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Alan Brett

UK & Europe

Alan is a technical director at Atkins in the UK, responsible for major transport planning projects, including multi-modal transport studies, transport modelling and appraisal, traffic and revenue forecasting for major transport infrastructure projects and expert witness at public inquiries. He is a founding member and director of BRTuk, the professional body established to provide a knowledge exchange for the development of Bus Rapid Transit systems in the UK.

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In my experience transport modelling techniques have changed little over the last 30 years. Whilst advances in computing have enabled us to run increasingly large and complex models, the underlying processes have changed little from the models I was building in the 1980s.  A key factor in this lack of change has been the continuing use of interview based data to identify why, where, when and how people are travelling. 

New technology is now presenting us with exciting new data sources, in particular satnavs and mobile phones, which have totally different, in some ways opposite, characteristics from traditional data. For example, mobile phone data explains where and when a large proportion (typically 40%) of the population are travelling on a 24/7/365 basis, but not why or how.  Conversely, interview data only represents a tiny proportion of the population for a ‘snapshot’ in time, but does explain why and how they are travelling.

Understandably, and correctly given current guidance and best practice, the focus at present for use of mobile phone data is a series of complex and assumption based processes in order to manipulate the data into the traditional form used in transport models.  
New technology isn’t just affecting the data available to us, it is providing a range of new technological solutions to transport needs that have the potential to transform the use and provision of transport systems.  

Looking to the future I think this raises some challenging questions:

  • Are we making best of use new data sources by adapting these to suit traditional transport modelling techniques?  
  • Should we recognise that new data sources and new technological solutions may be incompatible with traditional modelling?  
  • Do the needs of new transport solutions and the advent of new data provide the catalyst for us to develop entirely new methods of transport modelling?

An analogy would be the introduction of concrete in bridge construction, where early works such as Glenfinnan Viaduct (of Harry Potter fame!) were built using concrete in the same way as masonry would have been used.  Subsequently, techniques to take advantage of the characteristics of concrete led to new approaches in civil engineering design and construction. 

I believe that the move towards active technological solutions for transport (intelligent mobility), together with the advent of new data sources such as mobile phone data, challenges the continuing use of traditional modelling approaches.  So let’s have a ‘Glenfinnan’ moment with a radical rethink as to what we will really need from our transport models in the future and how we can make best of new data sources to fill this need.  

UK & Europe,

There is much debate as to the ability of bus based rapid transit systems (BRT) to attract car users, particularly in comparison with rail based systems. Most of this discussion is based on assertion rather than evidence – but whilst limited, that evidence which is available shows a consistent picture.

Direct comparison of the attractiveness of bus and rail based systems is generally not possible, as bus systems are rarely delivered with the range of features, in particular segregation, provided for rail systems. Research by Ben-Akiva in the US, reported in 2002, examined bus and rail systems using preference research techniques to remove the effects of differing characteristics and concluded that ‘there is no evident preference for rail travel over bus when quantifiable service characteristics such as travel time and cost are equal’. This conclusion is reflected in the ‘Affordable Mass Transit Guidance’ published by the Commission for Integrated Transport in 2005, which considered evidence from LRT and BRT experience in the UK together with the Ben-Akiva research. The guidance advises that bus and rail based alternatives ‘where service levels are similar’ should be tested with the assumption that modal attraction is the same for both modes.

Thus a key difficulty in understanding the relative attractiveness of BRT and LRT (light rail transit systems) arises from the lack of systems with equivalent characteristics and contexts. There is one very useful case in Nantes in northern France which does enable direct comparison between BRT and LRT. Nantes has LRT operating on three corridors, but the patronage levels on a fourth corridor did not justify the cost of LRT and BRT was provided instead. Importantly, the BRT was designed to replicate the service characteristics provided in the LRT-served corridors, with similar speeds, frequencies and stop patterns and support by a similar level of quality attributes. Patronage research by the municipal operator showed that the proportion of BRT passengers who were former car users was the same as in the equivalent LRT corridors in Nantes. Subsequently more detailed user research has been undertaken in Nantes and this has shown that there is a slight preference for the BRT services over the LRT, due to a higher comfort rating for BRT, thought due to higher seat provision.

Cambridgeshire Guided Busway
Cambridgeshire Guided Busway connects Cambridge, Huntingdon and St Ives in the English county of Cambridgeshire. It is the longest guided busway in the world, overtaking the O-Bahn Busway in Adelaide, South Australia. Source: Wikipedia

What of experience in the UK? There are relatively few BRT systems in the UK and only one of these, the Cambridgeshire Guided Busway, has been the subject of detailed user research. The Busway opened in 2011, with ridership quickly exceeding the levels forecast for the early years of operation. User surveys were conducted in 2012 in order to better understand the characteristics of the Busway users. The surveys showed that more than 60% of Busway users had a car available for their journey and more than 30% had previously travelled by car and had thus changed mode. Interestingly, frequency of use of the Busway increased with income, with the most frequent users being those with incomes of more then £40k.

So the evidence, whilst limited, is both clear and consistent, where system characteristics are equivalent BRT and LRT will provide similar levels of attraction of car users. The challenge for BRT is to understand the key characteristics that drive patronage and modal attraction and ensure that these are embedded in BRT system design and delivery.

Finally, on a related note, you may be interested to read an associated article written by a colleague of mine – Arafat Ahmad – about the Lahore Metrobus project.

UK & Europe,