The auto industry gets plenty of attention for its environmental impact, but it's clear to see that fuel efficiency has made huge strides even in the last five years.
It could be even better, though.
Ultimately, a carmaker has to sell cars to survive--and it does that by creating products that people want, continually refining, and adding "more" of everything.
Below, we look at five things automakers will never do, which could really push efficiency to new levels.
1. Increase noise
Electric cars may put into context how much noise regular vehicles produce, but compared to their predecessors, all cars are pretty quiet.
That particularly applies at speed, where wind roar, tire noise and engine drone have all been minimized, to the point where even smaller cars can comfortably cover large distances. And they do so at speed--speeds which reduce gas mileage.
It wouldn't be popular, but removing sound-deadening material and introducing a bit more noise would encourage people to travel a little slower, where the sounds were more bearable--and all other things being equal, they'd save more gas at those lower speeds.
It would be incredibly simple and cheap to implement--but people like refinement, so don't expect cars to get noisier any time soon.
2. Reduce standard equipment
Even subcompacts come with navigation, climate control and leather seats these days, all of which add quite a bit of weight to the average car. In fact, they add loads. That's before you consider the electrical drain too, requiring an alternator to leech power from the engine in order to keep your radio tuned in.
We all know that reducing weight increases performance, improves handling and reduces fuel consumption--but how many people would really be prepared to sacrifice their creature comforts for a few extra mpg?
3. Radical aerodynamics
Remember the Aptera Type 2e? The teardrop-shaped, three-wheel pod was designed to have incredibly low aero drag.
Of course, it also looked a bit weird, which is more than enough to put off the majority of drivers. Even less extreme shapes, like the first-generation Honda Insight, are an acquired taste.
2000 Honda Insight
Radical aero can work wonders for improving gas mileage, but it comes with compromizes. Looks, for one, and practicality for another--the subcompact-sized Insight was only a two-seater, a side-effect of making the car both aerodynamic and small.
Normal cars could get more radical to raise MPG--but for many, the cars may lack usability.
4. Tandem seating
How do you take aero another step further? By making the car as cigar-like and streamlined as possible.
We've actually seen this with several recent concepts, such as the Audi Urban Concepts and the Volkswagen Nils. The former had two, offset-tandem seats, the latter, only a single seat.
There's no doubt that such a product would suit a great many people--but again, customers like utility. A single-seat car may be great for five days of the week, and utterly useless for the other two. You may be wasting 3 or 4 seats on most journeys, but for many that's preferable to buying another car to cover your remaining tasks.
5. Delete gas-guzzling engines from the range
Want to meet those CAFE requirements a few years early?
Logically, the best thing to do would just be to stop making those big V-6 and V-8 engines entirely.
Except carmakers will never do that, as it would be commercial suicide. No carmaker will take the first step towards deleting models like that, lest their customers simply go elsewhere.
And if a company loses money from removing the products people want, then they certainly won't be producing any high-efficiency vehicles either...