23 MPG combined isn’t going to win any awards for lower fuel costs, and it isn’t the reason someone buys a 2015 Buick Regal with the 2.4L four-cylinder. This generation Regal occupies a peculiar space: a near-luxury sedan aimed at buyers who prioritize comfort and understated elegance over outright sportiness, but who also want something more engaging than a traditional American sedan. Fuel economy is less important than the overall driving experience, the quiet cabin, and that Buick badge on the hood. It’s a conscious trade-off.

City and highway performance

The EPA estimates of 19 MPG in the city and 30 MPG on the highway paint a clearer picture of where this Regal performs best. The 19 MPG city figure reflects the extra effort the engine and six-speed automatic transmission need to get all 3,600 pounds of Regal moving from a stop. Expect a noticeable dip in fuel economy during stop-and-go commutes. On the open road, the 30 MPG figure is achievable, even with the cruise control set a bit above the speed limit. The Regal’s comfortable ride and quiet cabin make it well-suited to long highway drives, allowing it to stretch its fuel significantly further.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2015 Buick Regal 2.4L at $1,900. This figure is based on driving 15,000 miles per year, with 45% of those miles driven in the city and 55% on the highway, assuming national average fuel prices. Individual fuel costs will vary based on driving habits, local fuel prices, and the type of fuel used. If you drive significantly more or less than 15,000 miles per year, or if fuel prices in your area are far from average, expect a different annual fuel expenditure.

Real-world expectations

While the EPA provides a standardized benchmark, real-world fuel economy is rarely identical to the official figures. Drivers find that achieving the EPA’s 30 MPG highway rating is usually possible, particularly on long trips at steady speeds. The 19 MPG city rating can be harder to replicate, depending heavily on traffic conditions and driving style. Expect a combined MPG figure closer to 21 or 22 MPG in mixed driving. Aggressive acceleration or frequent short trips will drag that number down further, while a more relaxed driving style and longer trips will bring it closer to the EPA’s 23 MPG rating. Remember, those opting for the turbo engine will see even more variance depending on use case and driving style. For REGAL MPG across all years, you can see how this engine compares.

How it compares

The 2015 Regal’s fuel economy sits in the middle of its competitive set. A similarly equipped Acura TLX with a 2.4L engine and eight-speed dual-clutch transmission achieves a slightly better 28 MPG combined. A turbocharged Ford Fusion EcoBoost from the same year might get closer to 25 MPG combined if driven carefully. The all-wheel-drive variants of many competitors take a fuel economy hit. The Lexus ES 350 boasts similar levels of comfort and refinement to the Buick, but its larger V6 engine delivers around 24 MPG combined. The Regal’s core buyer is likely aware of these differences but prioritizes the Buick’s specific blend of attributes, where luxury and cabin noise take precedence over best-in-class MPG. These buyers are less concerned with squeezing every last mile from a gallon, they’re looking for a comfortable and refined driving experience at a reasonable price that balances luxury against MPG. It’s possible to see all Buick fuel economy data in one spot.

Tips to maximize efficiency

Avoid aggressive acceleration and braking. The Regal’s six-speed automatic is programmed to upshift early and often, so let it do its job. Gentle acceleration allows the transmission to keep the engine in its most efficient range. Rapid acceleration and hard braking dramatically reduce fuel economy.

Maintain proper tire inflation. Under-inflated tires increase rolling resistance, forcing the engine to work harder and consume more fuel. Check your tires regularly and inflate them to the recommended pressure listed on the sticker inside the driver’s side doorframe.

Minimize idling. Idling consumes fuel without covering any distance. If you anticipate stopping for more than a minute, turn off the engine. Modern cars are designed to restart quickly and efficiently, making this a simple way to save fuel, especially during city driving.

Use cruise control on the highway. Cruise control maintains a consistent speed, minimizing unnecessary acceleration and deceleration. This helps to optimize fuel economy on long highway drives. However, be mindful of using cruise control in hilly terrain, as the car may aggressively downshift to maintain speed, negating some of the fuel-saving benefits. But when on mostly flat terrain, cruise control can provide a bump in MPG.