Conference Proceedings

Forgiving Roadsides - A Way Forward

Author - Mr Peter Waugh
Director - Infrastructure
BSD Consultants
2 Bagot Road
Subiaco WA 6008

Ph: 08 9273 3888
Fx: 08 9388 3831
Email : winfra@bsd.com.au

INTRODUCTION

The understanding of the causes of road trauma has been a continuing challenge to the road safety community. A traditional approach has been to gather all the data or "facts" about crashes and to statistically analyse these to determine causes. Use of this analytical approach leads to the well known Venn diagram shown as Figure 1.

Figure 1

This type of approach is valuable but its effectiveness can be dampened by the following:-

High reliance on adopted causal framework
Data May be incomplete, doubtful or non-existent
Reactive rather that preventative

It also guides us to consider sub-sets of three key areas namely people, environment and vehicles and to develop actions based on these. Hence campaigns against speeding, drink driving, road blackspots and "unroadworthy" vehicles emerge to improve road safety. We understand these "causes" are inter related but the integration of specific actions to maximise the overall impact is difficult to achieve in practice. Programs therefore tend to address specific issues somewhat in isolation although there maybe an overall framework to ensure some outcome relationships. The approach is reduce these "identified causes" leading to a fall in the aggregate road trauma leading to significant community benefits.

This approach has merit and evidence from Victoria (Cameron Newstead and Vulcan, 1994) indicates that large reductions in casualty crashes can result from carefully planned specific issue campaigns. The concern is that after a large reductions in crashes during the early years of these campaigns there are now indications that there is a levelling out occurring in fatalities and crash rates per capita in Victoria (ATSB 1999). Perhaps looking at post crash data has limits in terms of ensuring a continuing reduction of crashes over time and another approach is required to supplement this current strategy. The most encouraging new approach which would provide complementary crash reduction is the vision zero approach that has been adopted in Sweden (Tingvall, C and Haworth, N 1999).

VISION ZERO

In 1997 the Swedish Parliament passed new road safety legislation which was based on the promise that "eventually no-one will be killed or seriously injured within the road transport system". The philosophical basis is that society cannot ever accept that any person is killed or seriously injured in the road transport system and must take all steps to prevent this road trauma.

This approach represents a significant philosophical change from conventional road safety strategies. It focuses on the optimum safety of the road transport system and shares responsibility for this between designers/planners of the transport system and the road users. The ultimate responsibility rests with the designers of the road transport system who must adjust the system if users fail to meet their responsibilities.

Tingvall and Haworth (Tingvall, C and Haworth, N 1999) have listed two ethical rules that can provide guidance to road system designer. These are:-

"Life and health can never be exchanged for other benefits within society.

Whenever someone is killed or seriously injured, necessary steps must be taken to avoid a similar event".

I believe that if road system controllers adopt the vision zero philosophy and employ it fully then major improvements to road safety will follow. In particular if road designers and planners adopt this approach to make our roads forgiving of user errors such that deaths and serious injuries are prevented then the improvement in road safety will be significant and enduring.

FORGIVING ROADSIDES AND VISION ZERO

It is accepted that currently the roadside has hazards that can, and do lead to fatalities and serious injury in Western Australia. In 1999 there were 62 fatalities and 524 hospitalisations reported as "hit object". This represents 33% of the fatalities and 28% of the hospitalisations reported for that year. And it is not just a rural problem with more than 28% of these fatalities and 22% of the hospitalisations reported in the metropolitan area. The listed "causes" of these crashes have been varied with factors such as fatigue, speed, alcohol, inattention, inexperience and weather seen as major contributing reasons.

Under a Vision Zero approach a roadside needs to be designed to prevent fatalities and serious injuries. What does this mean? The first step is an acceptance that crashes cannot be totally avoided. The next step is to ensure when these crashes do occur then the circumstances are such that the human body does not suffer any forces above the injury tolerance level. Obviously the two fundamental approaches to be adopted in achieving the vision zero goal are to eliminate crashes that cause forces higher than the human tolerance level or to increase the level of human tolerance for injury. The former is the focus of this paper where it is examined in terms of the roadside environment. The approach however can be used in all aspects of road safety improvement.

What is the roadside? In this paper the roadside is taken to be that area outside of the space provided for road user movement. It includes median areas, all signs, service poles, bus shelters, culvert and bridge structures, trees, embankment slopes but excludes the roadway, footpaths, bus embayments and dual use paths.

What does a vision zero approach mean in practice for road designers. To understand this we need to look briefly at the traditional approach to design. This approach is based on the interpretation and application of design standards. Standards are tools to assist designers in providing the best designs to meet the project objectives. The standards specify the limits, which should not be broken but do not in themselves provide the design detail. Because standards are necessarily general in nature each road design is an aggregation of all the project specific decisions made during the design process. In other words, the designer through professional judgement and astute use of standards and current practices determines the final design that is best suited to meet the project objectives. It should be noted that one objective that is always included in all projects is to maximise the safety of all road users.

All of the above is consistent with the Vision Zero approach but it is in the application of this process where differences emerge. For instance when analysing the roadside hazards that are present a designer currently looks at several options including:-

Remove hazard from site
Shift hazard clear of vehicle recovery zone ie the zone in which a vehicle travelling at its normal speed can be controlled and/or stopped.
Protect hazard using an appropriate safety barrier
Redesign hazard to reduce crash severity eg, frangible light poles
Highlight the hazard through lighting, signing etc
Costs and benefits of options

Clearly options 1 and 2 meet the vision zero objectives. Options 3 and 4 May meet vision zero objectives if any crash that is likely to occur does not lead to death or serious injury. Options 5 and 6 do not meet the vision zero objectives. In theory this seems to be relatively straight forward but in practice there are many very complex issues that will need to be resolved in the application of the vision zero philosophy.

To help them decide which compromise solution is best designers look to risk analysis techniques but taking into account their constraints of budget and the physical environment (including road reserve widths). This approach implies that there is some serious injury or death risk to road users that is integral to the final design and this is not an acceptable philosophy for the Vision Zero designer.

For instance one compromise approach is to provide clear zones which are free from roadside hazards. These zones are such that full vehicle recovery is not possible but provide an area that meets some "manageable" risk level. For instance Figure 3.9.2 from the Vic Roads Road Design Guidelines gives the road designer some risk levels for use in the design process. It should be noted that the speed chosen in the graph is the 85^th percentile speed. This means that there are some road users who are at greater risk because their travel speed is higher - a fact that is known by the designer. This again is not acceptable if we are to meet the Vision Zero objectives.

This leads to the inevitable question from road designers. "Am I supposed to design for the general road user or those road users who are high risk takers, have poor skills, are tired or affected by alcohol etc? In a philosophical sense the answer is yes to the latter if it is foreseeable that such drivers will be or are on the road being designed. For instance clearly if there is enough data to determine an 85^th percentile speed then the maximum travel speed is known and can be factored into the design. Remember the designer is ultimately responsible for ensuring there is a safe road system that does not cause death or serious injury under a vision zero approach.

The application of a vision zero philosophy cannot happen overnight. It does however present a goal that we should now adopt and, begin to formulate over strategy to achieve it. There are some fundamentals we need to understand and these will assist us to prepare a workable strategy to improve road safety through the Vision Zero philosophy.

The first is that a vital element in the vision zero design approach is the tolerance level of the human body in crashes. This is influenced by the vehicle and the infrastructure elements of the total transport system. There has been, and continues to be (albeit slowly in my opinion) improvements to in-car safety. It would be better if more in car safety devices could be provided for all cars such as a guaranteeing seat belts are being worn, drivers being sober and alert, maximum speeds limited to some agreed figure or better still electronically limited to the set speed limit. This is an important area of road safety improvement however it needs significant community pressure to bring about the sufficient political will to force the necessary changes.

The infrastructure is the other key element. It is the interaction of the infrastructure with travel speeds and the manner in which the infrastructure manages potential conflicts that are important here. A pedestrian, who is vulnerable , requires vehicle speeds to be below 20kmh to prevent death or serious injury. If the speeds cannot be kept to this level then vehicles and pedestrians May need to be separated physically. Similarly roadside hazards need to be located outside the full recovery area for vehicles travelling at the known travel speed or physically separated/protected.

Another significant issue is the number of hazards placed in the road reserves by utility service providers. Of particular concern are the poles carrying overhead power supplies. These are large and close to the roadways mostly unprotected from errant motorists. Ironically from a road safety point of view if these poles are damaged they are heavily reinforced thus presenting a higher risk to road users, From a road safety viewpoint the sooner all such services are underground the better it will be for the community. To provide frangible poles is a common compromise solution. These poles, however, are not frangible for motorcyclists thus exposing these road users to unacceptable (in vision zero terms) levels of injury. This is a particular concern in the Perth Metropolitan Area.

There are many other systemic issues that need to be addressed both in urban areas such as undivided for lane roads, insufficient median widths, trees and other natural hazards unprotected within the recovery zones, open drains, buildings, culvert end walls to name a few. Perhaps to look at one simple example might help understand the enormity of the change required to meet vision zero objectives.

Consider the impacts of applying the vision zero philosophy on a section of road traversing an area of mature forest. Each tree with a trunk diameter greater than 100mm represents a potential threat to life or serious injury in a crash at normal highway speeds. The vision zero designer faces a range of alternative solutions from clear felling (ie remove hazard) to reducing the motorist's travel speed such that if they make an error they will not be killed or seriously injured when they hit a tree. This May mean for example a travel speed of 40kmh is appropriate dependant on the distance of the trees from the road edge. Note it is travel speed that is important here not the speed limit.

Clear felling is generally not seen to be an acceptable solution to the community but nor would a 40kmh travel speed on a rural highway. The goods transport industry costs would rise significantly and in a large state like WA would potentially cause greater increased social costs. This means a compromise solution such as some form of safety barrier would need to be installed. Since safety barrier is a hazard in itself its design would need to take account of the road travel speed so that any impacts would not lead to death or serious injury. Thus safety barriers plus travel speed reductions May be required to meet the vision zero objectives. There May be other solutions but the implications of the vision zero approach can be seen in this example. In conventional terms this approach would be seen as expensive but since the over-riding objective of vision zero states that it is not acceptable for any person to be killed or seriously injured on the road transport system it is an appropriate solution.

THE WAY FORWARD

Obviously the transport system cannot be transformed to meet Vision Zero objectives in the immediate future. The resource cost, the disruption to current transport operations and the cultural changes required preclude this type of transformation.

There are to me, some logical general actions that we, as responsible stakeholders in the Transport system should commit to so that the transformation process can begin.

The first is the adoption of the vision zero objectives by all road safety stakeholders in WA politically and including political, government organisations and the community.

The second action is for the vision zero philosophy to be applied to all new transport projects in WA. It would seem reasonable, as a first iteration, to assume that normal road user behaviour would apply in completing the designs.

The third action is to educate and convince the community on vision zero objectives and benefits. Such a program would need to reflect on both the positive benefits and the negatives that May be perceived under the current economic rationalist frameworks for projects funded by Governments.

A fourth action is to expedite improvements and installation of in-car safety devices. Clearly this is most likely to begin with new vehicles but would need to extend, in time, to cover older vehicles. It would also be important to ensure adequate research is conducted to better understand the injury tolerances of humans in transport crashes. This applies to both in-car systems and external crash protection devices.

Looking specifically at roadsides the application of vision zero objective in planning and design of new works and major improvements should commence immediately after their adoption by Government. These could also be used in review processes such as road safety audits to highlight aspects that have the potential to cause road user death or serious injury.

All poles (power, light, sign etc) need to be removed from the vehicle recovery area or protected by measures that keep potential injury to minor levels. This should also apply to other hazards such as landscaping boulders, buildings, culvert end walls, trees to name a few. As indicated in the simple example quoted earlier this May mean a combination of protection, removal and travel speed reductions. This approach will need to be implemented on a priority basis and is likely to concentrate on "black roads" identified either by past crash history or risk analysis techniques. There will also be certain systemic measures that can be introduced in an ongoing way such as the removal of power poles from urban road reserves, lowering of general travel speeds and median protection between opposing traffic. The service authorities must, I believe, bear some responsibility removing hazardous poles from road reserves to meet their community delegations.

The current moves to improve the road landscapes include planting of flowers, trees and shrubs. These should not include any unprotected trees that are more than 100mm in diameter within the vehicle recovery area for the particular road. Adoption of this policy could save much future road trauma.

In conclusion I see the adoption of vision zero objectives in road safety planning, design and operations as an imperative if we are to make significant gains in reducing road trauma. These objectives need to be embraced by those who control the transport system, the suppliers of all vehicles and transport system accessories, users of the road reserve such as service providers and advertisers and the road users to maximise the benefits of closing in on these objectives. This will be a long term process but we must start now.

A significant contribution can be made by adopting vision zero objectives in the planning design and operation of roadsides now. Immediate improvements in fatalities and serious injury will result from removal or protection of hazardous roadside objects from new projects and progressively over the road transport network.

I urge all organisations responsible for managing our road transport system including politicians to adopt the vision zero objective in all their planning and design and put peoples safety as the absolute priority in these processes. It will take courage to take on the "value for money" syndrome which controls much of our infrastructure decision making and state that the elimination of death and serious injuries on our transport systems is the ultimate value in our society. I believe we must take this brave way forward for the benefit of all the community today and tomorrow.

85th Percentile Speed (km/h) Clear Zone Width on Fill

REFERENCES

Austroads Road Safety Audit

Cameron, M, Newstead and Vulcan, P, (1994) "Analysis of Reductions in Victorian Road Casualties 1989 to 1992"

Proceedings 17^th ARRB Conference, Gold Coast, Queensland

Australian Transport Safety Bureau "Road Fatalities Australia" http://atsb.gov.au, May 2001

Tingvall, C and Haworth, N "Vision Zero - An Ethical Approach to Safety and Mobility" 6^th ITE Conference Road Safety and Traffic Enforcement: Beyond 2000, Melbourne September 1999

Kirov C, Legge M, Rosman DL "Reported Road Crashes in Western Australia, 1999" Road Safety Council September 2000

Vic Roads (1996) "Traffic Engineering Manual Road Design Guidelines".

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