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2017 Lexus RX 450h Hybrid: Real-World Gas Mileage

2017_lexus_RX450h_JB.jpg 2017 Lexus RX 450h; | Cars.com photo by Joe Bruzek

CARS.COM — Increasingly fuel-efficient SUVs are partly contributing to slumping sedan sales of late, but Lexus is no stranger to SUVs with impressive gas mileage a hybrid version of its RX luxury SUV has been in its lineup for more than a decade. The 2017 Lexus RX 450h sips gas more like an entry-level compact SUV than a roomy mid-sized luxury utility vehicle, with an EPA rating of 31/28/30 mpg city/highway/combined. We jogged through the Chicagoland area on our 120-mile gas mileage test loop to test the RX 450h’s mileage in the real world.

Related: Our View: Lexus RX 450h

After 119.8 miles, we got 35.7 mpg — mighty impressive considering it’s 5.7 mpg higher than the combined rating. We expected fuel economy to climb in traffic, where the electrified hybrid system operates at low speeds without using the gasoline V-6, and sink on the highway portion, where the V-6 is buzzing away at 55 mph. That’s mostly how it played out, with the fuel economy increasing as average speed decreased.

Our number is an average of the onboard trip computer, which spit out 35.6 mpg, and the calculated fill-up gas mileage that came to 35.8 mpg, dividing the 119.8 miles by the 3.347 gallons of premium fuel the RX required after completing the trip. Our average speed of 32 mph included a mix of interstates, suburban highways and bumper-to-bumper Chicago rush-hour traffic.

2017_lexus_RX450h_prem_JB.jpg 2017 Lexus RX 450h; | Cars.com photo by Joe Bruzek

Procedure for our mileage tests included driving the RX 450h in its default driving mode and avoiding the available electric-only or economy modes. Ambient temperature was 55 degrees Fahrenheit, all windows were closed, tire pressure was at the automaker’s recommendation and the air conditioning was set at a constant temperature.

While no doubt impressively gas-friendly, the RX 450h isn’t the most engaging SUV to drive, which you wouldn’t expect looking at its wild styling. The hybrid system is a bit pedestrian and not quite up to the luxurious refinement of the RX 350’s V-6. Still, it’s hard to find an SUV the size of the RX that returns the fuel economy of a much smaller vehicle. Those looking for a gas-friendly SUV with a bit more spring in its step might want to check out the smaller 2017 Jaguar F-Pace 20d, an EPA-rated 29-mpg-combined diesel SUV that stunned us with its the highway frugalness.

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