With Hyundai’s recent announcement that brake throttle override, which it calls brake pedal throttle override capability, is now standard on all 2012 Hyundai models effective with May production, consumers may be curious about what this safety technology is all about, as well as what other automakers have it and why.
In essence, brake-throttle override technology lets drivers control a vehicle’s speed and stop it in case of unintended acceleration. With Hyundai’s system, any brake pedal input by the driver has top priority in all driving situations and overrides any throttle inputs.
The 'why' is fairly straightforward. Brake-throttle override, although called by different names, is an additional “failsafe” safety technology. Beyond that, the National Highway Traffic Safety Administration (NHTSA) has issued a Notice of Proposed Rulemaking that is posted on its website (a 98-page PDF document). The proposed brake-throttle override regulations would go into effect September 1 two years from the date of the final rule.
The NHTSA’s proposed brake-throttle override regulation would set minimum requirements for existing as well as future light brake-throttle override systems. Based on the agency’s experience with them, existing systems will meet the proposed standard without modification. In the event that some systems do require changes to meet the proposed standard, the NHTSA believes those changes would be minimal.
Automakers that have it
Although the safety technology is currently making news, some automakers have offered it for years, while others are just now implementing it, either on select models or across their lineup.
BMW originated the electronic throttle pedal or “drive-by-wire” system in the 1988 BMW 750iL. By 1994 all BMW products sold in the United States had electronic throttle pedals. Since the very first system in 1988, every BMW Group electronic throttle system (including BMW, MINI and Rolls-Royce) has incorporated a brake override feature. The brake override feature is installed on all transmission versions: automatic, manual, sequential manual gearbox (SMG) and dual-clutch transmission (DCT).
See why our editors give the 2012 BMW 3 Series an overall 8.6 (out of 10) rating in this review.
Chrysler implemented brake override with production of the 2003 Ram 1500 with the 5.7-liter HEMI engine. The safety feature has been on all gasoline engines with Electronic Throttle Control (ETC) since that timeframe. The last production vehicle without ETC was the PT Cruiser, which ceased production in 2010.
Here’s how brake override works in all Chrysler, Dodge, Ram and Fiat vehicles built in the U.S.: The vehicles are calibrated such that the brake pedal must have been applied after the accelerator pedal to dial back throttle In addition, the duration of the accelerator-pedal application required to trigger this response is approximately two seconds.
Ford began migrating brake-throttle override, or Brake Over Accelerator (BOA), as the automaker calls it, in 2004 and the first product it appeared on was the 2005 Ford Escape Hybrid. By the end of calendar year 2010, it was implemented on nearly 100 percent of Ford and Lincoln light-duty models (excluding select low volume vehicles, such as certain trucks with a Cummins diesel engine). Owners of these trucks may not want BOA because they are backing up trailers or putting boats in the water, etc.
Brake Over Accelerator is a Ford-designed system. It is on manual and automatic transmission vehicles and operates the same. BOA is also on Ford hybrid and electric vehicles but operates a little bit differently than conventional powertrain vehicles. The system works the same way but the software calibration is a little different.
The BOA system monitors the accelerator pedal and the brake pedal position. If it senses brake pedal application and accelerator position not changing (for example, the accelerator is stuck or trapped), the electronic throttle is driven closed to idle position by the powertrain control module. As the throttle is driven closed, the brake force acts on the vehicle and it slows down—to a complete stop if the driver continues to apply the brakes.
Ford says that the system acts “very quickly.” When the brake is released, the system resumes normal operations, but the throttle is ramped back to the requested pedal position to allow a controllable acceleration. It also works in reverse.
At General Motors, the safety feature is known as “enhanced smart pedal technology,” and will be implemented globally on all its passenger cars with automatic transmissions and electronic throttle control by the end of 2012.
Also known as brake override, the change involves modifying existing electronic controls to reduce power to the engine in cases where the brake and accelerator pedal are being simultaneously depressed.
General Motors says that brake override is an additional safeguard to the braking performance standard GM has had for several years, applicable to all cars, trucks and crossovers, requiring that the brakes can stop the vehicle within a specific distance.
Honda announced two years ago that it was committed to applying “Brake Priority Logic” on 100 percent of all Honda and Acura passenger vehicles with automatic transmissions, with the first application coming to market in August of 2010. The vehicle was the all-new hybrid-only subcompact car, the 2011 Honda CR-Z. For the remainder of the 2011 model year, about half of Honda and Acura vehicles had the system. For 2012, the system, which Honda now calls Brake/Throttle Override, is on all Honda and Acura vehicles.
How the system works is explained to buyers in Honda and Acura vehicle owner’s manuals, but here’s a brief summary. The Brake/Throttle Override function applied to Honda and Acura models monitors the electronic throttle control (accelerator pedal) output signal. If that signal becomes static (meaning stuck) AND then the brake pedal is applied, after 0.1 seconds the throttle will be gradually reduced to near idle level over the course of about one-half second.
Ed Miller, Honda spokesman, tells The Car Connection that Honda chose to have a less abrupt throttle system than some other systems in the market. “The one-half second is quite noticeable to the driver, but we judge it to be less unsettling, so the driver can recognize the vehicle is slowing down due to reduction of engine power, but does not confuse the condition with a stalled engine,” said Miller.
Brake/Throttle Override is not applied to vehicles with manual transmissions because Honda believes that clutch is sufficient to allow the driver to decouple the engine power from the driven wheels.
In addition to Hyundai, corporate sibling Kia also now has brake throttle override technology standard across all model lines. Kia calls its system “smart pedal” technology and the automaker began implementing it 2010 on the 2010 Forte, Optima, Rondo and Sedona and the 2011 Sorento.
See how our editors rate the 2012 Kia Optima in this review.
The smart pedal system monitors and corrects for simultaneous application of both the brake and the accelerator. In such a case, the brakes override accelerator input and revert the engine/RPM to “idle” status. There is no difference in how the system works between manual and automatic transmission-equipped vehicles.
When Mazda launched the 2011 Mazda2 subcompact car in the U.S., its press material indicated that this was the first Mazda in the U.S. market to have brake-throttle override technology. All 2012 Mazda vehicles now have brake-throttle override as standard equipment. Mazda doesn’t have any different name for it.
Mazda’s brake-throttle override system works based on a signal from the brake pedal switch. If it detects a conflict where the car’s computer is receiving signals from both the accelerator and the brakes, the brakes take precedence. Brake-throttle override works on all vehicles, regardless of transmission or starting systems.
Mercedes-Benz started introducing “smart pedal technology” or “brake override system” in its vehicles as early as 2002 in the S600 and CL600. It is now in 100 percent of all Mercedes-Benz and Smart vehicles.
According to Mercedes-Benz, when the brake pedal is pressed and the accelerator pedal remains engaged, the electronic signal propelling the car is interrupted, and the vehicle is automatically slowed to idle.
There is no difference in general function of the smart pedal technology between manual and automatic transmission. Also, how the engine is started or stopped (e.g. key fob or push-button) does not influence the smart pedal technology function.
Check out our comprehensive review of the 2012 Mercedes-Benz C Class.
The phase-in of Brake Override in Mitsubishi vehicles began in 2010 with the 2011 Outlander Sport and was added as a running change in December 2010 to the rest of the lineup (except Endeavor). As of the 2012 model year, all Mitsubishi vehicles are equipped with the brake override system as standard equipment, regardless of whether manual, automatic or push-button start.
The Mitsubishi brake override system works by monitoring both the throttle pedal sensor and brake sensor. In the event that both the brake pedal and the throttle pedal are applied at the same time, the system will automatically override the throttle pedal, giving the brake pedal priority.
The entire lineup of Nissan and Infiniti vehicles has brake-throttle override systems, something the company first applied to its products in 2002 on the 2002 Infiniti Q45 and implemented across its vehicle portfolio in 2004. It has been a standard feature on every vehicle since that time.
How it works in Nissan and Infiniti vehicles: The system will not allow for the application of the brake and accelerator pedals at the same time. If they are pressed simultaneously, the electronic throttle will be cut instantaneously, once the brakes are applied. There is also an override for the push-button ignition system.
Nissan doesn’t brand the system, as it considers brake-throttle override to be an important safety feature that’s part of a safety suite of technologies working in the background to protect occupants, just like airbags and anti-lock brakes. But it did market the feature briefly in an ad, “Brake on a dime,” last summer that also appeared at the end of an educational video on the safety technology. Click here to see the video.
And, for a look at the redesigned 2013 Nissan Altima, see our review here.
Subaru incorporates brake throttle override in its new EyeSight system debuting on the 2013 Legacy and Outback models arriving in dealers this summer. The comprehensive safety system will be available on subsequent models. See more about the 2013 Subaru Outback in this review.
While EyeSight pricing hasn’t been announced yet, Subaru says the system will be one of the most affordable in the U.S. market.
Toyota began incorporating brake override in early 2010, and it was standard in all Toyota, Lexus and Scion vehicles by the end of 2010. In addition, it was retrofitted into all vehicles that were subject to the floor mat interference recalls. (For a recap of the Toyota sticking gas pedal and floor mat recalls, click here.) Toyota was the first full-line automaker to have this safety system standard across all car and truck models.
Toyota calls its system “smart stop technology.” There is no difference in how it works if the vehicle is equipped with push button start. The short version of how it works is this: If the accelerator is depressed beyond a certain low-power point and the brake is then depressed, the engine will return to idle speed as long as the brake is depressed.
Mike Michels, Toyota vice president of communications, tells The Car Connection that smart stop technology “is pretty much unnecessary” on manual transmission cars because the nature of the manual transmission makes the clutch readily available to disengage the engine.
Hybrid vehicles use motor/generators. “They are a motor when the car accelerates, and a generator, slowing the car down, when the car decelerates,” Michels said. “The motor/generator cannot do both at the same time, so in the case of the accelerator pedal being stuck and the driver hitting the brakes, it shuts off the electric motors and gas engine, and defaults to a generator to prevent damage and overload. Essentially, it acts like brake override, making any additional brake override logic unnecessary.”
Michels added that there are certain situations where drivers would want to intentionally use both pedals simultaneously, such as starting from a stop on a steep hill, or rocking the vehicle to get it unstuck from snow. For that reason, if the brake is depressed first (e.g., in order to hold the car on a hill), the engine will respond and the vehicle can be driven from a standstill, assuming the brake is then released.
For a comprehensive look at the 2012 Toyota Camry, check out our review of the mid-size sedan.
All Volkswagen and Audi vehicles have had brake-throttle override system since 2002. It applies to manual and automatic transmissions.
Called “smart pedal technology,” the Volkswagen system monitors the application of the vehicle’s throttle (gas pedal) and brakes. If the driver applies the brake pedal while driving with an actuated accelerator pedal, the engine control system returns the engine to idle, disregards gas pedal input, or, in situations where a vehicle’s brakes have not been properly maintained, reduces engine torque, allowing the vehicle to be stopped with its brakes.
Learn more about the 2012 Volkswagen Passat, the German automaker’s first American-made vehicle since 1985, in this review.
This story originally appeared at The Car Connection