Why on earth would anyone but a farmer want to own a four-wheel-drive truck instead of a normal car?
Seeing what such a vehicle did to this country's top rally driver, Possum Bourne, should be a wake-up call to our parliamentarians.
Big, heavy four-wheel drives are sold thanks to an advertising illusion.
The Washington Post recently took it to extremes when one of its journalists wrote that the Hummer H2, the biggest, ugliest SUV on the market, "is what Jesus would drive".
Its size was justified, he said, because "if you are a missionary," you could use a Hummer "to bring food and medical supplies" to the poor.
The reality is that most of these vehicles are never going to get anywhere near the Himalayas, darkest Peru or African mission stations, but will spend their time running children to school.
The only reason they are bought is because they are a fashion trend, as are low-waist jeans and navel piercings. The trend began in the US (where else), where Jeep was exempted from anti-smog regulations as their then owners were in financial trouble. To this day, every sports utility vehicle, as four-wheel drives are known in the US, sold is allowed to emit substantially more smog-forming pollutants than cars.
Like many American trends, it spread like a virus throughout the world. It is sadly ironic that a Jeep, the vehicle that started this whole process, was responsible for the death of Bourne near Queenstown last year.
In the US, SUVs are said to cause an avoidable 2000 deaths a year in cars struck by such vehicles.
Four-wheel drive owners may hold the view that if anyone has to die, it's preferable it be the other person.
In a frontal crash, the high noses of four-wheel drives tend to ride up over the sloping engine compartments of regular cars, resulting in the bigger vehicle sitting atop the car and crushing its occupants.
But SUVs kill a lot of their own occupants, too, because of their high centre of gravity. Again, in the US, about 1000 people die needlessly in rollovers each year because they are in SUVs instead of cars.
Such vehicles also burn much more fuel than cars. So the question persists, why on earth would anyone drive one?
New York Times journalist Keith Bradsher says market research about SUV buyers is that "they tend to be people who are insecure and vain and often lack confidence in their driving skills".
Mr Bradsher quotes US research that shows that the stronger the desire to own an SUV for supermarket shopping, then the greater the "Peter Pan Syndrome". Apparently this signals boredom with suburban married bliss, and a latent desire to be single again.
Last year Australian former Prime Minister Paul Keating said they should be taxed off the roads, and recently the Lord Mayor of London made similar threats, describing UK four-wheel drive owners as idiots.
This might be overstating the point, but the reasons for not owning such a vehicle do seem to far outweight the pluses.
So what's the solution? There are so many of the vehicles on the roads it would be political suicide to ban them and a massive tax increase would also be politically unacceptable.
New Plymouth engineer John de Bueger has come up with an idea that is rather elegant - he suggests applying the golden truth inherent in Newton's second law of motion.
In layman's terms: The heavier the vehicle that hits you, the bigger the bang, and this is proportionately greater depending on the impact velocity squared.
In simple terms, doubling the speed increases potential damage by a factor of four.
Therefore it follows, de Bueger says, that those in four-wheel drives caught over the limit, be it speed or alcohol, should have their fines proportionately increased, in accordance with Newton's second law.
What a sensible idea.