Environmental Engineering Reference
In-Depth Information
of spend. There are certainly concerns over the reporting and evaluation of results (Bonsall,
2009), the longevity of behavioural change, and the ability to spread take up over a wide
population - there are likely to be diminished returns when spread beyond the initial enthusiastic
take up. Certain cohorts of the population have little interest in reducing their levels of car
use (inter alia). However, the effectiveness and cost effectiveness of investment appears to
compare well against other interventions, and despite some concerns, investment should be
increased (Sloman et al., 2010).
Although we will discuss later the sociological and psychological dimensions to travel
behaviour, and the need to further understand these, the smarter choice measures are trying
to understand and influence behaviour, and they provide an important initial step. The scale
of impact is closely linked to the level of associated hard infrastructure investment and the
location of development; and this is perhaps the point that is important, namely that any efforts
that are likely to reduce travel to any degree are likely to include 'hard', 'soft' and planning
interventions, and they cover the full range of interventions within the sustainable mobility
paradigm. Working within these fields, with little wider action, is not likely to have large
impacts on travel behaviour. Hence multi-disciplinary working within and beyond transport
planning is important. This scenario assumes a medium intensity application of smarter choice
behavioural measures to reduce travel CO2 emissions.
PP9 slower speeds and ecological driving:
Much of the conventional thinking in transport
planning is designed to speed traffic up, as congestion and delay are seen as 'wasted' time,
resulting in loss of time that could be productively used on other activities. This raises important
issues that need resolution. It has been demonstrated that lower speed limits, including less
lane switching, may allow traffic to flow more smoothly, thereby increasing capacity. There
are also major environmental and safety benefits, and potentially economic advantages from
slower speeds and reduced traffic volumes. There has been a clear move towards lowering
speed limits in residential areas (home zones) and in other locations (e.g. around schools or
on routes with important design quality), where priority has been reallocated to people. Potter
et al. (2001) advise on the safety benefits of slower speeds, namely that drivers of both cars
and goods vehicles could typically save between 5 and 10 per cent on their fuel bills by
adopting more fuel-efficient driving behaviour, and in some cases, a 20 per cent improvement
in fuel economy could be achieved. There are therefore strong arguments to reduce the speed
and volume of vehicles in some locations.
Lower speeds need to be combined with awareness programmes and better driving techniques
to reduce fuel use. Ecological driving skills have been developed in the Netherlands and
Germany and include simple measures such as driving at moderate speeds, avoiding excessive
acceleration and harsh braking, changing gears at low engine revolutions, driving in the
highest comfortable gear at any given speed, avoiding unnecessary use of in-car equipment
(especially air conditioning), keeping tyres inflated and reducing unnecessary loads (Anable
and Bristow, 2007).
This package has the potential for substantial immediate and long-term benefits if take up
is high in terms of reduced speeds and changed driving styles. The major problem is likely
to be in achieving and enforcing changed driving styles in the mass market. Slower speeds
provide extensive savings, for example, with potential for some 15-20 per cent reduction in
carbon emissions if a maximum speed limit of 80 km/hr is introduced on motorways and
trunk roads, with lower speeds on other roads, both with effective compliance. Although the
fuel use and speed value curves for new cars are flatter than those for older cars, there are
