The purpose of this literature review is to assess best practice in active travel, covering what works in terms of having the greatest impact on improving rates of walking and cycling. The resulting review will highlight what has been found to work, and what has not, as well as case studies of successful interventions in order to create a framework for success. In addition, it will outline the range of economic, health and environmental benefits that are associated with active travel.
There is a growing body of international grey and academic literature on both best practice and the associated benefits of active travel. In many instances the evidence lacks the necessary robustness to definitively say what the quantifiable result of infrastructural and behavioural interventions would be on a larger scale. Similarly, the majority of the evidence concerning the benefits of active travel is based on case-studies, limiting cross-comparison and generalisability due to the variation in methodology and data collected. As a result, while there is a consensus on the benefits associated with active travel, the literature generally refrains from quantifying them.
Despite these limitations, the direction of causality is clear in terms of both infrastructural and behavioural interventions, and this report focuses on the actions associated with success and the benefits that can accrue as a result of active travel, rather than on quantifying them.
The literature noted many different interventions that were successful in increasing walking and cycling to some extent. The interventions considered most impactful are outlined below.
- Success in walking interventions came predominantly from behavioural interventions, with programmes targeting patients’ health or poor health outcomes showing significant improvement through increases in walking levels. Infrastructure was only seen as improving safety, with mixed land use and density being more important factors to induce walking for transport.
- Access to public transport was seen as a strong determinant of walking for transport. Residents with 30 or more bus stops in a 1.6km radius of their homes were twice as likely to walk for transport as those who had 0-14 bus stops, and having a train station within a 1.6km radius increasing the odds of walking by 50%
- It was heavily emphasised in the literature that the best point to target behavioural interventions to achieve modal shift was during ‘trigger points’ in people’s lives. Examples being: periods of transition in employment or education; entering parenthood, especially motherhood; people recovering from ill health; people with increased leisure time; and people moving home.
- Bike sharing improved cycling levels in cities with low levels of cycling modal share, with density of docking stations being important for the programme to achieve success. Although it has been noted that the majority of the shift to bike share comes from public transport and walking.
- Cycle-lanes that form a continuous network are a necessary condition for encouraging modal shift to cycling. However, provision of infrastructure is insufficient on its own, and has to linked with behavioural or policy interventions to make cycling more attractive in order to achieve a modal shift. Once modal shift has been achieved the cycle lanes are used heavily by cyclists, further reinforcing their status as necessary for modal shift.
- One of the key factors in modal shift was the attractiveness of cycling as compared to motor vehicles. Higher levels of motor vehicle congestion and less parking availability makes cycling more attractive. This ties in with another finding that indicates that directness and journey time are important in achieving modal shift.
- Several workplace interventions were successful in encouraging active travel uptake. These include personal travel plans timed with trigger points, inter office active travel competitions and decreased parking availability.
- Interviews with experts who had led successful modal shifts in UK and international cities noted several key components of success. Long term projects, of 5-10 years, where considered essential in driving sustained modal shift, with the projects focussed on building a network of cycle lanes where funding allowed, or on implementing a range of behavioural measures to create a cycling culture where funding was harder to obtain. They also noted that the mix of revenue to capital for projects was not especially important, but stated that any project must always come with some revenue spend.
- Some interventions can work but often fail to achieve their goals. Off-road cycle paths is one such intervention that in some instances can work but often fails to achieve modal shift due to low awareness and being a less direct route than using the main road.
- Similarly, there are interventions which have been found to have a negative impact on particular groups. Evidence on shared spaces interventions has shown how the design choice used can be detrimental and cause serious issues for people with visual impairments. In one case, this led to visually impaired people stating that they would no longer be able to use the area independently.
Whilst these interventions are noted as having positive effects, the quantifiable effect of the interventions is lacking. As such, the responses from expert interviewees in the literature provide some of the best notes on ways to improve an intervention’s chance of success.
There are a selection of successful projects which are useful examples to emulate. In particular the Cycling Cities and Towns project in England, a continuation of the Cycling Demonstration Towns , are good examples of success in Britain. Between 2007-2011 the 12 intervention areas saw an average increase in cycling of around 20%. This was built off the back of the Cycling Demonstration Towns and Sustainable Travel Towns that noted that longer term projects with established teams and plans gave significant results.
Other examples of success are the Sustainable Travel Towns in England and the Smarter Choices Smarter Places in Scotland. Both programmes worked to improve bus services as well as advertising campaigns and personal travel plans to improve active travel. Both programmes saw a significant shift away from cars towards walking and bus use, with the Sustainable Travel Towns in England also seeing an increase in cycling. The results suggest that while behavioural interventions can increase walking trips, access to a good bus network is key to allow walking as a means of travel for longer journeys.
What is the recommended path to success?
Long term projects
Long term projects are considered the most successful, with a recommended minimum of five years but an optimal time frame placed at 10 years. Stop-start funding was noted as being ineffective in achieving modal share both because of the incomplete infrastructure and because of the short term funding resulting in some longer term revenue projects not being pursued.
Dedicated teams for a project are considered best practice. Evidence from the Sustainable Travel Towns suggests that teams can take six months to a year to recruit and train in advance of a project, further reinforcing the need for a long term project. These teams are best placed to understand the particular local challenges and come up with more appropriate local solutions and intervention packages.
Focussing on strong citizen participation
Focussing on areas that have strong citizen participation and local authority support, along with well-prepared policies, appears to be the most successful. This indicates that project funding should go to areas where there is a desire to see long term difference and would support a well-planned project, further reinforcing the need for longer term projects.
Revenue spend successful when coupled with quality improvements
Revenue spend is most successful when coupled with improvements in quality, although this could include newly created facilities rather than simply improving on what is available. This is particularly apparent in Doncaster where failure to improve the bus service due to the issues surrounding its two providers severely hampered the drive for sustainable travel compared to other peer cities. It is also noted that when there is insufficient budget to create a comprehensive network, revenue spending is a good policy to create a culture and attitude ready for cycling when the funding is available.
Making motor transport less attractive needed for modal shift.
A major point in the literature is that while quality improvements and infrastructure are necessary conditions for modal shift, they are not sufficient to induce the modal shift due to the availability of cars. Instead that has to come from other sources with one particularly noted area being the attractiveness of cars. If motor transport is less attractive, modal shift happens. This can be achieved by increasing parking tariffs, reducing availability of free workplace parking, and extending the area of paid on-street parking, thereby reducing the availability of parking but not alleviating congestion.
Value of time
The value of time is an important consideration, with evidence showing that active travel and bus travel needs to be sufficiently fast compared to private motorised vehicles to encourage modal shift.
Ensuring that cycle lanes have the minimal interruptions
Ensuring that cycle lanes have the minimal interruptions makes cycling more attractive, with less stops shown to lead to a higher cycling share. This in combination with improving the perception of cycling both in terms of quality and safety (regardless of the validity of that perception) helps increase modal share.
Successful active travel policy
Successful active travel policy is heavily dependent on external factors such as demographics, land use mix, population density and topography amongst other things. This suggests that there is a justification for different intervention mixes in different cities to overcome these factors.
The range of potential policy packages is very broad
The range of potential policy packages is very broad, but a typical package could include: the creation of local bicycle statistics/metrics; marketing to improve co-existence of pedestrians and cyclists; route promotion marketing; innovative parking solutions; healthy cycling and walking campaigns; cycle website improvements; and safety strategy improvement. The literature also recommends supportive land use planning as well as restrictions on car use.
Several papers outline what the general spend in towns is to achieve cycling uptake. The Sustainable Travel Towns project had an average spend of £19-£29 per head of population per year over a five year period (Urban Transport, 2011), although these funds also include walking and bus spend. A similar project in Scotland (Transport Scotland, 2013) spent between £5-£18 per person per year over three years which included walking and bus spending. The Cycling Demonstration Towns (DfT, 2009) spent around £10 per person per year for the first five years, where other English local authorities were spending roughly £1 per head. The follow up to Cycling Demonstration Towns including the Cycling Cities and Towns projects (Sustrans, 2017), was found to cost on average £14 per head of population per year for the five years prior to the report.
Finally, Sustrans estimates that to achieve a doubling of cycling journeys in England there would have to be a spend of roughly £17 per person per year over a 10 year period (2016). The evidence suggest that a spend per person in the treatment areas ranging between £10-£30 per annum over 5-10 years, would be reasonable and in keeping with past successful projects. However, due to the nature of the data it would be unwise to extrapolate a certain spend with a certain effect.
What are the associated benefits?
The majority of the benefits associated with active travel are as a result of improved health outcomes. Provided that it is sufficiently frequent and intensive, physical activity through active travel is associated with a reduction in all-cause mortality and in the incidence or severity of a number of health conditions including: stroke, obesity, type II diabetes, cardiovascular disease, colon and breast cancer, hypertension, depression and anxiety. In older adults it is further associated with improved levels of functional ability and reduced incidence of dementia.
Health benefits are subject to a dose-response relationship such that larger risk-reduction is accrued at higher levels of physical activity, with a capped maximum risk-reduction generally placed at five years of consistently high levels of physical activity. There is a consensus that a mode shift to active travel results in substantial health benefits at an individual level. This is the case irrespective of baseline activity levels or geographical context, and outweighs any increased risk in terms of pollution exposure or road safety. Men, older adults (generally 45 years and greater) and members of ethnic minorities are generally found to benefit more from active travel than the rest of the general population.
Additionally, active travel can result in substantial savings at an individual level when compared to the use of motorised vehicles or public transport, especially for short journeys. Active travel modes are the lowest producers of emissions and air pollution per passenger-km.
Despite the clear health and environmental benefits of active travel at an individual level, it is important to note that their impact on a societal level are minimal unless a consequential mode shift can be achieved. Should the number of active travellers substantially increase, a number of economic benefits could emerge such as health-care savings, retail spending, tourism, increased productivity and reduced absenteeism.
The evidence indicates that high quality, joined-up infrastructure and behavioural interventions at trigger points in people’s lives are the most effective measures to encourage an uptake in active travel. However, the quantitative effect of these interventions is much less clear, in part due to the effect of external factors such as local weather, topography and population density. It is often noted in the literature that infrastructure is a necessary but insufficient condition on its own for a modal shift to active travel. Other factors such as the attractiveness of motor transport, environmental factors, and linked behavioural interventions all play an important part in the success of a project. In particular with walking, mixed land use and density play a more important role in determining modal share.
One of the most prevalent issues in encouraging active travel is journey time compared to motor transport. Individuals are more likely to switch to active travel modes, including mixed modes with public transport, when their journey time is reduced compared to making the trip using private motorised vehicles.
Off-road cycle paths do not appear to bring an improvement in cycling modal share, and are noted as not being attractive to female cyclists. Additionally, shared spaces can have benefits for pedestrians but with poor implementation they can adversely impact others.
There are substantial gaps in the literature, notably on the effect of active travel infrastructure on people with disabilities. In addition, there is a lack of evidence on the optimal mix of infrastructure and behavioural interventions, with some of this likely due to the highly context-dependent nature of successful interventions.
Given the lack of quantifiable data, the responses by expert interviewees in the literature provide some of the best notes on ways to improve an intervention’s chance of success. They note that the most successful projects are those with a minimum term of five years, with stop-start funding being associated with poor results. They also note that while the size of the revenue spend is not as important, it is imperative that all capital projects come with at least some revenue spend. Finally they note that cycle infrastructure should be built as a comprehensive and continuous network and not as discrete and disconnected routes. If it is not possible to build a comprehensive network it would be better to invest the money in revenue spend to create a groundswell of support for cycling so that when the infrastructure is finally built the uptake will be a lot quicker.