Health and health inequalities are influenced more by the circumstances in which people live than they are by the provision of health services.

This is reflected in the definition of health contained in the Constitution of the World Health Organisation (WHO), where it is defined as ‘a state of complete physical, mental and social wellbeing and not merely the absence of disease or infirmity'.

From a public health perspective, how people live in a city and how healthy and happy they are depends to a considerable extent on their urban environment, their access to employment, to services, to travel and transport.

It also depends on green spaces and the community around them (often termed wider health determinants).

Thus, travel choices impact on physical activity and on issues such as weight gain and dementia.

In 2007, Bristol City Council agreed that promoting and enabling physical activity in everyday life should be one of the then incoming Director of Public Health's (DPH) top priorities.

By an informal recurrent process involving the strategic director responsible for transport and city planning and the strategic director then responsible for neighbourhoods, green space, culture and leisure, it became evident that for public health to achieve its mission within the city council it had to actively engage with and bring added value to those parts of the council primarily responsible for place shaping, including transport.

With this backdrop, in spring 2008 I took up a unique post in the UK as a public health and transport adviser embedded within the transport planning department.

With an academic background including a doctoral thesis addressing inter-sectoral collaboration on transport planning and health, I spoke the languages of public health and transport planning.

One of my first tasks was to provide input to Bristol's bid – including part of South Gloucestershire – to become the UK's first Cycling City.

The announcement in June 2008 that Bristol was successful occurred just as a Healthy Urban Team (HUT) was established.  The logic behind the HUT was the recognition that the role of the DPH alone is insufficient to address the range of wider health determinants.

By bringing together a spectrum of inputs through specialist ‘experts' and developing the influencing skills at different levels of the system of local government change can be effected.

One of public health's ‘offers' is our expertise in the application of peer-reviewed evidence.

Recognising workloads, I commenced a series of ‘Essential Evidence' summaries taking research wholly apposite to the jobs of transport planners but hidden in academic papers often from non-transport disciplines and written in disciplinary jargon.

So far I have de-jargonised 105 subject papers which each fi t on one page.  A simple
idea, originally for all transport staff within Bristol City Council, but one that now has ‘subscribers' from across the globe.

Robust evidence is important when seeking to influence the Joint Local Transport Plan 3 (JLTP3), developed during 2010 to go live from April 2011 and lasting to 2026.

Here, the value of being embedded came to the fore.  I was invited to be part of the group developing the new plan and was able to input significant public health evidence of effectiveness to support the case for further investment in sustainable transport.

I was also subsequently able to submit formal comments on behalf of the four DPHs in the West of England to the formal consultation.

The JLTP3 is arguably one of the strongest Local Transport Plans evidencing the benefi ts of active travel (including public transport).

The JLTP3 included the ambition for 20mph speed limits across all Bristol residential streets.

This first came from my work looking at the effectiveness of large-scale interventions.  Now, 20mph is now being rolled out across Bristol after successful piloting.

Other significant inputs include providing training for systematic application of the WHO Health Economic Assessment Tool for walking and cycling scheme proposals, commenting on health impacts of major schemes, and input to the Walking Strategy.

Greater emphasis on these and other pathways to improve health were added through Bristol's successful bid to be European Green Capital in 2015.

A key element underpinning all work has been building trust.  This applies to all relationships, from strategic directors to project assistants.

All this work and much more occurred before the return of public health to the council in April.  Looking back, in 2008 the DPH described this stream of work as ‘a journey begun'.

We can take pride that Bristol grasped the sometimes daunting challenges to tackle transport and the built environment so decisively.

We have enjoyed this productive journey due in no small part to the strong collaborative approach of many transport colleagues.

We look forward to the next five years in helping to improve the health and wellbeing of Bristol's population through the reshaping of the transport offers available in order that healthy choices are easy choices.

Dr Adrian Davis is an independent consultant on health and transport, embedded into Bristol City Council's transport department – funded by NHS Bristol