SUVs and 4x4s — How can these vehicles remain acceptable?

It is now a while ago that Sports and Utility Vehicles (SUVs), sometimes referred to as 4x4s, appeared on the European market in various forms and guises, either as derivatives of the legendary Range Rover, or as inflated versions of conventional cars. Both kinds of vehicles have enjoyed and do surprisingly still enjoy quite some popularity; sales figures continue to rise. It is a mystery to me how this type of vehicle can do so well in the context of climate change and limited resources on our planet. If anything, the world needs fewer and more energy efficient cars, both in terms of production and operating energy expenditure per accumulated person-miles. Most importantly, however, shared forms of transportation using appropriate vehicles may provide the biggest energy and resource gains, including autonomous forms of transport in due course. In the following I would like to explain my issues with SUVs and vehicles that aspire to be SUVs, from a European perspective, as a cyclist in Cambridge, UK. If you, dear reader happen to own and drive such a vehicle, any contentious claims made below do of course not apply to you.

Energy Consumption and Ecological Footprint

First, the energy consumption for the production of an SUV and consequently its ecological footprint is likely to be larger than the energy needed for the production of a mid-sized vehicle transporting the same number of people. A mid size car weighs around 1500kg whereas a mid-sized SUV weighs in excess of 2000kg, i.e. an SUV is at least 1/3 heavier (see 1). It is perhaps safe to assume that the energy spent in production and decommissioning is proportional to the mass of the vehicle, which will of course be reflected in the price. However, it is a lot of unnecessary mass, e.g. sturdy chassis, big wheels, 4x4 drive train, and, as a consequence of all that additional mass, a larger engine in order to deliver the power necessary to move the whole mass. The powerful engine, in turn, increases the total mass even further. In summary, the energy needed for production of an SUV can be assumed to on average 1/3 higher than for an average vehicle.

Second, the operational energy expenditure is all down to the physics of motion. There are two major driving scenarios: slow speed stop & go city driving and constant, high speed motorway cruising.

As for city driving, the average energy consumption on a city circuit is roughly proportional to the mass of a vehicle for the following reasons. In this driving situation the vehicle repeats many acceleration and deceleration cycles. Energy has to be invested to accelerate the car up to moderate speed, with the energy spent being mostly proportional to the vehicle mass, only in order to dissipate all that stored kinetic energy during the deceleration period, in general through friction braking, i.e. turning energy into heat. Even if the SUV used a hybrid or electric drive train, regenerative braking can only harvest a fraction of the energy spent during acceleration (see 2). Since the energy expenditure in the city is mostly proportional to mass, SUVs spend on average at least 1/3 more energy than an average vehicle transporting the same number of people. The situation is exacerbated by the fact that quite often only one or two people occupy the SUV in a city, leading to even more energy being wasted if compared to an appropriate city vehicle weighing perhaps around 1000kg only, e.g. a Smart or Toyota IQ.

The situation is not so different when driving an SUV at constant speed on the motorway. For a longer period of a motorway journey, in any vehicle, a continuous energy expenditure is needed to maintain its speed. The resulting accumulated energy expenditure due to constant motion is significantly higher than the energy needed to accelerate the vehicle up to cruise speed. Per unit of time, the continuous energy expenditure or constant power to maintain the vehicle’s cruise speed is roughly proportional to the cube of the speed, and linearly proportional to the drag coefficient and vehicle cross section. Since SUVs are usually rather box shaped the drag coefficient is at least 1/3 higher than for a normal and aerodynamic passenger vehicle (0.45 or more for an SUV as opposed to 0.33 or less for normal sedan, see 3, Part II). Moreover, the cross section of an SUV is also at least more than 1/4 larger than for a normal car, or even more (2.0m W x 1.8m H = 3.6sqm or more for an SUV as opposed to 1.9m W x 1.5m H = 2.85sqm or less for normal sedan, see 1). Both factors combined as a product called drag area, the amount of power needed to plough through the air is in the order of 70% higher than for a sedan type vehicle transporting the same number of people.

In a similar vein, damage to the road is related to the weight of vehicles, see (4) for a detailed report. The fourth power law found in this report and in literature in general applied to SUVs, being at least 1/3 heavier than average vehicles, results in at least 3 times more damage, wear and tear of the road surface than average vehicles. Perhaps, as a consequence, the road tax should contain a more fine grained relationship to the weight of vehicles reflecting the fourth power law, adding market feedback to the cost of running SUVs on public roads and hence diverting the cost more to those who cause it.

Having shown that an SUV consumes more energy per person transported for the production plus decommissioning of the vehicle and even more for every mile driven, whether in the city or on the highway, what is the point of doing that in the context of climate change? How can anybody with some notion of responsibility for the planet justify driving such a vehicle? It is a folly, it is irresponsible and unacceptable. It sounds to me like somebody feasting every day while knowing that food is becoming scarce, and thinking that it is fine as long as he or she is paying and can afford it. Unfortunately, it is not fine; as with food, it is anti-social to consume more resources than needed. An SUV is an anti-social vehicle.

Vehicle without Purpose nor Utility

On a more general note, whenever I buy something I try to think about the requirements, the purpose and utility. I fail to see the utility in the Sports and Utility Vehicle. If it is utility you are after, then it really depends on the type of utility. Are you a trades person? Then perhaps a larger van is more appropriate such as a Ford Transporter, or smaller versions such as a Renault Kangoo. Or if you need to transport many people, perhaps a mini-van like a Mercedes Vito, or a bus is what you need to fulfil that utility. There is certainly a vehicle for every type of utility. An SUV does not fulfil any sensible and rational utility. Let’s look at other aspects of a potential purpose that could be.

If the purpose of the vehicle is to transport one or two people in the city, then get a car with a small footprint that is manoeuvrable so you can get easily through narrow lanes and you do not need much parking space either. SUVs consume more space and volume in a city environment to the nuisance of all other traffic participants. As a consequence, for example, these SUVs parked in European town’s narrow spaces make it often impossible for other people to get in and out of their car. Worse, since their doors are higher, they tend to dent smaller cars. By using smaller, more appropriate vehicles, the energy consumption per person for both production and operation will be significantly smaller. It remains questionable what the purpose of the strong and sturdy design of an SUV is when it is mostly used on normal roads and cities. Nobody would walk around in town in full mountain gear with heavy boots, would you?

Should one need a lot of interior space for children and all the stuff that goes with having children, then get a car such as a Renault Scenic, Vauxhaul Meriva, Toyota Verso; if your family is larger why not get something like but not limited to a Seat Alhambra or a Ford Galaxy. They offer space without too much additional mass and with a decent drag coefficient; family cars are like a Tardis on wheels being unexpectedly spacious on the inside. I am always surprised that SUVs are internally quite small despite the bulky outside; an inverse Tardis effect. Most of an SUVs volume is consumed by the chassis, leaving less space to passengers. To me they look sometimes like cartoon characters with a large chest, wide neck and small, trapezoidal head with little space for the brain. They look strong and bold, but un-intelligent.

Then there is the sports aspect of a Sports and Utility Vehicle. If it is a sports car you are after, well, then treat yourself to a proper one. Despite the fact that a lot of energy is needed to produce and run nice sports cars, there is something intrinsically appealing about genuine sports cars. It may perhaps be the fascination of technology and the beauty of the design, which I can relate to as an engineer, e.g. a Jaguar E-Type or the newer F-Type. On the positive side of sports cars, it has to be said that usually not many miles are driven with them and they are operated for a long life time, in particular when they become vintage cars; they are share over a long period of time, so a good return on energy expenditure after all.

There is yet another angle to the “sports” aspects of an SUV, the idea of driving off-road as a sports activity. There may be something psychologically attractive in driving a vehicle through rough terrain, with big tyres and an appropriate suspension, four wheel drive with plenty of traction torque. All that instils perhaps the feeling of power and strength, of being a tough person. I grew up on a farm, so somewhat I can relate to that when driving a large 4x4 John Deer tractor though a field while pulling a plough; the tractor with its enormous engine torque literally ploughs through everything, being indifferent to any resistance, or at least until you loose a ploughshare. By extension, this tractor makes me feel stronger than I am. This aspect of feeling strong and indifferent to any resistance thrown in one’s way may be an appealing factor in the attraction to an SUV. It may tap into a deep, but mostly male desire.

However, there is no need to use a tractor or an SUV every day, let alone in a city. Where on UK or European roads, if I may ask, would an SUV be needed? Even pot holes do not justify SUV type drive trains, suspensions, large wheels and its larger road clearance. The only concession I would make is perhaps a Landrover Defender as a farm utility vehicle. When you live in the city, however, and fancy a rough ride, why not just hire such a vehicle for that purpose if this is what makes you feel happy as a sports experience. Then only few of these monsters would be needed and they would be contained in an appropriate area and terrain.

Vanitas vanitatum, omnia vanitas

All that being said, I think it is clear that there is no true utilitarian purpose for an SUV, there is no utility in an SUV, and the sports aspect is questionable. However, there is one important aspect, or perhaps you could say purpose of the SUV. It serves as an instrument to express purchasing power, or simply power, or perceived or aspired power, which all is an expression of vanity. Bluntly speaking they serve no purpose other than the vanity of the owner and driver. An SUV is a vanity vehicle.

Quite often, as cyclist I try to get a glimpse of SUV drivers and I found two major groups. There are those drivers who may indeed be wealthy and powerful; you can see in their facial expression, they look down on others, they feel above others and even sometimes above the law: no need to indicate, not need to give way. I have experienced that attitude as cyclist quite often. Then there are those who aspire to be that powerful and want to express that they have arrived, too. They possibly think, by buying and driving such a car they will gain power, or at least they get the feeling of being powerful. You often can perceive their expression of self-importance, smugness and self-content in their face, bordering to hubris. Perhaps it is just a symptom of our times of self-obsession and exaggerated individualism.

It takes a certain mindset to buy and drive a large SUV. It needs in my opinion the mindset of a bully to desire and drive an SUV. This is the reason why I tend to call them bully-wagons. They express a “Get out of my way” mentality. Many years ago my then three year old son asked me when he saw a particular SUV: “Papa, why does this car look so angry?”. I was surprised that a three year old already could read the expression that drives the mentality and by extension the design of these vehicle. I told him: “Perhaps because the driver wants to appear strong and indifferent to all he and his vehicle encounter on the road. It is, however, a sign of weakness”. Whether extremely large SUV, or a small vehicle with the appearance of an SUV, some people are attracted to that SUV-ness, the bold and brash looks. They feel strong and invincible in such a vehicle.

Lastly, often SUV drivers will advance practical reasons such as being seated a bit higher than the rest of the road participants. In the same vein they argue that they feel a bit safer, being in a larger and heavier vehicle. What they may not realise is that they are inadvertently entering an arms race; where do you stop, a monster truck, a tank? What they are talking about is only relative safety for the person inside that does not address the issue of protecting all people involved in the road system. By virtue of being larger and higher, an SUV is rather likely to endanger other traffic participants. Even worse, converting traditional cars by putting a larger chassis underneath may even make the vehicle less safe as the centre of mass is higher, only deteriorating the cornering behaviour and making the car more accident prone.

Please Refrain from Buying SUVs

The bottom line is this. The world appears to be afflicted with a contagious disease: S-U-V-ities. Please, stop buying this kind of vehicle and stop promoting it; think of the evolution of mankind in terms of climate change, energy and resource usage, but also in terms of respect for others and being mindful. Of course, we cannot forbid people to buy what they want and we cannot impose taxes on them to make them more expensive. This approach would backfire as it makes the vehicles even more desirable for the kind of people who want to demonstrate their purchasing power. We should work on making these vehicles less desirable by exposing their weaknesses, the fact that they are the manifestation of mankind’s vices, the materialisation of all the wrong values in our society. People should be feeling ashamed buying and driving those energy gobblers.

After all, the world would do better with fewer and more energy efficient cars, and most importantly by using shared forms of transportation including, in due course, autonomous forms of transport. And even if you might mean well, do not even consider an electric SUV; it still suffers from the same issues pointed out above and would be the irony for all efforts to combat climate change. If you really must buy a car, at least get yourself a decent car, by which I mean carried by the concept of decency and modesty.

References

(1) https://www.cars.com/research/compare/

(2) David MacKay, “Sustainable Energy — Without the Hot Air”, Green Books, 2009, https://www.withouthotair.com/c3/page_29.shtml.

(3) Gianpiero Mastinu (Editor) and Manfred Ploechl (Editor): “Road and Off-Road Vehicle System Dynamics Handbook”, CRC Press, 2014.

(4) Mattias Hjort, Mattias Haraldsson, Jan M. Jansen: Road wear from Heavy Vehicles — an overview, Report nr. 08/2008, NVF committee Vehicles and Transports, 2008.

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Peter Wurmsdobler

Peter Wurmsdobler

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Works on the technological foundations of autonomous vehicles at Five, UK. Interested in personal mobility, renewable energy and regenerative agriculture.