What will the likely transport impact of a new development be? How many trips is it likely to generate? To work this out, transport planners use TRICS, which is a database of information about the trips generated by past developments.

In the past, TRICs has been used as part of a ‘Predict and Provide’ paradigm, which tends to mean ‘predict how many people will want to drive places, and provide road space for them’.

But this year the consortium behind TRICS released new guidance calling on transport planners to instead ‘Decide and Provide’: decide on the preferred future and provide the means to work towards that. In this guest blog, Lynn Basford of BasfordPowers Ltd, which helped to produce the guidance, explains its implications.

The way that we think about planning for the future is beginning to change and needs to change in light of the UK’s commitment to decarbonising its economy, the Covid-19 pandemic and the digital connectivity that we are now presented with.

As Professor Glenn Lyons recognises in his Foreword to the new guidance released by TRICS this year, “We live our lives within a “Triple Access System” comprised of different and interacting means of being able to access people, jobs, goods, services and opportunities” (the Triple Access System refers to the transport, land-use and telecommunications systems). This needs to be reflected in the way we approach planning for homes and services.

We as land use and transport planners need to embrace the requisite for change and ensure our Local Plans and site specific plans reflect these societal shifts.

The tools that we use in land use and transport planning, and how we use them, need to reflect changing consumer and travel behaviour.

A very well used tool in transport planning is TRICS. TRICS has an ever growing database (some 7,150 transport surveys) of observed trip rates associated with different types and scales of development. It has been a well-used if not default source for supporting the estimation of trip rates associated with new developments. Such measurements have guided the requirements for transport infrastructure and services.

The common use of the ‘Vehicle Only’ TRICS calculation which looks at vehicle and cycle trips can conspire against sustainable development if not used carefully and can lead to the over provision of highway capacity and the potential under provision of walking, cycling and public transport infrastructure and services. This common use (whilst heavily guarded against in the TRICS Best Practice Guidance 2021) equates to a Predict and Provide approach to planning new development.

TRICS does provide multi modal data (walking, cycling and public transport trips), and it is this information along with the analysis of historic trends data that needs to be used to shape developments and plan for sustainable developments.

So how do we stop being insane and planning the same over and over again?

In February 2021 TRICS launched its new Guidance on the Practical Implementation of the Decide and Provide approach. This approach starkly constrasts with the Predict and Provide approach. Its focus is upon deciding on the preferred future and providing the means to work towards that which can accommodate uncertainty. The Decide and Provide approach provides the opportunity to meaningfully prioritise a modal hierarchy giving greater upfront consideration of walking and cycling and asking the three key questions:

• What sort of place are we creating?
• What kind of activities do we need or desire to travel for?
• How will we provide for mobility?

Visioning is central to the Decide and Provide approach. It is essential that transport and land use planners jointly vision development proposals, whether in private sector planning or the public sector development management.

The TRICS new guidance provides us with a detailed methodology for applying the Decide and Provide Approach. For those out there who say that this approach can’t work, TRICS has helpfully provided a set of worked examples including for food retail, discount food retail, large residential, medium residential, residential brown field sites and small residential. Something for everyone!

One of the key take-aways from the guidance is that the TRICS data is showing that trip rates associated with developments are changing and we can change them further by the way we plan new developments.

I believe that we can avoid insanity by embracing this new approach in transport planning which supports the new paradigm of Decide and Provide and we can genuinely get sustainable, adaptive development planning that supports social, economic and travel behaviour change.”

Lynn Basford
Director and Founder of BasfordPowers Ltd