Background Reducing car use and encouraging alternative modes of transportation is vital for planetary and public health. Policy interventions by local governments have potential to be effective, but policy change is needed before evaluations can be conducted, underscoring the importance of understanding policy processes. Multi-component interventions with both positive (ie, carrot) and negative (ie, stick) strategies have demonstrated effectiveness, but ‘stick’ strategies often face challenges in public and political acceptability. Understanding of the processes leading to population health policy development and implementation is currently limited. This study aims to understand the key arguments surrounding citywide transport proposals to reduce congestion and promote sustainable travel in Cambridge, UK.

Methods The Making Connections 2 transport proposal sought to reduce congestion and improve air pollution by transforming the bus network, investing in walking and cycling infrastructure and implementing a road user charge. Following a public consultation, proposals were abandoned due to a lack of political consensus. Using a qualitative design, we analysed data generated during the public consultation between October and December 2022. Written consultation responses, representing views of organisations influenced by the policy, were downloaded from the consultation website. We analysed data using thematic analysis in NVivo 12 to identify the key arguments surrounding the transport proposals.

Results We included118 written consultation responses from organisations including civil society groups (20%); local governments (15%) and education (11%). Other sectors represented (<10% each) were health and social care, charities, leisure, property development, transport, retail, science and technology and logistics. We identified six key themes ‘Support for reducing congestion and air pollution’, ‘Concern for the effect on vulnerable populations’, ‘Protection of healthcare resources’, ‘Identification of unintended consequences’ ‘Economic vitality and growth’ and ‘Distrust in authority’. While there was overall support for reducing congestion and improving air pollution, concerns primarily revolved around the design aspects of the road user charge, such as boundary definition, operating hours and administrative complexities associated with exemptions.

Conclusion Our analysis of public consultation responses identified complex and nuanced arguments with broad support for the overarching aims, countered by specific concerns regarding the design of the road user charge and fairness. Similar proposals have been made, and subsequently abandoned in other cities in the UK (e.g. Edinburgh). If we are to fully understand the public health and policy challenges, we require a more detailed account of the specific mechanisms by which actors influence both the formation and implementation of policy.