Paper presented at Walk21-VII, “The Next Steps”, The 7th International Conference on Walking and Liveable Communities, October 23-25 2006, Melbourne, Australia www.walk21.com
Emerging road safety philosophies and their significance for safe walking Bruce Corben & Jennifer Oxley Accident Research Centre, Monash University Contact author:
Bruce Corben Accident Research Centre, Building 70, Monash University. Vic. 3088
[email protected]
Abstract The importance attached to walking varies widely throughout modern-day society. In public health terms, walking offers one of the best opportunities to promote good health and personal independence for people from a very wide range of ages and physical abilities. In urban transport terms, walking is an essential component of most public transport trips and also a necessary, albeit minor, part of trips by private car. Walking is inexpensive, highly accessible and imposes no negative impacts on a global environment already labouring under an extreme load from power generation, industry and motorised transport. Pedestrians are the most vulnerable users of the road-transport system, being entirely unprotected in traffic, where vehicles commonly travel at speeds that have a high probability of causing death in a collision with a pedestrian. It is therefore surprising that walking still requires vigorous promotion and advocacy for its needs and many attributes recognised and actually supported through various policies and standards. This paper discusses the emergence of new safety philosophies, such as Sweden’s Vision Zero, The Netherlands’ Sustainable Safety, and more recently Australia’s Safe System, which define a radically new way of thinking about how road-transport systems should “look and operate” in order to prevent, in a sustainable way, the loss of life and long-term health that currently characterises the road-transport system. Australia’s National Road Safety Action Plan has recently embraced this philosophy, providing further impetus for a major shift from traditional ways of designing and operating the road-transport system.
At present, there is a critical gap in knowledge of how to translate the Safe System philosophies into principles for real-world practice that lead ultimately to “safe walking”. The paper presents an overview of the current state-ofknowledge on opportunities to promote safe walking. It describes the extent, nature and trends in pedestrian trauma in Victoria and defines key targets for addressing pedestrian trauma, while catering for increased walking. A particular focus of the paper is on high-pedestrian activity areas and, in particular, road infrastructure and traffic design options for creating pedestrian-friendly, low-risk settings.
Biographies Bruce Corben: Bruce Corben is a Senior Research Fellow at Monash University Accident Research Centre. He has lead many road safety research projects that have focused primarily on road infrastructure safety. Bruce has a Bachelor of Science (Physics), a Master of Engineering Science (Transport) and is nearing the completion of a PhD on creating safe traffic environments for pedestrians. Other research interests include speed and speeding, roadside safety and the development and evaluation of road infrastructure safety programs and countermeasures. His extensive practical experience in traffic safety engineering and traffic management is valuable in translating new research knowledge into practice. Jennifer Oxley: Jennie Oxley is a Senior Research Fellow at Monash University Accident Research Centre and her main area of expertise is vulnerable road user safety and mobility. She manages a range of research projects addressing: the implications of functional performance limitations on child, intoxicated and elderly pedestrian and driver performance and safety; gender effects on travel patterns, driving experience and crash risk; assessing fitness to drive; reduction and cessation of driving; and, countermeasure development.
Emerging road safety philosophies and their significance for safe walking Bruce Corben & Jennifer Oxley Accident Research Centre, Monash University Pedestrians are the most vulnerable users of the road-transport system, being entirely unprotected in traffic, where vehicles commonly travel at speeds that have a high probability of causing death in a collision with a pedestrian. This paper discusses the importance of walking, describes trends in pedestrian trauma in Victoria, and provides an overview of the current state-of-knowledge on opportunities to promote safe walking, with a focus on defining key targets for addressing pedestrian trauma, while catering for increased walking
The benefits of walking Walking offers many opportunities to promote good health, social well-being, personal independence and mobility, while minimising negative environmental consequences (Catford, 2003). It is widely recognised as one of the most inexpensive, accessible and sustainable forms of physical activity available to the majority of the population. Participation in regular physical activity, through walking and other means, can significantly reduce an individual’s risk of developing many diseases, can maintain health and fitness required to function effectively and independently in everyday life, and prevent and reduce the impact of a range of mental and social health issues such as depression, anxiety and isolation (Racioppi, Dora, Krech & von Ehrenstein, 2002; Salmon, Breman, Fotheringham, Ball & Finch, 2000). Furthermore, increasing the uptake of walking as a substitute for motorised forms of transport is associated with environmental and economic benefits, particularly the potential to reduce greenhouse gas emissions. For these reasons walking is heavily promoted by governments world-wide. The Victorian government has acknowledged that the nature of urban development within Melbourne and other large regional centres during recent decades has tended to discourage the adoption of walking as a primary form of travel. The Melbourne 2030 strategy therefore aims to remove barriers to walking (such as presence of heavy and fast moving motor traffic) in order to create an environment that is safe and attractive, and supports all people to adopt walking as a preferred mode of travel (Department of Sustainability and Environment, 2002).
Trends in pedestrian trauma in Victoria Over recent decades, walking as a form of transport has reduced dramatically, as a direct consequence of the increased use of private motor
vehicles. While walking is the primary mode of transport for only a very small proportion of the population (walking was estimated to be the primary mode of travel for only 6% of the Australian population in 1996, Australian Bureau of Statistics, 1998), walking does form an essential component of the daily travel routine for a large proportion of the population, particularly for most public transport trips, but also, albeit minor, parts of trips by private car. Figure 1 shows the number of pedestrian fatalities in Victoria from 1980 to 2004 and shows a gradual reduction in pedestrian trauma. It also shows that the magnitude and timing of reductions in pedestrian trauma observed over the past 20 years in Victoria have been primarily due to the effects of generalised speed enforcement and alcohol restriction programs (Corben & Diamantopoulou, 1996). Following the introduction in late 1989 of speed cameras to Victoria and a concurrent large increase in random breath-testing for the presence of alcohol in drivers and riders, pedestrian deaths fell from an annual average frequency of 150 during the decade of 1980 to 1989 to an average of 80 fatalities per year for the decade 1990 to 1999, inclusive. This represents a 47 percent reduction in the absolute numbers of pedestrian fatalities between the two decades. After the introduction in early 2002 of a strengthened approach to enforcing driver and rider compliance with speed limits, including tighter enforcement tolerances, pedestrian fatalities again fell dramatically, with 41 pedestrian deaths in 2003 and 49 each in 2004 and 2005. This represents a 39 percent reduction compared with the ten-year average of 76 for the period immediately preceding the introduction of the reduced speed enforcement tolerance levels in March-April 2002, a 44 percent reduction compared with the ten-year average of 80 for the decade of the 1990s, and a 69 percent reduction compared with the ten-year average from 1980 to 1989 (Australian Transport Safety Bureau, 2003). P e de s t ria n F a t a lit ie s in V ic t o ria 19 8 0 - 2 0 0 5 200 180 160 140 120 100 80 60 40 20 0 1980
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Figure 1: Long-term trends (1980 to 2005, inclusive) in pedestrian fatalities in Victoria Though deaths per year have fallen since 2000, current levels indicate some 400-500 pedestrians will die and an order of magnitude more will suffer serious injuries during the next decade, unless governments and communities
intervene. Globally, the problem is orders of magnitude greater, with developing countries experiencing particularly acute rates of pedestrian trauma. By any measure, this toll is unacceptable for this most basic of human activities. There is therefore a real need for a radically different approach to achieving major gains in pedestrian safety.
Contributing factors to pedestrian trauma There are existing deficiencies in the design and operation of the roadtransport system that contribute to the incidence and severity of pedestrian crashes First, the extraordinary growth that has occurred in motor vehicle use over the past century has placed pedestrians at a major disadvantage. In particular, large Australian cities have evolved in such a way as to accommodate the rapid expansion of motorised transport. An unfortunate, unintended outcome has been that the least protected users of the road system are at great risk because of increased traffic volumes, vehicle speeds, wider roads and overall emphasis on maximising road capacity for motor traffic. These shifts are major contributors to pedestrian trauma and to the decline that has taken place in walking as a significant mode of transport (Breen, 2002). The high volumes, space requirements and on-going need of drivers for more and more road capacity mean that road and traffic engineers are constantly challenged to find new ways of improving system performance for vehicular traffic. The motor vehicle tends to dominate efforts made to strike an appropriate balance between the mobility needs of the driver, and the mobility and safety needs of pedestrians. For example, the way in which intersections, and traffic signals in particular, are designed and operated in urban areas illustrates how pedestrians are of secondary concern to motorised traffic (Corben & Diamantopoulou, 1996; Corben, Diamantopoulou, Shtifelman & Wilson, 1999). The primary focus of intersection signal design philosophy, as it relates to signal phasing, cycle times and the amount of time allocated, is on vehicle movements. Pedestrians are generally allocated minimum shares of the available time in each signal cycle, with the major determinant of signal timings being the needs of vehicle movements. Second, it is evident that speed is a major determinant of injury risk in the event of a crash, as well as being a key factor in crash risk. Central to the achievement of a safe road-transport system is the successful management of the kinetic energy of vehicles within the system. This must be achieved by keeping sources of kinetic energy separated, dissipating kinetic energy to avoid a collision, or dissipating kinetic energy during a collision in such a way as to avoid serious injury. Kinetic energy is proportional to the second power of speed and so is determined primarily by speed, with vehicle mass playing a lesser role. The relationship between vehicle speeds and the risk of fatal injury to pedestrians is central to the probability of serious injury to pedestrians. Figure
2 shows that the risk of death to a pedestrian struck at 30km/h is around 10 percent, at 40km/h about 20 percent, while for a 50km/himpact, risk rises steeply to about 80 percent. At a 60km/h collision speed, the risk of death reaches 100 percent (Anderson et al., 1997; Ministry of Transport and Communication, 1997).
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Figure 2: Risk of death to a pedestrian as a function of impact speed (Anderson et al., 1997).
Approaches to achieving gains in pedestrian safety While there has been progress in reducing Victoria’s pedestrian trauma problem since 1990, it seems that only a small part of past reductions could be attributed to programs specifically for pedestrians. Indeed, the approach to pedestrian safety specifically has had, at best, moderate success with only incremental reductions in pedestrian trauma. The only noticeable gains seem to have been achieved through generalised, state-wide speed enforcement programs targeting compliance with existing speed limits by drivers and riders. Traditional approaches to reducing pedestrian crashes have had, at best, moderate success. Many countermeasures aimed to reduce pedestrian trauma that have been considered over the past decade stem from an underlying goal of balancing pedestrian safety with driver mobility, economic development, commercial interests, public transport performance and the long-standing professional beliefs of traffic engineers and road builders. However, the term ‘mobility’ has rarely been defined in specific detail and so it raises the possibility that the critical task of balancing safety against mobility may be carried out in a manner that is subjective and therefore does not necessarily lead to optimal outcomes. It is possible that the position adopted by road authorities may be characterised by: •
A dominant emphasis on maximising efficiency in the movement of vehicular traffic
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Use of the concept of Level-of-Service to describe the quality of services provided by the road-transport system, usually in terms of convenience of travel and safety.
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The application of ‘warrants’ by road authorities for the provision of pedestrian signals or other crossing types – these warrants have a strong tendency to preclude the installation of facilities, other than in quite specific justifiable circumstances
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Solutions to pedestrian issues and problems have tended to be sitebased rather than system-based, and seemingly highly reliant on education, promotion, publicity and enforcement to make pedestrians (and drivers) function safely, even though the system often imposes demands that exceed human capability for many users of the system
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An apparent over-reliance by those responsible for the design and operation of the road-transport system on the road traffic regulations, and associated signing and signals, to keep pedestrians and vehicles safely separated.
Achieving safe walking environments Safe walking is both highly desirable for its own sake, but also capable of actively contributing to the achievement of numerous important goals of society. For a variety of reasons that benefit society as a whole, governments, their agencies and associated professional groups have been vigorously promoting walking for some years. As a consequence of this heavy promotion, governments have an obligation to make walking safe, even if there is presently limited evidence that people can be successfully shifted from travel by private car to walking/public transport.
Re-thinking our approach This continual tension between the safety needs of pedestrians and the mobility needs of drivers has been a major impediment to progress in creating safe environments for pedestrians. A breakthrough on this issue could be of major consequence in enabling many known pedestrian countermeasures and initiatives to be implemented system-wide, rather than being limited to a location-specific level, where the demands on traffic capacity are not under serious threat. A number of European countries have recognised the problems that lie ahead with the strategies of attempting to meet the demand for more road space. There is now a major push promoting walking and cycling, and investing to increase public transport patronage. If pedestrians are to receive greater recognition within the road-transport system, it is vital that planning and provision for them occur in an explicit, consistent, systematic and integrated manner.
The development of a new philosophy and a set of over-riding principles that define how the road-transport system should ‘look and operate’ will help to ensure safe and convenient pedestrian movement. In order to support individuals to lead active and meaningful lives, and participate in various aspects of community life, both the safety and personal security needs of all pedestrians, including young children, the aged and those with disabilities, must receive greater attention and priority. Pedestrians (and cyclists) should be given the greatest level of protection, with attention given to the development of road hierarchies that give first consideration to the most vulnerable road users (Catford, 2003). The needs of these unprotected groups should define the standards within which all other modes of transport must operate. In recent years, a number of countries in Europe have taken radically different directions in road safety and these are strategies that we can learn from. In particular, the approaches that have merged from the Netherlands, Sweden and Denmark explicitly attempt to accommodate the safety needs of the more vulnerable road users. Both the Dutch ‘Sustainable Safety’ and the Swedish ‘Vision Zero’ philosophies are founded on strong ethical platforms and state that no individuals should be killed or seriously injured when using the roadtransport system legally. Another example of the ethical basis of ‘Vision Zero’ is that it is unacceptable to trade human life and long-term health within the road-transport system for other benefits in society, such as travel time and vehicle operating cost savings. In Sweden, for example, the notion of ‘the good journey’ has been formulated in terms of three simple goals, i) good accessibility for all citizens, including children, seniors and people with disabilities, ii) safety, and iii) a good environment (Wramborg, 2005). The above philosophies are given effect through a number of principles for the design and operation of the road-transport system and include: •
Road function – categorisation of roads and streets according to their function and the speed environment that should prevail
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Human biomechanical tolerance – the system should be designed and operated within the biomechanical tolerance limits of humans to violent forces
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Safe speed environment – avoidance of large differences in mass, speed and direction of travel and maximum permissible speeds to avoid exceeding the biomechanical tolerance of road users
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Good urban design – safe pedestrian environments are a natural consequence of designing the traffic environment in ways that either separate pedestrians from traffic or that create urban form within which is it intuitive to drive at inherently safe speeds
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Predictable use of roads – design and operation of the system to avoid uncertainty among road users
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Investment strategy – it is unethical to trade the monetary value of human lives saved and injuries prevented with the monetary value of increases in travel time
Measures to create safe and comfortable walking environments Stemming logically from the above definitions of philosophy and principles are a number of practices that can ensure the achievement of the higher-order goals. Importantly, remedial action to eliminate the existing deficiencies in the design and operation of the road-transport system that contribute to the incidence and severity of pedestrian crashes offers a highly effective means of minimising or reducing pedestrian trauma over the long term. To be successful with remedial action, it is imperative to be able to direct any physical improvements to those parts of the road-transport system that present the greatest risk to pedestrians, that is, in high activity/commercial centres. Furthermore, the choice of countermeasure is of fundamental importance to achieving safe pedestrian environments. If real and lasting improvements in pedestrian safety are to be made, four broad countermeasure objectives must be considered. These include: improved separation between pedestrians and vehicles; moderation of vehicle speeds; reductions in road widths and traffic volumes; and, education, promotion and publicity. Separation between pedestrians and vehicles Separating pedestrians from vehicles, either in time of space, is common practice. While traffic signals and other types of pedestrian crossing have been widely used in this way for many years, efforts to design and operate signals to provide a consistently high level of safety for pedestrians have been unsuccessful. Some 20 to 30 percent of Melbourne’s reported pedestrian casualty crashes occur at traffic signals or pedestrian crossings, while many more pedestrian crashes occur in their vicinity (Corben et al., 1999; Corben, Deery, Diamantopoulou, Shtifelman, & Wilson, 1999). Successful spatial separation, through infrastructure development (e.g., pedestrian bridges or underpasses, or grade-separated pedestrian precincts) has been rare. Many pedestrians find such facilities inconvenient, lacking in personal security and choose not to use them, while road agencies typically find them too costly, other than in special cases. Speed reduction In many cases it will be preferable to provide effective separation between pedestrians and vehicles. However, in other situations it will be impractical in the medium-term future to provide separation that is truly effective. In these circumstances, moderation of vehicle speeds to low-risk levels will provide a highly cost-effective option, either until effective separation becomes possible or, as a long-term, sustainable solution that will offer many other benefits to local communities. Not only can changes in speed fundamentally change crash and injury risk for pedestrians, but it does so for all road user categories, is relatively inexpensive to implement, has a number of important
environmental and amenity advantages, and is likely to have only a minor impact on the mobility of the motor car in most urban settings. Speed limits are a powerful measure to reduce vehicle speeds in high pedestrian activity areas. There is compelling evidence of the effectiveness of reduced speed limits, and lower travel speeds in reducing pedestrian trauma. Even small reductions in urban speeds can provide sizeable reductions in crash and injury risk (Corben & Diamantopoulou, 1996; McLean, Anderson, Farmer, Lee & Brooks, 1994). A recent study of the impacts of the introduction of a 50km/h default general urban speed limit throughout Australia (Haworth, Ungers, Vulcan & Corben, 2001) found that the proposed reduction to 50km/h would save 3,000-4,000 casualty crashes per annum and over 12,000 property damage crashes per annum, nationally, while adding just eight to nine seconds to the average trip time of individual drivers. While speed limits are intended to define the maximum speed (i.e., that should not be exceeded), drivers are required to drive at an appropriate and safe speed for the conditions. Frequently, this does not happen. Most drivers and riders have known (until recently) that they can exceed the speed limit in urban areas by as much as 10km/h in 60km/h zones before they may be penalised. Thus, enforcement is only partly effective in containing speeds to maximum levels that are already too high for safe operation of the roadtransport system (Oxley & Corben, 2002). Supporting measures can be introduced that aim to calm traffic in high-risk areas. These measures, such as road narrowing, road re-alignment, alternative pavement textures, aim to indicate to drivers that speeding is not appropriate and that pedestrians have priority. Examples of countermeasures introduced in Victoria and their effectiveness are described below. A programmatic approach was taken to improving pedestrian safety in metropolitan Melbourne and a regional city of Victoria during the late 1990s and early 2000s. A number of pedestrian crash countermeasures were implemented in several municipalities and included behaviour change programs that targeted high-risk shopping areas and other locations where pedestrians and vehicles mix, as well as a range of engineering treatments at high-risk locations. Specifically, the Cities of Port Phillip and Stonnington introduced: •
Pedestrian fencing, usually near traffic signals, to guide pedestrians to safer crossing locations;
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Painted strips between tram tracks to act as a pseudo-median;
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Coloured cross-walks at traffic signals to highlight to turning drivers, the potential for conflict with pedestrians;
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A 50km/h speed limit (reduced from 60km/h) over a distance of some 800m in a suburban arterial road shopping strip; and
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Changes to traffic signal timings, in the form of reduced signal cycles to increase pedestrian crossing opportunity.
In terms of speeding behaviour, these countermeasures generally resulted in: •
A reduction of average free speeds (by about 7.5km/h to 20.8km/h), predicted to result in average reductions of 2 to3 percent in probability of fatal pedestrian crashes and 15 percent in probability of serious injury pedestrian crashes;
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A reduction in mean free flowing speed (by a statistically significant 1.3km/h), predicted to reduce fatal pedestrian crashes by around 11 percent, serious casualty pedestrian crashes by 8 percent and minor severity casualty pedestrian crashes by 6 percent; and,
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A reduction in of 15 percent in the proportion of vehicles travelling at or above 50km/h).
Another initiative aimed to reduce crash and injury risk for alcohol-affected pedestrians at signalised intersections, namely the ‘dwell-on-red’ form of modified traffic signal operation (Lenné, Corben & Stephan, 2005) was evaluated to assess the effectiveness of this measure on the speed behaviour of approaching drivers. The ‘dwell-on-red’ operation involves displaying red to all vehicle directions during periods of low traffic volume, so that drivers approach high-risk intersections at lower speed than if a green signal were displayed as the approached. Once detected by vehicle sensors embedded in the road pavement close to the stop-line, drivers would receive a green signal in the normal way, and when vehicle demand has temporarily ceased, the signals would revert to red in all directions. Vehicle speeds were measured at two points on the approach to the pedestrian cross-walk at the intersection. The first measurements was at the minimum distance required for a driver to stop a vehicle before reaching the cross-walk assuming typical perceptionreaction times, normal values of coefficients of friction between tyre and road surface, and stopping distance profiles. For an intersection situated within a 50km/h speed limit, the critical distance before the cross-walk was approximately 30m. The second measurement was at the crosswalk and was intended to indicate a measure of the risk of death or serious injury being sustained by a pedestrian struck on the cross-walk. The main findings were: •
19 percent reduction in mean speed at 30m from cross-walk after treatment;
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Increase in proportion of vehicles travelling
