This evidence review found a large literature demonstrating that the co-benefits of climate change mitigation action in the transport sector could be substantial. In determining policy, consideration needs to be given to the scale of carbon reduction offered relative to the potential for additional benefits.
Significant research gaps under the shift, reduce and improve framework are detailed below.
Shift to more sustainable modes
- Where co-benefits are established, i.e. with regard to the physical activity associated with active travel, there is need to understand how these benefits can be socially and equitably distributed. There are opportunities here to build on existing Scottish research to better understand how harder to reach groups can be accessed, this includes real world practice and engagement with users.
- The full extent of these health benefits in the Scottish context needs to be better understood. For example, capturing impacts as they relate to years of life lost and years of life living with a disability. Here, links with the proposed updates to WebTAG guidance could be considered.
- Synthesis of existing evidence on the potential for car vehicle kilometre reduction to inform the potential for congestion, noise and air pollutant reduction is necessary. The outcomes of this synthesis can be used to better understand research gaps and identify further data collection requirements.
- The wider implications of modal shift from plane to train currently receives limited consideration in the literature. Drawing from the wider evidence relating to the use and value of time, working time availability on trains may be of benefit and warrants further investigation. The broader literature suggests the potential for there to be induced travel (e.g, due to increased comfort) and further research is required here.
Reduce the need to travel
- The role and extent to which demand management can facilitate take up of walk, cycle and public transport modes could be considered further, with options in the Scottish context evaluated alongside modal shift interventions. This may be particularly relevant to understand the steps required to lock in modal shift benefits, preventing erosion through induced traffic.
- A more detailed understanding of teleworking opportunities and means to overcome barriers especially in the Scottish rural context is required.
Improve transport efficiencies
- For lower carbon vehicles, where there is an indication of benefits e.g. with regard to air quality, the required uptake, including spatial distribution, of these vehicles (to achieve the benefits) needs to be fully understood in the Scottish context. This could for example result in their introduction in vehicles which are in higher use - e.g. taxis or fleet vehicles or in more socially disadvantaged areas (where there tend to be higher levels of air quality pollution).
- Understand the role that car clubs could play in facilitating access to newer technologies to a broader range of socio-economic groups than private ownership would allow.
- For network efficiencies, further consideration of the equalities aspects is potentially required.
Email: Debbie Sagar