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To help make backing safer, the RDX’s optional cross-path warning system uses wide-angle radar in the rear bumper to alert the driver to vehicles approaching from the side, helping the driver avoid collisions. The GLA doesn’t offer a cross-path warning system.
Compared to metal, the RDX’s plastic fuel tank can withstand harder, more intrusive impacts without leaking; this decreases the possibility of fire. The Mercedes GLA has a metal gas tank.
Both the RDX and the GLA have standard driver and passenger frontal airbags, front side-impact airbags, driver and front passenger knee airbags, side-impact head airbags, front seatbelt pretensioners, front-wheel drive, height adjustable front shoulder belts, four-wheel antilock brakes, traction control, electronic stability systems to prevent skidding, crash mitigating brakes, daytime running lights, rearview cameras, available all-wheel drive, blind spot warning systems and around view monitors.
The Acura RDX weighs 443 to 904 pounds more than the Mercedes GLA. The NHTSA advises that heavier vehicles are much safer in collisions than their significantly lighter counterparts.
For its top level performance in IIHS driver and passenger-side small overlap frontal, moderate overlap frontal, side impact, roof strength and head restraint tests, its standard vehicle-to-vehicle front crash prevention system, its standard vehicle-to-pedestrian front crash prevention system, and its standard headlight’s “Good” rating, the Insurance Institute for Highway Safety grants the RDX its highest rating: “Top Pick Plus” for 2020, a rating granted to only 30 vehicles tested by the IIHS. The GLA has not been tested, yet.
Acura’s powertrain warranty covers the RDX 2 years and 20,000 miles longer than Mercedes covers the GLA. Any repair needed on the engine, transmission, axles, joints or driveshafts is fully covered for 6 years or 70,000 miles. Coverage on the GLA ends after only 4 years or 50,000 miles.
The RDX’s 2.0 turbo 4-cylinder produces 64 more horsepower (272 vs. 208) and 22 lbs.-ft. more torque (280 vs. 258) than the GLA’s 2.0 turbo 4-cylinder.
As tested in Motor Trend the Acura RDX is faster than the Mercedes GLA:
Zero to 60 MPH
Speed in 1/4 Mile
To lower fuel costs and make buying fuel easier, the Acura RDX uses regular unleaded gasoline (premium recommended for maximum performance). The GLA requires premium, which can cost 20 to 55 cents more per gallon.
The RDX has 2.3 gallons more fuel capacity than the GLA (17.1 vs. 14.8 gallons), for longer range between fill-ups.
The RDX has a standard cap-less fueling system. The fuel filler is automatically opened when the fuel nozzle is inserted and automatically closed when it’s removed. This eliminates the need to unscrew and replace the cap and it reduces fuel evaporation, which causes pollution. The GLA doesn’t offer a cap-less fueling system.
In its Green Vehicle Guide, the U.S. Environmental Protection Agency (EPA) rates the Acura RDX higher (6 out of 10) than the Mercedes GLA (5). This means the RDX produces up to 6.9 pounds less smog-producing pollutants than the GLA every 15,000 miles.
A 10-speed automatic is standard on the Acura RDX, for better acceleration and lower engine speed on the highway. Only a seven-speed automatic is available for the GLA.
The RDX stops shorter than the GLA:
60 to 0 MPH
60 to 0 MPH (Wet)
For better traction, the RDX A-Spec’s tires are larger than the largest tires available on the GLA (255/40R20 vs. 235/50R18).
The RDX A-Spec’s tires provide better handling because they have a lower 40 series profile (height to width ratio) that provides a stiffer sidewall than the GLA’s optional 45 series tires.
For better ride, handling and brake cooling the RDX has standard 19-inch wheels. Smaller 18-inch wheels are standard on the GLA 250. The RDX A-Spec’s 20-inch wheels are larger than the 19-inch wheels optional on the GLA.
The RDX has a standard easy tire fill system. When inflating the tires, the vehicle’s integrated tire pressure sensors keep track of the pressure as the tires fill and tell the driver when the tires are inflated to the proper pressure. The GLA doesn’t offer vehicle monitored tire inflation.
The RDX AWD has a standard space-saver spare (not available on FWD/A-Spec) so you can replace a flat tire and drive to have the flat repaired or replaced. A spare tire isn’t available on the GLA; it requires you to depend on its run-flat tires, which limits mileage and speed before they are repaired. If a run-flat is damaged beyond repair by a road hazard your vehicle will have to be towed.
The RDX offers an optional driver-adjustable suspension system. It allows the driver to choose between an extra-supple ride, reducing fatigue on long trips, or a sport setting, which allows maximum control for tricky roads or off-road. The GLA’s suspension doesn’t offer adjustable shock absorbers.
For a smoother ride and more stable handling, the RDX’s wheelbase is 2 inches longer than on the GLA (108.3 inches vs. 106.3 inches).
For better handling and stability, the track (width between the wheels) on the RDX is 2.8 inches wider in the front and 3.3 inches wider in the rear than on the GLA.
For greater off-road capability the RDX has a 2.9 inches greater minimum ground clearance than the GLA (8.2 vs. 5.3 inches), allowing the RDX to travel over rougher terrain without being stopped or damaged.
The RDX uses computer-generated active noise cancellation to help remove annoying noise and vibration from the passenger compartment, especially at low frequencies. The GLA doesn’t offer active noise cancellation.
The RDX has 13 cubic feet more passenger volume than the GLA (104 vs. 91).
The RDX has 4.9 inches more front shoulder room, 4.5 inches more rear legroom and 3.5 inches more rear shoulder room than the GLA.
The RDX has a much larger cargo volume with its rear seat up than the GLA with its rear seat up (31.1 vs. 17.2 cubic feet). The RDX has a much larger cargo volume with its rear seat folded than the GLA with its rear seat folded (79.8 vs. 43.6 cubic feet).
Pressing a switch automatically lowers the RDX’s rear seats, to make changing between passengers and cargo easier. The GLA doesn’t offer automatic folding seats.
The RDX has a 1500 lbs. towing capacity. The GLA has no towing capacity.
The RDX uses gas struts to support the hood for easier service access. The GLA uses a prop rod to support its heavy hood. It takes two hands to open the hood and set the prop rod, the prop rod gets in the way during maintenance and service, and the prop rod could be knocked out, causing the heavy hood to fall on the person maintaining or servicing the car.
The RDX’s standard easy entry system glides the driver’s seat back, making it easier for the driver to get in and out. The GLA doesn’t offer an easy entry system.
The RDX Advance has a standard heads-up display that projects speed and navigation instruction readouts in front of the driver’s line of sight, allowing drivers to view information without diverting their eyes from the road. The GLA doesn’t offer a heads-up display.
The RDX’s power window, power lock, power mirror and cruise control switches are lit from behind, making them plainly visible and easier to operate at night. The GLA’s cruise control switches are unlit, making them difficult to find at night and operate safely.
To improve rear visibility by keeping the rear window clear, the RDX has a standard rear fixed intermittent wiper with a full on position. The rear wiper standard on the GLA only has an intermittent setting, so in a hard rain visibility isn’t as good.
Consumer Reports rated the RDX’s headlight performance “Good,” a higher rating than the GLA’s headlights, which were rated “Poor.”
While driving with high beams on, sensitive light sensors standard on the RDX detect other vehicles which could be blinded and automatically switch to low beams. The GLA doesn’t offer automatic dimming high beams.
To shield the driver and front passenger’s vision over a larger portion of the windshield and side windows, the RDX has standard extendable sun visors. The GLA doesn’t offer extendable visors.
When the RDX is put in reverse, both rearview mirrors tilt from their original position. This gives the driver a better view of the curb during parallel parking maneuvers. Shifting out of reverse puts the mirrors into their original positions. The GLA’s mirrors don’t automatically adjust for backing.
The RDX has standard heated front seats. Heated front seats cost extra on the GLA. The RDX Advance also has standard heated rear seats to keep those passengers extremely comfortable in the winter. Heated rear seats aren’t available in the GLA.
Optional air-conditioned seats in the RDX keep the driver and front passenger comfortable and take the sting out of hot seats in Summer. The GLA doesn’t offer air-conditioned seats.
On extremely cold winter days, the RDX’s optional heated steering wheel provides comfort, allowing the driver to steer safely and comfortably before the vehicle heater warms up. The GLA doesn’t offer a heated steering wheel.
Insurance will cost less for the RDX owner. The Complete Car Cost Guide estimates that insurance for the RDX will cost $1240 to $3465 less than the GLA over a five-year period.
According to The Car Book by Jack Gillis, the RDX is less expensive to operate than the GLA because typical repairs cost much less on the RDX than the GLA, including $485 less for a water pump, $324 less for a muffler, $202 less for a starter, $301 less for fuel injection, $16 less for a fuel pump, $167 less for front struts and $66 less for a timing belt/chain.
The Acura RDX outsold the Mercedes GLA by almost three to one during 2019.
© 1991-2018 Advanta-STAR Automotive Research. All rights reserved.
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