How Consumer Reports Tests Cars

The acceleration tests are conducted on a smooth, flat pavement straightaway at the track. The tested car is rigged with a precise GPS-based device that’s hooked to a data-logging computer and a display that’s mounted on the windshield. This equipment creates precise records of time, speed, and distance. We use it to measure sprints from 0 to 30 mph and 0 to 60 mph, and for quarter-mile runs. All times are measured from a standing start. Good acceleration is more than the fun factor. It’s also vital for executing safe highway merges and can potentially play a role in some accident-avoidance situations.

ACC is an advanced version of traditional cruise control that automatically adjusts your car’s speed to keep a driver-selected distance from the vehicle ahead. We test every vehicle equipped with ACC to evaluate how comfortably and effectively each system manages speed and following distance.

Our 1.5-mile ADAS (advanced driver assistance systems) loop was designed according to current Department of Transportation specifications for lane width, lane markings, and road curvature. We use it to safely test advanced driver assistance systems with challenging features such as curves, split lanes, merging lanes, exit ramps, and intersections. (See a tour of the ADAS loop.)

In addition, we’ve applied lane markings on our main track to see how well some ADAS features react in real-world driving scenarios, such as when a car drifts out of its lane.

Good braking performance is a vital factor in a car’s accident-avoiding capability. Our automotive engineers conduct a series of brake tests from 60 mph to a standstill on wet and dry pavement to measure stopping distances. The tested car is rigged with a precision GPS-based device. We also judge brake-pedal modulation, which, in simple terms, means how easy it is to come to a smooth stop on the road.

Engineers trained in ergonomics/human factors evaluate a car’s controls and displays, judging how easy it is to interact with the various vehicle functions such as audio, climate, phone, and all the switches and instruments. Every auto-test staff member logs comments drawn from months of living with the cars and driving them every day for commuting, trips, and errands. The more intuitive and user-friendly the controls are, the better, and the higher score they receive.

Active driving assistance systems that are capable of automating acceleration, braking, and steering (which is the combination of adaptive cruise control and lane centering assistance) can reduce driving stress. But they should be paired with camera-based monitoring to ensure the driver is looking at the road. For now, hands-free is a misnomer. We prefer to think of it as collaborative driving. 

Staff members of different sizes, ages, and genders judge how easy it is to get comfortably situated behind the steering wheel. They gauge whether they can see out well and reach all controls and pedals without straining or developing premature fatigue. They also get into and out of every seat, and note the ease of entry and exit. Seat comfort is judged on comfort and support.

To provide the most useful, up-to-date advice for today’s car buyers, we’ve been purchasing more electric and plug-in hybrid electric vehicles for our test fleet and expanded our Level 2 charging stations to a total of 28. This enables us to keep cars charged up for tests like our highway-range check.

The Environmental Protection Agency provides only a combined city/highway range rating for EVs. We think highway range is a key concern for consumers, so we base our range score on our own EV-specific highway-range test. We drive at a constant 70 mph on a 100-mile loop on public roads (in dry summer weather) until the EV can no longer move under its own power to gauge how far it could go before it needs recharging on a long trip. The EV range score is initially based on the EPA combined range rating. Once we evaluate a model’s highway range, we update the score using our findings. These findings, and many more EV- and PHEV-specific test results, are available on the car model pages. With this test, buyers will know how far they can drive on a road trip.

Our team also assesses ease of charging and the helpfulness of apps and route planning (with EV charging factored in), and tracks charging rates. 

Crucial emergency-driving tests include an avoidance maneuver and a series of at-the-limit cornering assessments around a handling course—a snaking track loop. The avoidance maneuver is a “path-following test” in which the driver pilots the car down a lane marked off by traffic cones with a quick left-right-left steering sequence. That simulates swerving to avoid an obstacle in the road, then returning to the original lane to avoid oncoming traffic. Our testers thread the car through the course, without throttle or brakes, at ever-higher speeds until it can’t get through without hitting any cones. We use a laser-beam-based device to record and monitor entry speed. When testing at-the-limit handling, drivers push the car to and beyond its cornering capabilities to simulate entering a corner too quickly. Test engineers evaluate how controllable, secure, and forgiving the car is through the maneuver.

Our 3,500-foot curvy road course helps us assess how well each vehicle negotiates corners. We push vehicles, evaluating the suspension and steering specifically, but this gives us insights into the powertrain and brakes, as well. Markings on every curve help testers drive each car through the same path.

Experienced engineers evaluate every test vehicle’s interior qualities. They want to see that the trim pieces have minimal gaps and properly align with one another, and that the texture of adjacent panels matches. The testers also judge the tactile quality of the plastics, leather, fabrics, and switchgear, the parts that owners interact with on a daily basis. They look for quality in sewn seams and for ill-trimmed plastic mold flash, rough edges, and hard, hollow plastic surfaces. They also pay attention to the way nooks and cubbies are finished inside and out; whether cup holders are sturdy, flimsy, or ill-placed; and whether compartment doors open and shut smoothly.

We perform our own fuel-economy tests, independent of the government’s often-quoted EPA figures and the manufacturers’ claims. Using a precise fuel-flow measuring device spliced into the fuel line, we run two separate circuits. One is on a public highway at a steady 65 mph. That course is run in both directions to counteract any terrain and wind effects. A second test is a simulated urban/suburban driving route done at our track. It consists of predetermined acceleration and deceleration rates, as well as idle time. Consumer Reports’ overall fuel-economy numbers on rated vehicles are derived from those fuel-consumption tests. Plug-in hybrids are tested with the EV-range depleted, to determine the baseline fuel economy when the vehicle is not charged.

Some semi-autonomous safety and convenience systems, such as lane centering assistance, lane departure warning, and lane keeping assistance, use onboard cameras that “see” the road. For these systems to work effectively, they need to assess a complex variety of lines on the road. We use our curvy ADAS loop and lane markings along the main straightaway of our track to evaluate how different systems interpret common roadway situations in a safe, controlled environment.

We evaluate and measure noise while the car is driven over various pavements, including specially built concrete slabs at our track. Complementing those findings is a noise evaluation conducted by our test engineers on local public roads. They note engine, road, tire, and wind noise and judge the level and quality of the noises, be they raucous or pleasant, annoying or exhilarating.

We check off-road capabilities for vehicles made for or advertised for off-road use. SUVs or pickups with a traditional four-wheel-drive system that includes low-range gearing or some equivalent are put to the test on varying terrain, including ascending our infamous rock hill. We evaluate the vehicle’s 4WD system and the driver’s ability to modulate the throttle, something vital for climbing over tricky obstacles. We also judge ground clearance, axle articulation, and, of course, traction. (Learn how it works: FWD vs. RWD vs. AWD vs. 4WD.)

We evaluate how easily child seats fit into each vehicle, along with how well rear occupant alert and rear belt minder systems perform (if equipped in the vehicle). Rear occupant alerts can help prevent children and pets from being unintentionally left behind in a hot or cold vehicle, while rear belt minders prompt rear passengers to buckle up and alert the driver if they unbuckle during the trip. We also look for the presence of advanced seat belt technology or airbags in the back seat.

Separately, we also test car seats, from front infant seats to boosters. We have ratings on over 100 car-seat models. (See our car seat buying guide and ratings.)

An overly stiff or uncontrolled ride can detract from the driving experience. Our engineers judge ride comfort on a 30-mile loop at predetermined speeds on a course that includes a variety of roads containing bumps, ruts, undulations, and a typical highway section. They note whether the suspension absorbs and isolates appropriately. They determine whether the ride is stiff, plush, choppy, tender, or floaty, and how well the car copes with pavement flaws. The engineers are attuned to adverse ride motions such as side-to-side rocking and fore-and-aft pitching. Comfort is the name of the game, as is the ability to provide a steady cruise regardless of the terrain. Cumulative experiences from commuting in cars and driving over rough surfaces at our track are also factored in.

Our testers judge routine handling primarily during a test we call a “one-day trip,” which consists of a 30-mile loop of local roads ranging from a smooth highway to secondary two-laners and rural twists and turns. A team of trained engineers assesses how well the car deals with curvy roads. That directly translates into the car’s agility and fun-to-drive qualities. The engineers note body control, such as body lean, and how steady the car remains over bumpy corners. They evaluate steering response to driver input and how well the car communicates feedback, mainly through the steering. The car’s turning circle is measured by technicians because this quality translates directly into ease of parking and maneuverability in tight spaces.

We don’t perform crash tests. Instead, we quote the government and Insurance Institute for Highway Safety crash-test results. Other aspects require a personal touch to evaluate. Our engineers assess safety belts, the most important safety device, in all seating positions, gauging how easy they are to reach and adjust, how they drape on different-sized occupants, and whether they incorporate features such as pretensioners that make them more effective. The engineers also check head restraints in all seats to ensure that they are tall enough and can be positioned properly to mitigate whiplash injuries. Another key check is to judge how conducive the vehicle is to the securing of child seats of various sizes.

Consumer Reports tests about 40 tire models every year—for cars, SUVs, and trucks—putting them through their paces in up to 12 tests. Most tests are conducted by an expert team at our 327-acre Auto Test Center in Connecticut. We also do braking on ice at a local rink, and an outside lab assesses tire rolling resistance, which affects fuel economy.

Track testing tells us how well tires stop and handle on dry and wet pavement, how well they resist hydroplaning, and how comfortably they ride on purposely made bumpy roads at our facility.

We also evaluate tread life by driving thousands of miles on a road course in western Texas and use that information, along with the price we paid for the tire, to estimate the cost per 100 miles to name the best tire values. (See the Top Pick Tires.)

Transmissions play a central role in delivering engine power to the wheels, and the characteristics of the transmission can greatly affect the overall driving experience. When evaluating transmissions, our engineers look for responsiveness, how quickly and appropriately the transmission selects its gears, and how seamlessly it upshifts and downshifts. They assess how in tune the transmission is with the throttle, grade, and driver’s inputs. For manual transmissions, the testers evaluate the shift action (how easy it is to move the shift lever through the shifter gate). The appropriateness of gear ratios is taken into account as well. The engineers also note the clutch action, looking for appropriate effort, pedal travel, and the point where the clutch engages. For electric vehicles, the performance, smoothness, and adjustability of the regenerative braking system is taken into account.

We examine each vehicle’s cargo capacity as part of our road-test score. For SUVs, wagons, and minivans, we use a special pipe box that expands until it just fits through the rear opening, giving us a true measurement of how large an object you can squeeze inside. For cars with a trunk, we check how many large suitcases, overnight duffel bags, and backpacks can fit. For pickup trucks, we measure the volume of the bed up to the top of the side rails. We also measure front trunks (frunks), underfloor cubbies, and other storage volumes where appropriate.

Editors/Writers: Keith Barry, Jeff S. Bartlett, Alex George, Jonathan Linkov, Mike Monticello, Stef Schrader.
Testing: Julian Barrera, Michael Bloch, Michael Crossen, Steve Elek, Jake Fisher, Gordon Gingras, John Ibbotson, Alex Knizek, Anita Lam, Maddie McCarty, Jonathan Moseley, Ryan Pszczolkowski, Mike Quincy, Mary Reed, Shawn Sinclair, Oliver Smith, Jennifer Stockburger, Emily A. Thomas, Marion Torres, Joe Veselak, John Williams, Avri Wyshogrod.
Facilities: Frank Chamberlain, Erik Dill, Mike Jascot, Steve Kuczynski.