Traffic Engineering Design
In the introduction to his book Gordon Wells quoted the Institution of Civil Engineers1 for his definition of traffic engineering, that is:
That part of engineering which deals with traffic planning and design of roads, of
frontage development and of parking facilities and with the control of traffic to
provide safe, convenient and economic movement of vehicles and pedestrians.
This definition remains valid today but there has clearly been a change in the emphasis in the
role of the traffic engineer in the time since this book was first produced. In the 1970s the car was
seen as the future and the focus was very much ‘predict and provide’. Traffic engineers were
tasked with increasing the capacity of the highway system to accommodate what seemed and endless
growth in motor traffic, often at the expense of other road users. Road capacity improvements
were often achieved at the expense of pedestrian freedom of movement, pushing pedestrians to
bridges and underpasses so that the surface could be given over to the car. However, it is now generally,
but by no means universally recognised that we will never be able to accommodate unconstrained
travel demand by car and so increasingly traffic engineering has become focused on
sharing space and ensuring that more sustainable forms of transport such as walking and cycling
are adequately catered for.
This change has been in response to changes in both society’s expectations and concerns about
traffic and the impact of traffic on the wider environment. There has also been a pragmatic change
forced on traffic engineers as traffic growth has continued unabated and so the engineer has been
forced to fit more traffic onto a finite highways system.
Since 1970, road travel in the UK has increased by about 75% and, although many new roads
have been built, these have tended to be inter-urban or bypass roads, rather than new roads in
urban areas. Thus, particularly in urban areas, the traffic engineer’s role is, increasingly, to
improve the efficiency of an existing system rather than to build new higher capacity roads.