Back in 2010, we asked why so few of today's cars were among the most fuel efficient ever.

Look down the list of the most fuel-efficient vehicles sold in the U.S, and only a small handful had been built in the previous decade--cars such as the familiar Prius, and the all-too-brief but brilliant first-generation Honda Insight hybrid.

Well, that's now changing, and in the last few years, modern cars have started fighting back. Gas mileage is rising and technology is finally overcoming the hindrance of extra weight, equipment and safety--all factors that eroded the benefits of improved aerodynamics and engine technology.

Modern cars now dominate

When we last looked at efficient cars from the last few decades, only a handful of modern cars made it into the list.

Topping that list back then, and still doing so today, was Honda's original 1999 to 2006 Insight. Even today, its ingredients are just about perfect for an economical car: Ultra light weight, a small, aerodynamic body, a small, efficient gasoline engine and the assistance and regeneration of an electric motor.

It was compromised no doubt--only two seats, and modest performance--but as a vehicle designed for efficiency, Honda had got the recipe spot-on. In reality, it's taken more than a decade to match with cars like Volkswagen's XL1--not yet on sale and using plug-in technology, and therefore not included in our list.

Second place has changed though, thanks to the introduction of another Prius--the Toyota Prius C. Knocking its larger counterpart from second place, the Prius C manages 53 mpg in the city and 46 on the highway, for a 50 mpg combined figure.

The rest of the top ten reads as follows:

  • 2013 Toyota Prius - 51 city, 48 highway, 50 combined
  • 1986 Chevrolet Sprint ER - 44 city, 53 highway, 48 combined
  • 2013 Ford C-Max Hybrid - 47 city, 47 highway, 47 combined
  • 2013 Ford Fusion Hybrid - 47 city, 47 highway, 47 combined
  • 1994 Geo Metro XFI - 43 city, 52 highway, 47 combined
  • 2009 Toyota Prius - 48 city, 45 highway, 46 combined
  • 1987 Honda Civic CRX HF - 42 city, 51 highway, 46 combined
  • 2013 Lincoln MKZ Hybrid - 45 city, 45 highway, 45 combined

If you're keeping count, that's an impressive seven cars in the top ten sold during the past decade. They've raised the game too--2010's point of entry into the top ten was a mere 41 mpg combined, 4 mpg lower than the least efficient entrant today.

2000 Honda Insight

2000 Honda Insight

So what's changed?

In just three years, automakers have made a real push for fuel efficiency. This can be seen in average gas mileage rising month on month, but even those right at the top have made big gains in efficiency.

Last time, our list mainly comprised small, light-weight cars, the occasional hybrid thrown in for good measure. There's little small and light about either of Ford's current hybrids or the Lincoln MKZ (itself based on the Fusion Hybrid), yet they're still right up there for on-paper economy.

It appears we've now reached a point where hybrid technology is advanced enough to overcome those issues associated with weight and performance, meaning economy is no longer the preserve of the tiny, tinny and lightweight.

Lightness still has an effect of course. The Prius C, Toyota's smallest hybrid, hasn't leapt high onto the list for no reason. Its relatively small proportions and light weight help it attain that 53 mpg city figure, higher than any other vehicle in the top ten.

And it's also why every non-modern vehicle in the list is where it is. The Chevy Sprint, Geo Metro and Honda CRX were made at a time when safety and equipment were minimal. As we noted back in 2010, you couldn't sell such a vehicle today--though the original Insight and Prius C could be considered modern equivalents.

2014 Mitsubishi Mirage

2014 Mitsubishi Mirage

Old-school still rules?

Even more similar to those 80s and 90s gas mileage stars is the recently-unveiled Mitsubishi Mirage.

It's not the most appealing vehicle we've ever seen (or driven), but its gas mileage tops that of any other non-hybrid small car on the market. Unlike many automakers glorifying a 40 mpg highway rating, the Mirage can do 40 mpg combined with a continuously-variable transmission--with 44 mpg highway and 37 mpg city figures to back it up.

It's small, it's light (around 1,863 pounds in European specification) and it's aerodynamic, with a coefficient of drag of 0.28.

The Mirage is also likely to be inexpensive, something buyers enjoyed with those 80s subcompacts and enjoy less about today's hybrids.

Conclusions

So what can we learn from all this?

Firstly, that small, light and inexpensive vehicles still rule when it comes to budget motoring. If you're prepared to live without today's levels of comfort, convenience and performance, you can save a heck of a lot of money on purchase and gas by picking up a suitable 80s or 90s car.

Secondly, that automakers have made huge advances in efficiency in the space of only a few years. New buyers are no longer limited to choosing just a select handful of modern vehicles capable of high gas mileage--everything from subcompact hatchbacks to midsize luxury vehicles appear among the most efficient vehicles ever sold in the U.S.

And that's before you even look at plug-in hybrids, range-extended vehicles and battery electric cars.

Finally, the concept of the small, lightweight gas-saver may not yet be dead. Sure, hybrids now top the list, but with cars like the Mitsubishi Mirage--and doubtless others to follow--there's still room for something small, light and simple if you want to save some gas.

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