Sports cars, muscle cars, and supercars are great to drive. However, many owners of these machines don't drive them every day, especially if there's a commute to consider. For the daily grind, most folks are going to spring for something that sips fuel and is reasonably comfortable, with few extra frills. This is especially true for those with a gargantuan commute who may need to really watch their wallets at the pump.In 2016, Mazda was ahead of the game when it came to a midsize, non-hybrid sedan with excellent fuel economy. The model in question is the 6, and during that model year, which earned the title of the most fuel-efficient midsize sedan that's not a hybrid. The 2016 Mazda 6 is well-sorted for safety, and its current average used price is incredibly affordable for most. In short, this four-door seems to shape up as a well-rounded commuter car. A Clever Powertrain Mazda When it comes to fuel efficiency, the bulk of the work falls to the vehicle's engine. Nestled beneath the 2016 Mazda 6's hood is a rather underwhelming 2.5-liter inline-four engine from the Japanese automaker's Skyactiv family of powerplants. More specifically, the mill is known internally as "PY-VPS" and entered production in 2013. While it doesn't boast many fancy, go-faster upgrades, the unit does house a unique, efficiency-boosting piece of technology.It's called the i-ELOOP system. Much like a conventional hybrid, the i-ELOOP tech uses regenerative braking to send power back into the car. The assist works via the car's alternator, which receives electricity generated by the car's braking system. Once the alternator has the aforementioned energy, it's stored in a small capacitor that works alongside an Absorbent Glass Mat (AGM) battery or a Q85 Enhanced Flooded Battery (EFB) battery. Then the capacitor can discharge the stored energy to power accessories, such as the car's lighting, HVAC system, and electric power steering.According to Mazda, the i-ELOOP system increases the 2016 Mazda 6's fuel efficiency by up to 5%. It works in conjunction with a set of front grille shutters that activate at highway speeds and has three settings: 0 degrees, 78 degrees, and 90 degrees. The system wasn't offered on every 2016 Mazda 6 trim, only the top-spec Grand Touring grade when optioned with the Technology Package.Take a look at how the 2016 Mazda 6's fuel economy stacks up to some of its competitors: What The 2016 Mazda 6 Grand Touring Has To Offer MazdaSeeing as the fuel-efficient i-ELOOP system is only offered on the top-spec Grand Touring trim, the rest of the model comes standard with plenty of luxury amenities. Interior & Tech MazdaAs standard, the Grand Touring models have leather-trimmed seats with heated front chairs. An eight-way power driver seat and a six-way adjustable passenger seat are also among the amenities. Dual-zone climate control is baked right in. Sitting center-stage is a 7.0-inch touchscreen infotainment system that uses Mazda's Mazda Connect software. A premium Bose 11-speaker sound system and voice-activated navigation are standard, too. Exterior MazdaUnlike the lesser trims, the Sport and Touring models, the Grand Touring grade receives a full LED exterior lighting setup, including its headlights. It also boasts an adaptive front lighting system, which means it can adjust its headlight position by up to 15 degrees in response to steering input. A power-sliding moonroof is standard, along with a small trunk spoiler. Its wing mirrors feature LED turn signal indicators and a heating function. Safety Mazda Apart from the standard safety kit found on virtually all modern cars, like three-point seatbelts and side-curtain airbags, the Grand Touring-spec 2016 Mazda 6 also comes with a slew of Active Safety features. In addition to things like anti-lock brakes and Dynamic Stability Control, it also boasts blind-spot monitoring and hill-start assist. Folks could also opt for additional safety features, such as Smart Brake Support with Collision Warning and a lane departure warning system. More On Its Mechanical Make-Up Mazda The sole engine offered on the 2016 Mazda 6 is the 2.5-liter inline-four, either with or without the i-ELOOP system. Backing up either iteration of the 2.5-liter engine was a six-speed automatic transmission produced by Mazda. A six-speed manual was also on offer, although Mazda 6 Grand Touring models could not be optioned with the stick shift. Front-wheel drive is the sole drivetrain option, as well.As for its suspension, Mazda used a MacPherson strut setup at the front and a multi-link setup at the rear. According to Mazda, the 2016 6's suspension was designed to be both comfortable and sporty, with features such as anti-lift geometry that help keep the car planted through hard cornering. However, to bolster comfort, the 2016 Mazda 6 reportedly uses special body and motor mount bushings, called "optimized bushings," to reduce cabin vibration. How Much You'll Pay MazdaIf all this sounds good to you, and you're interested in picking one up for yourself, you won't need to empty your savings to get one. According to Kelley Blue Book, the 2016 Mazda 6 in Grand Touring trim currently has an average used price of $11,880. The CarBuzz Marketplace (below) shows an average of $12,205 for this trim level. For context, a 2016 Mazda 6 carries an overall average used price of $10,498 across all grades. The 2016 Mazda 6's Economical Runner-Up NissanIf you're not keen on jumping into a car with a slightly odd regenerative braking system, fear not, because the 2016 Nissan Altima S comes in second place in the non-hybrid midsize sedan fuel economy shootout. Like the Mazda, the Nissan came with a 2.5-liter inline-four-cylinder engine, albeit without the fancy i-ELOOP system, of course. Instead of the 32 mpg that the Mazda offered, the 2.5-liter-equipped Altima boasted a combined rating of 31 mpg.One of the largest Achilles heels of the 2016 Altima was its use of CVTs, which, as many of you may know, Nissan had quite a few issues with throughout the beginning and middle of the 2010s. While advantageous for fuel efficiency, Nissan's CVTs were prone to problems. Also like the Mazda, the Altima came with a MacPherson strut suspension up front and a multi-link configuration at the back. In total, the Altima offered several trim levels, including the 2.5, 2.5 S, 2.5 SR, 2.5 SV, 2.5 SL, 3.5 SR, and 3.5 SL. The latter two "3.5" grades came with a 3.5-liter V6.If the Altima is more your speed, prepare to pay around $13,715 for an example in average condition with average miles.