- TEORÍA RETÓRICA CLÁSICA SOBRE LA PROSA ARTÍSTICA

Most scientists nowadays agree on the anthropogenic nature of climate change. The transport sector contributes to climate change through the emission of greenhouse gases, particularly through the combustion of fossil fuels. In fact, in 2010 the transport accounted for 14 percent of worldwide greenhouse gas emissions (IPCC, 2014). Furthermore, private car use is the

“second biggest contributor to greenhouse gas emissions in the transport sector” (Chapman, 2007: 357). Whilst fuel consumption is quickly depleting our natural resources, car usage causes social and economic problems such as congestion, noise pollution, and accidents (Kingham, Dickinson & Copsey, 2001; Loukopoulos, Jakobsson, Gärling, Schneider & Fujii, 2004; Eriksson, Garvill & Nordlund, 2006; Howarth & Polyviou, 2012; Van Wee, 2014). Besides the impact on the environment, transport-induced pollution directly affects public health by its relation to diseases such as asthma, bronchitis, and, through lack of exercise, obesity (Banister, 2008; Howarth &

Polyviou, 2012; Sietchiping, Permezel & Ngomsi, 2012; Van Wee, 2014; Van Wee & Ettema, 2016).

The negative externalities of private transportation are aggravated by a drastic growth in private vehicle ownership and a decrease in vehicle occupancy, particularly in urban areas (Saleh

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& Farrell, 2007; Howarth & Polyviou, 2012; Gwilliam, 2013; Järv et al., 2014). Not only in the developed world, but also in the developing world the growth of private car ownership goes hand in hand with a decrease in vehicle occupancy rates. In Cape Town, South Africa, for instance, both the absolute and the relative number of registered vehicles have increased in the past decade. In addition, it was found that amongst the employees of several large firms in the Central Business District, “single occupancy vehicles (SOVs) accounted for 79% of employee private car use, (which in turn accounted for 59% of the modal split)” (Behrens, Adjei, Covary, Jobanputra, Wasswa & Zuidgeest, 2015: 413). Furthermore, while developed countries are still responsible for 70 percent of the worldwide transport related greenhouse emissions, the relative contribution of upcoming economies such as China, India, and South Africa is expected to grow significantly in the next decades as a consequence of these developments (Hickman &

Banister, 2010).

In the developing world, the need for adequate transport demand management, combined with integrated land and transport planning, is even more pronounced. In Sub-Saharan Africa, for instance, as one of the fastest urbanising areas in the world, the demand for transport will increase drastically in the coming decades (Candiracci, Schlosser & Allen, 2010). Often against the backdrop of an already inefficient transport system, the transport crisis not only threatens public health and causes environmental degradation; it also jeopardises urban mobility and thus the primary product of a transport system: accessibility (Candiracci et al., 2010). Accessibility is crucial for both economic and social development because it provides people with access to other people, goods, jobs, and urban amenities.

It is due to the current environmental crisis, as well as the transport crisis in many areas around the world, that TDM became a component of transport planning. In South Africa, for example, the National Land Transport Act (Act 5 of 2009) requires municipalities to formulate and implement TDM techniques in their transport planning. It was recognised that, whereas technological advancements may help reduce some externalities of private vehicle use, some of the issues (such as congestion) can only be resolved if private vehicle use is reduced (Wall, Brög, Erl, Ryle & Barta, 2011). Originating in the United States in the 1970s, the concept of TDM was introduced to exploit the current capacity of transport infrastructure by improved management.

This was a reaction to a declining funding base, as well as a response to environmental concerns.

In addition, the oil crisis around the time, in combination with a high automotive dependency, spurred policy makers to re-evaluate transport planning (Meyer, 1999). As Meyer (1999: 576) states: “In its broadest sense, transportation-demand management is any action or set of actions aimed at influencing people’s travel behaviour in such a way that alternative mobility options are presented and/or congestion is reduced”.

Although TDM in general aims to change people’s or households’ travel behaviour, it is also an umbrella term for a wide range of strategies. Within the domain of TDM, these strategies can be categorised in many ways. One distinction is between hard (or structural) strategies and soft (or psychological) strategies. An example of the first category could be a change to the physical environment, or the usage of economic disincentives such as taxation. An example of the second category could be providing travellers with information about the negative externalities and latent costs of their travel behaviour. Another distinction is between push and pull measures.

Here, push measures refer to policies to steer people away from the automobile, for instance

18 by taxes, as opposed to pull measures, which refer to policies to make alternative travel modes more attractive (Eriksson et al., 2006). See Table 2.1 for examples.

Table 2.1 | Examples of TDM measures ranked from push to pull Travel demand management instruments Push Taxation of cars and fuels

Closure of city centres for car traffic Road pricing

Parking control

Avoiding major new road infrastructure Teleworking

Land use planning encouraging shorter travel distances

Traffic management reallocating space between modes and vehicles Park and ride schemes

Improved public transport

Improved infrastructure for walking and biking

Public information campaign about the negative effects of driving

Pull Social modelling where prominent public figures use alternative travel modes Source: Gärling et al. (2002: 60)

The great diversity in terms of measures and policies within the domain of TDM also means that they differ in terms of cost of implementation, effectiveness, efficiency, and public acceptability (Gärling et al., 2002; Eriksson et al., 2006; Wall et al., 2011). Especially public acceptability, or political feasibility, plays an important role in whether or not a measure will actually contribute to a change in travel behaviour. For instance, there seems to be evidence that push measures should count on lower public acceptability than pull measures. In the context of road pricing, Eriksson et al. (2006) argue that an increase in the perceived level of infringement on car users’ freedom to travel is directly related to a decrease in acceptability. It is on the other side of the continuum that one may find the less coercive measures, referred to, amongst other terms, as soft transport policy measures or VTBC interventions (Bamberg et al., 2011). Cairns et al. (2008: 594) add to this that soft refers both to the response of the traveller as well as the nature of the intervention itself. This means that soft transport measures focus on changing travellers’ current behaviour using psychological and economic incentives rather than changing the built environment itself through infrastructural investments (Taylor, 2007;

Bamberg et al., 2011; Ho, Mulley, Tsai, Ison & Wiblin, 2017).

VTBC interventions come in many forms. Some established examples of VTBC interventions include travel plans that encourage commuting employees not to use their private car; school travel plans that encourage parents not to bring their children to school by private car; ride-sharing schemes; and travel awareness campaigns (Bamberg & Möser, 2011). Well-known examples of schemes that have been promoted and implemented are the TravelSmart®

programme in Australia, the Smarter Choices programme in the United Kingdom, and several travel feedback programmes in Japan. These schemes typically include a number of travel

19 demand management instruments in order to stimulate both individuals and households to reconsider their travel behaviour (Chatterjee & Bonsall, 2009; Zhang, Stopher & Halling, 2011).

Not only do VTBC interventions have a higher acceptability amongst the general public because of their voluntary nature; they are also said to have short-term benefits such as an

‘immediate’ reduction in greenhouse house gas emissions. Moreover, as shown in Figure 2.1, their cost-benefit ratio when compared to large infrastructural developments is potentially attractive. The figure also suggests that voluntary measures are not only less expensive, but are also more acceptable by the public as compared to, for example, financial charging measures such as a congestion charge. In addition, as VTBC interventions aim to stimulate more sustainable modes of travel, they may also come with significant health benefits by their stimulation of more active forms of travel (Graham-Rowe, Skippon, Gardner & Abraham, 2011;

Zhang et al., 2011; Sietchiping et al., 2012). Sustainable mobility thus not only holds benefits for the environment, but also for individual physical well-being (Banister, 2008). As such, present-day definitions of TDM include not only the management of travel demand, but more specifically refer to those interventions that aim to promote more socially, economically, and environmentally desirable forms of transport (Taylor, 2007).

Figure 2.1 | Implementation difficulty versus effectiveness of TDM measures

Source: Behrens et al. (2015: 415)