In 2010 the number of registered cars in the world hit the 1 billion (10⁹) mark (see Ward’s Auto, or, if you want to try some Dutch, Autoweek). This represents a major concern in climate change mitigation. While carbon taxes on private and company cars have been implemented in many places (including in SA), I will argue that the current approach is artificial and is not necessarily achieving what it has set out to do. Some relevant background can be found in my other blog on this topic.
The problems with current policies stem, in my opinion, from the consideration of tailpipe emissions only, the artificial nature of the test conducted to establish official figures for CO₂ emissions and the fact that driver behaviour is not taken into account. Also, how kilometre charging (a form of carbon taxing described here) would differ in its effects from fuel taxes, other than shielding industry (trucks need not pay kilometre charging, but are affected by fuel levies) and those who drive uneconomically, is not clear to me.
Certainly, a question that requires answering is what advantage these carbon taxes on motor vehicles have over simply increasing fuel duties. Here, a number of studies have been done, which have generally found a dramatic decrease in average vehicle fleet emissions since the introduction of these taxes; far more rapid than the slow decline that occurred between 1995 and 2005. In contrast, higher fuel taxes seem to encourage people to drive less, but doesn’t necessarily provide a strong enough incentive to buy a more economical new car. While this may indicate a trend towards people buying more economical cars (certainly, anecdotal evidence from European automotive fora indicates a strong tendency for new car buyers to want to select cars that are exempt from certain taxes or fall into lower company car brackets, for obvious financial reasons), one should be careful in ascribing all the decrease in fleet emissions to such policies. In particular, ambitious binding targets for CO₂ emissions, to be applied to each car manufacturer (charges will be levied on companies that fail to comply) set by the European Union, to come into force this year, would certainly have pressurised manufacturers to improve the efficiency of their products.
As such, the number of cars on the European market that are now fitted with fuel saving devices such as start-stop (which automatically switches off the engine when one stops and then switches it back on when accelerator pressure is applied), brake energy regeneration and low resistance tyres, has increased dramatically in the last three years or so. These changes almost certainly contribute to reduced emissions at a reasonable cost to the consumer (since much of the cost is implicitly carried by the state) and thus it appears these changes should be lauded (more cynically we may ask why we had to wait so long for them to be introduced in the first place).
Other changes have included the introduction of double clutch automatic gearboxes, semi-automatic and sequential transmissions, adaptations to gear ratios, tinkering with engine management and the introduction of electronic power steering. Above all, a trend has emerged that has become known as downsizing – smaller capacity engines, often are fitted with turbo- and/or superchargers, are replacing low stress, larger capacity engines. Here matters become more complicated: tuning and tinkering is generally done to gain advantage over competitors by reducing official emission figures just sufficiently to fall within a lower company car tax bracket, or below the tax-free threshold, in some key market. For example, a car officially emitting just 2g/km less than a primary rival could gain a massive competitive advantage in markets with a large leasing share (such as the UK or The Netherlands). Not only does this favour companies that already have large market share and can therefore afford to spend money on such tinkering, but it potentially also offsets resources that would otherwise have gone into the development of new generation engines with greater efficiency.
Even worse, perhaps, is that evidence from tests conducted by motoring journalists, as well as consumer reviews (see, for example, groenopweg.nl), suggest that there may be no significant real world advantages in many cases; sometimes, so-called green models in practise consume even more fuel than the cars upon which they are based. How can this be? Since manufacturers are well-aware of exactly how the official test to establish fuel consumption and emissions is conducted, they can adjust their engine management, gear ratios and so forth to these artificial conditions. Since the test is conducted under conditions that keep engine stress levels low and smaller force-fed engines increase their consumption far more rapidly at higher engine stresses, the test is substantially biased in favour of downsized engines. This would all be well and good if drivers could be forced to emulate the actions taken under the test conditions. However, apart from the meek efforts to encourage the inclusion of gear change indicators in modern vehicles, little has been done to alter individual driver behaviour, even though studies by the European Union have found that inefficient driving techniques (not including speeding!) can increase emissions by as much as 20% in extra-urban driving environments and as much as 40% in city traffic (approximately equivalent to advances made in engine efficiency over the past two decades!)
Another problem that has come to light with many of these new, supposedly more environmentally-friendly technologies, is reliability concerns. Problems with the distribution chains in the Volkswagen Group’s downsized TSi engines (fitted to models from Volkswagen, Audi, SEAT and other companies) have made headlines in Germany of late, whereas double clutch transmissions have also become notorious for their vulnerability. This leads me to probably the most glaring flaw in the current taxation system: it applies only to exhaust pipe emissions. The effective emissions from sources are simply not taken into account in legislation. These include: more complicated manufacturing processes; more advanced refineries needed to produce the much cleaner diesel required by modern diesel engines with their lower particulate emissions; electricity-intensive aluminium smelting (often done in countries like South Africa that produces cheap and dirty electricity) used to produce lighter parts to contribute to greater fuel efficiency; and especially from having to replace vulnerable parts and produce more new cars to replace old ones that are scrapped because of high taxation levels or government subsidies. Some maverick studies have attempted to include all such variables and have produced extreme results, such as that a Jeep Wrangler is more environmentally-friendly than a Toyota Prius. However, the assumptions made by such studies should be treated with a healthy dose of suspicion, especially given the potential biases of the investigating agencies.
In terms of considering driver behaviour, my personal experience, in driving my dad’s car with a fuel consumption read out on the trip computer, is that being able to see immediately the effects of certain practises in increasing or decreasing consumption has a significant direct impact on my driving style, that is not achieved by watching the demoralising climb of fuel costs at the pump. Perhaps making such read-outs mandatory could begin to achieve what many more complicated measures have failed to realise.
Therefore, while the intention to reduce greenhouse gas emissions from road vehicles may be very noble, there seems to be no guarantee that current policies are actually achieving this goal. I would therefore suggest that to refine legislation, new studies are needed that take a more holistic, global approach to emission control and compare the consequences of rival policies.