How to make more cycling good for road safety?

https://doi.org/10.1016/j.aap.2010.11.010Get rights and content

Abstract

This paper discusses the current level of the road safety problems of cycling and cyclists, why cyclists run relatively high risks, and why cyclists may be considered as ‘vulnerable road users’. This paper is based on peer-reviewed research which give some idea how to reduce the number of cyclist casualties. However, this research is rather limited and the results cannot (easily) be transferred from one setting or country to another: generalization of results should only be done with the utmost care, if it is to be done at all. Interventions to reduce cyclist casualties worldwide seem to be of an incidental nature; that is to say, they are implemented in a rather isolated way. In a Safe System approach, such as the Dutch Sustainable Safety vision, the inherent risks of traffic are dealt with in a systematic, proactive way. We illustrate how this approach is especially effective for vulnerable road users, such as cyclists. Finally, the paper addresses the question of whether it is possible to make more cycling good for road safety. We conclude that when the number of cyclists increases, the number of fatalities may increase, but will not necessarily do so, and the outcome is dependent on specific conditions. There is strong evidence that well-designed bicycle facilities—physically separated networks—reduce risks for cyclists, and therefore have an impact on the net safety result, for example if car-kilometres are substituted by bicycle kilometres. Policies to support cycling should incorporate these findings in order to make more cycling good for road safety.

Research highlights

Cyclists run a relatively high risk because the human body is fragile and lacks protection in a crash. ▶ Separation of transport modes and reducing speed of motorized vehicles improve cyclist safety. ▶ Promoting bicycling should be accompanied by planning and design of safe bicycle facilities. ▶ Knowledge from research cannot easily be generalized because local conditions differ considerably.

Introduction

If we compare bicycle use among different countries there are enormous differences: from near absence to widespread use in countries such as the Netherlands. The amount of cycling is often partly determined by a country's geography (hills and mountains) and its climate (temperatures, snowfall). There are countries where cycling is practiced for recreation. And, finally, there are countries in which cycling is a substantial part of everyday life. Although cycling activities also take place in rural areas, the majority of the bicycle kilometres in such countries are travelled in towns and cities, and over relatively short distances.

Differences in bicycle use can be observed in bicycle culture, purpose of bicycle use, the position of the cyclist in traffic, and the measures that have been taken to make cycling safer.

Many different arguments can be used to promote cycling. An important distinction that must be made is whether cycling is recreational, or whether it is a means of transport to travel from A to B. Some of the arguments used are: cycling is healthy, cycling is good for the environment if it takes the place of motorized journeys, cycling makes a contribution to the prevention of congestion because cyclists take up less space than (parked) cars, and cycling is cheaper than travel by passenger car or public transport. Compared to walking, cycling increases the distances that can be covered and in developing countries it can contribute to the economic development and aid the fight against poverty. Nowadays, more and more governments, cities and villages, communities encourage their citizens to cycle.

One important objection can be made against promoting cycling: it is rather dangerous. As a direct consequence of the laws of (bio)mechanics and the fragility of the human body cyclists are vulnerable in traffic. Cyclists fall easily and can sustain serious injury. In crashes, other than sometimes by a bicycle helmet, a cyclist is unprotected. Brain damage is a serious and frequent injury, often sustained by young people in particular. When a cyclist is injured in a crash with a motorized vehicle travelling at high speed, kinetic energy is processed. Furthermore, a cyclist can lose control of the bicycle, take a fall, and be injured, especially if a cyclist is inexperienced or when obstacles play a role. Often cyclists fail to obey the traffic rules and show unexpected behaviour in the eyes of other road users. The consequence is that cyclists have a relatively high crash rate compared to that of pedestrians and particularly that of drivers. Because cycling is relatively risky we have to ask ourselves whether or not it will increase injuries and fatalities if a government is successful and more people do indeed use a bicycle.

The use of a bicycle as a transport mode differs tremendously among countries: from practically non-existing up to almost 30% of all trips being made by bicycle in, for example, the Netherlands. The number of bicycle kilometres travelled per inhabitant varies as can be seen in Fig. 1.

Bicycle use is increasing (slightly) in some European countries, more specifically in cities. Many countries experienced a steep decrease in bicycling after the Second World War in conjunction with an increase in motorization (FHWA, 2010). In other countries, such as China, the cycling tradition has been taken over by motorized vehicles. Bicycle use is also determined by the geography of a country and its climate. A bicycle can be used for recreation or be substantial part of the modal split. Sometimes cycling is restricted to certain age groups (young and old), to lower socio-economic classes, and in many countries worldwide cycling is a male activity. There is such a variety in bicycle traffic that to sketch a mean picture would obscure reality. A fact or finding from one country can only be transferred to other countries with great caution, if this should be done at all.

The most common problem for cyclists worldwide is that our modern traffic system is designed largely from a car-user perspective, which results in a lack of coherent planning of route networks for cyclists (ETSC, 1999). Nor does the system take the main characteristics of cyclists into account: a cyclist is vulnerable (in a crash), flexible (in behaviour), instable (may fall off the bike), inconspicuous (difficult to see), has differing abilities (due to a wide range of the population), is conscious of effort (i.e., highly motivated to minimize energy expenditure), and sometimes seen as intruders in the traffic system, rather than as an integral part. These key problems also occur in combination.

Different countries worldwide indicate that cyclists have a relatively high crash rate compared to car drivers and pedestrians. As will be discussed in Section 2.1, we know that bicycle crashes suffer from underreporting, especially when non-fatal injury is concerned.

In general, we find higher crash rates for cyclists than for drivers. A difference of a factor of more than 10 was found in a relatively old study in Europe (PROMISING, 2001). More recent developments in the Netherlands indicate that in a 20 year period (1988–2009) the number of cyclist fatalities was halved and that of car drivers and passengers reduced by 55%. At the same time the number of kilometres travelled by cyclists increased by about 30% and that of cars, an important crash opponent, increased by almost 80%. This means that risks of cyclists (per kilometres travelled) decreased less than risks of car occupants during this period.

It is important to understand that when comparing transport modes risk factors obscure age effects. Because especially the young and the elderly have relatively high crash rates (see also Table 2), the mean crash rate for a country is strongly influenced by the share of these high risk groups in the total number of fatalities.

Fig. 2 shows the relation between fatality rates and bicycle usage for a number of European countries (as referred to by van Hout, 2007). The graph depicts the relationship between the distances travelled by bicycle (kilometres travelled per person per year) in several European countries with the fatality rate (number of fatalities per kilometre travelled) in those countries. A regression line can be drawn which suggests that countries with a lot of bicycle traffic have a relatively low fatality rate (e.g. the Netherlands and Denmark) while countries where inhabitants do not cycle much (a dozen of kilometres per inhabitant per year only) face relatively high fatality rates. However, if we compare Portugal, Spain, France and the UK, all counties with less than 100 km travelled per year, we observe a wide variance. We, therefore, apparently need more factors than just the number of kilometres travelled to explain differences in fatality rate. The graph in Fig. 2, however, is very important indeed in scientific literature (Jacobsen, 2003). This intriguing relationship will be discussed in Section 5.

Three different groups of countries can be distinguished according to different levels of bicycle use and fatality rate:

  • Denmark and the Netherlands, in which the distance travelled by bicycle is relatively high and the fatality rate is relatively low.

  • Southern European countries like Portugal and Spain, in which the distance travelled by bicycle is relatively low, but the fatality rate is relatively high.

  • Countries (almost all other) in which the distance travelled by bicycle and number of trips are low, but the fatality rate for cyclists is also low.

However, in the latter group, we can observe major differences; for example, between the UK and Sweden on the one hand, and Austria on the other hand. This illustrates that the distance travelled cannot explain all differences in fatality rates; an interesting observation for further research.

Cycling advocates never tire of stating the great advantages of cycling, especially compared with travelling by car. For example, they refer to the health benefits if cycling results in incorporating exercise into someone's life. Using active transportation modes results in lower obesity prevalence for populations and better cardiovascular health. In their review Pucher et al. (2010) suggest that ‘the combined evidence presented in these studies indicates that the health benefits of bicycling far exceed the health risks from traffic injuries, contradicting the widespread misperception that bicycling is a dangerous activity’. However, In his book ‘Pedaling revolution’ (2009) Mapes states that Pucher ‘.. makes no pretense of being the detached academic’. The sources supporting the claim that cycling is healthy need some scrutiny before it can be accepted. This can be illustrated with a frequently cited conclusion of Bassett et al. (2008) that there is an inverse association between active transportation (walking, biking and public transport/transit use) and obesity rates in the countries studied: the more walking, cycling and public transport use, the lower the obesity rates. However, these authors, and rightly so, do not claim to have established a causal relationship, because they were not able to control for other factors that could influence obesity rates such as other physical activity domains or international differences in ‘energy intake’.

A Dutch study (de Hartog et al., 2010) published findings using results of international literature which were applied to the Netherlands. The study assumes that 500,000 people (ages 18–64) make a transition from driving to bicycling for short trips on a daily basis, and concludes that the beneficial effects of the increased physical activity amount to 3–14 life months gained, which is substantially higher than the potential mortality effect of the increase in inhaled polluted air (0.8–40 days lost) and the increase in traffic crashes (5–9 days lost). Therefore, it concludes that the health benefits of cycling outweigh the health risks. This study, however, excluded high risk groups (cyclists younger than 18 and older than 64) and including theses groups will definitely influence the end result (see also Section 5).

The advantages of cycling are often cited in policy documents promoting cycling all over the world (Dekoster and Schollaert, 1999, CEMT, 2004, Racioppi et al., 2005, Austroads, 2005, USDOT, 2010, WHO, 1999). The supposed advantages are not only related to individual health improvements, but also to less air pollution, less congestion and less noise. Although, these claims are supported by logical assumptions (e.g. bicycle traffic will replace motorized traffic), the reported results are dependent on the conditions under which the change takes place. This limits generalization, and therefore reported results are not universally valid. Designers of strategies to promote cycling should always keep that in mind.

Section snippets

Road safety problem of cycling

The considerable differences among countries do not allow for a meaningful comparison of the well-known crash characteristics as reported in police or hospital reports. Three issues are problematic in drawing conclusions from police reports: underreporting, age distribution, and some fundamentals in the causes of crashes with cyclists in relation to the key problems of this transport mode.

Interventions to reduce risks and severity of bicycle crashes

Good evidence that cycling is relatively hazardous and a growing interest in many parts of the world in promoting cycling raises the question of how to reduce the hazards of cycling and how to minimize the negative consequences of a crash. Our survey of peer-reviewed research indicated that a rather limited amount of research on cyclist safety is available. Before applying solutions, it is important, once again, to make clear that results cannot (easily) be transferred from one setting or

Sustainable Safety: how to reduce cyclist injuries drastically?

Because traditional policies were becoming less effective and less efficient in many highly motorized countries, and because the inherent risks of our road transport problems had not adequately been addressed, the Sustainable Safety vision was developed in the Netherlands (Koornstra et al., 1992, Wegman and Aarts, 2006, Wegman, 2010). The increasingly diffuse character of the road safety problems requires a different approach from that in the past. With the Sustainable Safety vision SWOV

More cycling and its road safety impact

A growing interest in the promotion of cycling by making it more attractive can be observed in highly motorized countries. This is also the case in the plans of many European cities. Signals indicating a move in this direction are also coming from countries like the United States and Australia. Other than the odd exception like Bogota in Peru, such signals are not received from Asian, African and Latin American countries. In contrast, these countries rather have an increase in car use which

Discussion and conclusions

  • 1.

    Cyclists run a relatively high risk of being injured in a road crash. The most common problem for cyclists worldwide is that our modern traffic system is designed largely from a car-user perspective. This results in lack of coherent planning and design for cyclists. Cyclists are vulnerable road users because the human body is fragile and they lack protection in a crash. Their main problems are crashes with motorized vehicles. But also single-vehicle crashes are a significant part of their

References (50)

  • J. Dekoster et al.

    Cycling: The Way Ahead for Towns and Cities

    (1999)
  • Delhomme, P., De Dobbeleer, W., Forward, S., Simoes, A., 2009. Manual for designing, implementing and evaluating road...
  • Derriks, H.M., Mak, P.M., 2007. IRTAD Special Report: Underreporting of Road Traffic Casualties. Ministry of Transport,...
  • Eenink, R., Reurings, M., Elvik, R., Cardoso, J., Wichert, S., Stefan, C., 2007. Accident prediction models and road...
  • R. Elvik et al.

    The Handbook of Road Safety Measures

    (2009)
  • ERSO, 2008a. Pedestrians & Cyclists-Web text of European Road Safety...
  • ERSO, 2008b. Traffic Safety Basic Facts 2007....
  • ETSC

    Safety of Pedestrians and Cyclists in Urban Areas

    (1999)
  • FHWA, 2010. Pedestrian an bicyclist safety and mobility in Europe. Publication No. FHWA-PL-10-010. FHWA/US DOT,...
  • J.J. de Hartog et al.

    Do the Health Benefits of Cycling Outweigh the Risk?

    (2010)
  • K. van Hout

    De risico's van fietsen. Feiten, cijfers en vaststellingen

    (2007)
  • Houtenbos, M., 2008. Expecting the Unexpected: A Study of Interactive Driving Behaviour at Intersections, SWOV,...
  • M. Hudson

    The Bicycle Planning Book

    (1978)
  • P.L. Jacobsen

    Safety in numbers: more walkers and bicyclists, safer walking and bicycling

    Injury Prevention

    (2003)
  • van Kampen, L.T.B., Schoon, C.C., 1999. De veiligheid van vrachtauto's; Een ongevals- en maatregelenanalyse in opdracht...
  • Cited by (0)

    View full text