularly Infrastructure construction, is traditionally not very sustainable. The production and use of Cement accounts for a horrifically high proportion of all CO2 emissions. On top of that the main construction materials, like steel and concrete, are not renewable. Because of this there is huge effort in finding new construction materials (recycled plastic bridges or fly ash concrete for example) to make construction more sustainable.
      Change in construction is slow because we don’t like risks. Using something that’s untested can cost lives and testing takes a long time. That said change does happen and will continue to as the way people travel changes and the availability of materials changes.