Connect with Tim PharoahConnect with Tim Pharoah
South Birmingham Environmental Traffic Management Study (SOBETMA)

South Birmingham Environmental Traffic Management Study (SOBETMA)

This ground-breaking study (1992) ushered in a new approach to management of urban road networks. The concepts have since found their way into guidance, including Manual for Streets and Manual for Streets 2.

The study aimed to find ways of reconciling conflicts on the network between traffic and other neighbourhood activities, following the abandonment of earlier plans for new and widened roads. It was also aimed at healing a rift between the strategic intentions of the city council and the opinions and feelings of local populations in south Birmingham. The study area was unusually large, containing a population of around 250,000.

A new approach to street classification

The classification of streets was traditionally done according to vehicle traffic importance. SOBETMA uses a classification based on other functions of the street as well as vehicle movement, such as retailing, loading, parking, sojourn, recreation.

The adopted classification is also radical in that the main road (traffic priority) network is discontinuous. It is interrupted by "mixed priority" lengths of road, mainly through shopping areas, but also near schools and other environmentally sensitive locations. This acknowledges that traffic can be managed in different ways at different sections along a single route. Drivers are not prevented from going through, but their speed, and the degree of priority afforded to them can change according to the life on either side of the route.

Design for "mixed priority" streets

The report suggests ways of "re-profiling" mixed activity areas, to provide more space for pedestrians and bus priority. Examples are "2 lanes plus turns" and "almost 4 lanes" designs. Techniques for improving mixed activity main streets draw on experience from the near continent (Netherlands and Germany). The theories and concepts involved are elaborated in technical appendices.

The PTRC article (see pdf) describes the context of the SOBETMA within the wider South Birmingham Study, and summarises the key points.

[Note: the banner image above is an example of how graphics often miss the point. It depicts a bus lay-by, but SOBETMA promotes bus priority and bus lay-bys are devices to give priority to other traffic!]

LocationBirmingham England
Client(s)Birmingham City Council
Team(s)Tim Pharoah with MVA


Traffic management, environmental improvement, economic regeneration, traffic calming, street design, public realm, Birmingham, South Birmingham Study, SOBETMA