Safe cycling with permanent vision impairments?
“Visually impaired people shouldn’t ride a bicycle.” This is a common first reaction when I just start to explain my research project.
In the Netherlands, cycling is very important. Cycling enables people to be mobile and independent, and to participate in social life. Its importance is shown by the number of bicycles per Dutch citizen. With 1.3 bicycle per inhabitant (Stichting BOVAG-RAI Mobiliteit, 2018) the Netherlands is probably the only country with more bicycles than citizens! Cycling is not only important for people with normal vision, but can also be important for people with permanent vision impairments (i.e. low vision), especially for those who are unable to drive a car.
People with low vision are allowed to cycle, as long as they do not endanger themselves or others (Wegenverkeerswet, 1994). In contrast to driving, there are no minimal vision requirements for cycling. However, whether independent cycling with low vision is still a safe thing to do can be difficult to determine. Dutch vision rehabilitation centres provide advice and cycling training for visually impaired people. The mobility instructors aim to optimise the client’s independent mobility, whilst at the same time protecting general safety. Mobility instructors tend to be conservative in their cycling advice because the knowledge on this topic is scarce. Consequently, there may be many people with low vision who are unnecessarily discouraged from cycling, which may in turn negatively influence their social participation and physical fitness.
There are, in fact, many people who do cycle at a daily basis while they have serious limitations in seeing details or miss a substantial part of their visual field (Jelijs, Heutink, De Waard, Brookhuis & Melis-Dankers, 2019). Somehow they seem to compensate for their limitations. Within the project ‘Safe Cycling’ we aim to understand (1) which circumstances complicate cycling with low vision and (2) how the visually impaired cyclists compensate for these circumstances.
To achieve these goals, I consulted an expert group on cycling and low vision. I asked them about the most important factors related to cycling with low vision (in a so-called Delphi study). They indicated that self-confidence belongs to the key personal circumstances. Three key environmental circumstances they mentioned were (Jelijs, Heutink, De Waard, Brookhuis & Melis-Dankers, 2018):
1. the traffic situation (e.g. complexity),
2. characteristics of the infrastructure (e.g. road surface quality),
3. weather and light conditions (e.g. sunlight brightness).
Many visually impaired cyclists overcome some of the environment-related difficulties by selecting a route and departure time that fit their vision limitations. However, risks particularly arise when the cyclist needs to make real-time decisions. In contrast to route selection or departure time, the decisions to steer, brake, and give way are primarily based on visual input and cannot be made ahead of the ride. We hypothesise that visually impaired cyclists compensate for their vision impairments by creating a “buffer-zone”, thereby increasing the time they have to process visual information and respond accurately. For example, someone could cycle at a lower speed, which decreases the braking distance and creates time for them to respond. Similarly, cycling more towards the centre of the cycle lane (i.e. further away from the side) could make it less likely to veer off the road and hit the kerb or end up in the verge.
Is it safe for people with permanent vision impairments to ride a bicycle? As shown in this blog post, we need to look beyond the limitations of people with low vision. Many visually impaired people are able to cycle independently despite their limitations. Their bike riding safety depends on whether they are sufficiently capable of taking their limitations into consideration when making cycling-related decisions.
Jelijs, B., Heutink, J., de Waard, D., Brookhuis, K. A., & Melis-Dankers, B. J. M. (2019). Key factors for the bicycle use of visually impaired people: a Delphi study. Disability and Rehabilitation, 41, 2758–2765. DOI: 10.1080/09638288.2018.1476921
Jelijs, B., Heutink, J., de Waard, D., Brookhuis, K. A., & Melis-Dankers, B. J. M. (2019). Cycling difficulties of visually impaired people. British Journal of Visual Impairment, 37, 124-139. DOI: 10.1177/0264619619830443
Stichting BOVAG-RAI Mobiliteit (2018). Mobiliteit in Cijfers: Tweewielers 2018 – 2019. Retrieved from: https://bovagrai.info/tweewieler/2018/media/Mobiliteit-in-Cijfers-Tweewielers-2018-voor-download.pdf
Wegenverkeerswet 1994 artikel 5 [article 5 of Dutch road traffic act of 1994].