Electronic stability control
Developed to help the driver maintain the intended line through a corner; an onboard computer monitored several vehicle operating parameters through various sensors.
The TCL system's standard wheel slip control function enabled better traction on slippery surfaces or during cornering.
In addition to the system's individual effect, it also worked together with the Diamante's electronically controlled suspension and four-wheel steering to improve total handling and performance.
From 1987 to 1992, Mercedes-Benz and Bosch co-developed a system called Elektronisches Stabilitätsprogramm ("Electronic Stability Program", trademarked as ESP) to control lateral slippage.
[17] StabiliTrak was made standard equipment on all GM SUVs and vans sold in the U.S. and Canada by 2007, except for certain commercial and fleet vehicles.
It involves an omnibus computer integration of engine, traction control, Stabilitrak electronic stability control, steering, and adaptive continuously variable road sensing suspension (CVRSS), with the intent of improving responsiveness to driver input, performance, and overall safety, similar to Toyota/Lexus Vehicle Dynamics Integrated Management.
During a moose test, Swedish journalist Robert Collin of Teknikens Värld rolled a Mercedes A-Class (without ESC) at 78 km/h in October 1997.
The Swedish road safety administration issued a strong ESC recommendation and in September 2004, 16 months later, the purchase rate was 58%.
The NHTSA required all new passenger vehicles sold in the US to be equipped with ESC as of the 2012 model year, and estimated it will prevent 5,300–9,600 annual fatalities.
[29] This may happen, for example, when skidding during emergency evasive swerves, understeer or oversteer during poorly judged turns on slippery roads, or hydroplaning.
During high-performance driving, ESC can intervene when unwanted, because steering input may not always be indicative of the intended direction of travel (such as during controlled drifting).
Most activate a dashboard indicator light[33] and/or alert tone; some intentionally allow the vehicle's corrected course to deviate very slightly from the driver-commanded direction, even if it is possible to more precisely match it.
[34] All ESC manufacturers emphasize that the system is not a performance enhancement nor a replacement for safe driving practices, but rather a safety technology to assist the driver in recovering from dangerous situations.
In simple systems, a single button may disable all features, while more complicated setups may have a multi-position switch or may never be fully disengaged.
ESC systems—due to their ability to enhance vehicle stability and braking—often work to improve traction in off-road situations, in addition to their on-road duties.
In slippery conditions, this means when one wheel loses traction, power will counter-productively be fed to that axle instead of the one with higher grip.
In these systems, or in vehicles without ABS, the performance in emergency braking in slippery conditions is greatly improved as grip state can change extremely rapidly and unpredictably off-road when coupled with inertia.
Numerous studies around the world have confirmed that ESC is highly effective in helping the driver maintain control of the car, thereby saving lives and reducing the probability of occurrence and severity of crashes.
The United States Insurance Institute for Highway Safety (IIHS) issued its own study in June 2006 showing that up to 10,000 fatal US crashes could be avoided annually if all vehicles were equipped with ESC.
ESC is described as the most important advance in auto safety by many experts,[37] including Nicole Nason, administrator of the NHTSA,[38][39] Jim Guest and David Champion of Consumers Union of the Fédération Internationale de l'Automobile (FIA),[40][41] E-Safety Aware,[42] Csaba Csere, former editor of Car and Driver,[43] and Jim Gill, long time ESC proponent of Continental Automotive Systems.
The IIHS requires that a vehicle must have ESC as an available option in order for it to qualify for their Top Safety Pick award for occupant protection and accident avoidance.
Some systems also offer an additional mode with raised thresholds, so that a driver can utilize the limits of their vehicle's grip with less electronic intervention.
Some ESC systems that lack an off switch, such as on many recent Toyota and Lexus vehicles, can be temporarily disabled through an undocumented series of brake pedal and handbrake operations.
The Canadian province of Quebec was the first jurisdiction to implement an ESC law, making it compulsory for carriers of dangerous goods (without data recorders) in 2005.
[50] The United States followed, with the National Highway Traffic Safety Administration implementing FMVSS 126, which requires ESC for all passenger vehicles under 10,000 pounds (4536 kg).
8 ELECTRONIC STABILITY CONTROL SYSTEMS was sponsored by the United States of America,[67] and is based on Federal Motor Vehicle Safety Standard FMVSS 126.
In the US, federal regulations have required that ESC be installed as a standard feature on all passenger cars and light trucks as of the 2012 model year.
However, consumer awareness affects buying patterns, so that roughly 45% of vehicles sold in North America and the UK were purchased with ESC,[72] contrasting with 78–96% in other European countries such as Germany, Denmark, and Sweden.
[citation needed] The 2009 Toyota Corolla in the United States (but not Canada) had stability control as a $250 option on all trims below that of the XRS, which had it as standard.
[69] In Canada, for the 2010 Mazda3, ESC was an option on the midrange GS trim as part of its sunroof package, and is standard on the top-of-the-line GT version.
