Ergonomics has traditionally focused its efforts on the trimurti of human performance: safety, efficiency and satisfaction. But the early years of the 21st century have seen heightened awareness of a new issue on the societal and political agenda – the environmental impact. So far, ergonomics is yet to take up the environmental mantle in earnest, but moving forward it will become increasingly difficult to ignore. There are two key reasons for this: firstly, environmental impacts are a direct result of behavioural choices, so this should be the domain of ergonomists; secondly, it is increasingly a focus of funding and contracts both in the UK and internationally. A UK consortium project known as ‘Foot-LITE’ is aiming to tackle one of the biggest environmental problems: personal transport.
Private car use is often targeted as an area where significant reductions in environmental impact can be made. European statistics suggest that road transport accounts for 19% of the EU’s greenhouse gas emissions. In addition to the considerable environmental cost, personal car use has been getting increasingly expensive over recent years, especially with rising fuel prices and the recent financial crisis. In the summer of 2008, UK fuel prices increased by nearly 50% in a matter of months. Reducing fuel use therefore has benefits both for the individual and society at large.
Meanwhile, safety concerns have not gone away; the decline in road traffic accidents in many developed countries has hit a plateau, despite the EC’s target of a 50% reduction in road fatalities by 2010. New initiatives are needed in order to make breakthroughs in both safer and environmentally-friendly driving. One way in which to achieve both of these objectives is to try and change driver behaviour. Many of the safety and environmental issues can be addressed by a change in driving style, while in the longer-term we may try to encourage modal shift onto other forms of (public) transport. As a behavioural issue, this problem is ripe for ergonomics input. The aim of the Foot-LITE project is to develop a system which will encourage drivers to drive in a safer and greener manner, through both on-board advice in the car and off-line feedback pre- and post-drive. Our role at Brunel University within the project is to determine the behavioural aspects of safe and green driving, and to lead the ergonomics development of the human-machine interface (HMI). One of our first tasks was to help understand what constitutes safe and green driving.
In September 2007, the Commission for Integrated Transport (CfIT) suggested that fuel savings from ‘eco-driving’ can lead to average fuel savings of 5-10%, equating to a financial saving of approximately £100 per year to the average motorist. Other studies suggest the savings could be even higher, but there is a clear message that drivers need advice and timely feedback on how to drive economically. When asked to drive more efficiently, many drivers simply interpret this as driving slower. Whilst it is true that fuel efficiency is at its peak between 60km/h and 80km/h, reducing speed is not the only, nor is it the optimal, strategy for maximising economy, especially considering the implications for journey time. Instead, the focus should be on limiting heavy acceleration and braking, excessive power demand, and high engine speeds.
Numerous driving factors have been linked to eco-driving. The common consensus of advice includes:
- Plan ahead to avoid unnecessary stopping.
- Use moderate engine speeds and a uniform throttle for steady speeds.
- Change gear up as soon as possible using positive (but not heavy) acceleration.
- Avoid sharp braking.
- Use engine braking for smooth deceleration.
Surprisingly, compared to the eco-driving literature, there is a relative dearth of scientific research on how driving style affects safety outcomes. However, what evidence is available suggests that for the most part, adopting an eco-driving style also has a positive impact on safety. Studies of eco-driving training and advanced driver training show improvements both in driver skills and accident rates, in addition to the environmental benefits.
However, safe and efficient driving styles are not always compatible. Some factors that improve efficiency or safety may have confounding effects on the other. For instance, maintaining a constant speed through avoiding braking may compromise headway; travelling in the highest possible gear may adversely affect vehicle control. Moreover, whilst large, heavy vehicles perform well in crash tests, these same characteristics make them less environmentally-friendly than smaller vehicles. The key is, therefore, in providing drivers with the skills and knowledge to change their driving style, and enabling them to make appropriate decisions about the trade-offs between safe and eco-driving. This has come to be known as ‘smart’ driving, and it is precisely the behaviour that Foot-LITE seeks to encourage. For drivers to effectively and positively change their driving style, feedback needs to be timely and constructive. But, needless to say, any in-car interface must not increase workload or the risk of driver distraction, lest we adversely affect the behaviours we are trying to improve! To optimise the positive effects and eliminate the negative is a challenge for the ergonomics of the interface design.
Our first step towards understanding the task constraints (and therefore the information requirements for the HMI) was to conduct a Cognitive Work Analysis (CWA) for the Foot-LITE project. CWA is a structured framework for the development and analysis of complex socio-technical systems, which is purported to support ‘revolutionary’ rather than ‘evolutionary’ design. Within the scientific literature a small number of studies have used CWA and its design corollary, Ecological Interface Design (EID), for in-vehicle HMI design. It therefore seemed wholly appropriate to apply to this project.
The CWA process allowed us to identify a range of sources of information that can be used to feed back to the driver about their driving style. It also highlighted where different behaviours would contribute to safe, or eco-driving, or both. The output of the CWA was applied to an innovative HMI for the Foot-LITE project based on EID principles. Whilst we cannot go into details about the HMI in this article, we consider it to be an integrated, direct perception interface that can potentially facilitate a positive behavioural change while minimising distraction and workload. Future tests in the Brunel University Driving Simulator will evaluate the EID concept to determine its effects on driver behaviour.
Whilst Foot-LITE might not be the only ergonomics project concerned with environmental issues, we do believe that this movement reflects a significant area of potential growth for the discipline. By trying to influence behavioural change by design, ergonomics plays a key role in Foot-LITE. The complementary goals of safety, efficiency and satisfaction may well find an ally in the environmental movement.
Co-author: Stewart Birrell
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