Electronic Stability System
WHEREAS, worldwide, single vehicle crashes represent nearly a third of all crashes with a fatal occupant injury,
WHEREAS, Electronic Stability Control (ESC) effectiveness studies completed in different countries and different parts of the world have found that ESC systems reduce the risk of occupant fatality in single vehicle crashes between 25 and 35 percent,
Adopted: October 2010 and updated October 2017
BE IT RESOLVED, the installation of Electronic Stability Control Systems into every new motor vehicle with ongoing research into methods to cost effectively optimize ongoing system refinements should be supported.
ELECTRONIC STABILITY CONTROL SYSTEM: RATIONALE & BACKGROUND INFORMATION
There have been significant improvements in passive safety design for automobiles, as well as successes in increasing safe behaviors among drivers and passengers, however, in the United States there were 35,092 traffic fatalities in 2015. This represented an increase from the previous year [1]. Secondary prevention is the reduction of injuries and deaths after a crash, using technologies such as seat belt pre-tensioners and airbags. Primary prevention is the reduction of crashes themselves.
Electronic Stability Control (ESC) technology can reduce crash rates and, thus, prevent injuries and fatalities. ESC systems combine an Antilock Braking System (ABS) with a Traction Control System (TCS) to multiply the advantages of both systems. ABS prevents wheel-lock when the brakes are applied and TCS controls traction to prevent wheel-spin when accelerating. [2, 3, 10].
With ESC, the two technologies work in synergy, using the speed sensors on each wheel along with the ability to brake individual wheels, which are the basis of antilock braking and traction control systems. ESC adds a steering angle sensor, as well as a vehicle rotation sensor that measures rotation around the vehicle’s vertical axis. ESC also provides a control unit that monitors when the steering and rotation sensors detect that a vehicle is about to travel in a direction different from the one indicated by the steering wheel position. Then, ESC automatically brakes the appropriate wheel to help the driver maintain control. Engine throttle may also be reduced. Most vehicle manufactures use different technology and maintain unique names for their systems.
The United States began a mandate to phase in ESC for passenger vehicles in 2008 with FMVSS 126. FMVSS 136 was issued in June 2017 mandating ESC for new heavy truck tractors and buses with a gross vehicle weight greater than 26,000 pounds. Only 7.3 percent of the light vehicle fleet of model year 2003 was equipped with ESC, but had risen to 29% by the 2006 model year. Other countries have been installing ESC into vehicles for several years before the United States.
The European Accident Causation Survey (EACS), contained data from 1,674 crashes in five European countries (1995 to 1999). It found improved outcomes for vehicles equipped with ESC, such as injury accidents reduced by 18%, fatal accidents reduced by 34%, injury accidents in loss of control situations reduced by 42% and fatal accidents in loss of control situations reduced by 67%. [4, 10].
The Swedish National Road Administration and Swedish universities looked at 2000 to 2004 traffic data and detected a 22 percent reduction in collision and injury for vehicles equipped with ESC. [5].
Newly registered Mercedes vehicles equipped with ESC, listed in the German “Statistische Bundesamt,” realized a reduced number of side-impacts, rollovers, and average injury severity as compared to vehicles without ESC. This included all collisions reduced by 15% and single vehicle crashes reduced by 30%. [7, 10]. Volkswagen and Audi reported ESC prevented 80% of all skidding accidents and 35% of all fatal accidents. [6].
The Institute for Traffic Accident Research and Data Analysis collected traffic accident data from 3 popular Toyota models equipped with ESC in Japan found a 35% reduction in casualties (for single vehicle and head-on collisions), a 30% reduction in head-on collisions and ESC is most effective in the 40 kph to 100 kph range. [7].
In the United States, NHTSA looked at 1997 to 2003 Fatal Automotive Reporting System data as well as data from five states from 1997 to 2002 and reported a reduction for ESC-equipped vehicles in severity of single vehicle crashes. Passenger cars realized 35% reduction, SUV’s realized a 67% reduction
The Insurance Institute for Highway Safety looking at US data, noted the following reductions in fatal crash risk for ESC-equipped vehicles:
- Single vehicle crashes were reduced by 56%
- Multi-vehicle crashes were reduced by 17%
- All fatal crashes were reduced by 35%
Most research and implementation policy predicted the lives and dollar values saved from implementing ESC across vehicle fleets. While the analysis continues, the overall savings have largely been supported. It is unlikely that a push will ever come to retrofit ESC technology, thus full implementation will be through attrition of vehicle fleets.
References:
[1] NHTSA DOT HS 812 412, 2015 Data, “Traffic Safety Facts, May 2017, National Highway Traffic Safety Administration, Washington D.C.
[2] Liebemann, E K, Meder, K, Schuh, J, Nenninger, G. “Safety and Performance Enhancement: The Bosch Electronic Stability Control (ESP).” ESV paper no. 05-0471. Washington D.C. 2005.
[3] Svenson, A L, HAC, A. “Influence of Chassis Control Systems on Vehicle Handling and Rollover Stability.” ESV paper no. 05-0324. Washington DC 2005.
[4] Sferco R, Page Y, LeCoz, J-Y, Fay, P. “Potential Effectiveness of Electronic Stability Programs (ESP) – what European Field Studies tell us.” ESV paper no. 2001-S2-0-327. Amsterdam 2001.
[5] Lie, A, Tingvall, C, Krafft, M, Kullgren, A. “ The Effectiveness of ESC (Electronic Stabitity Control) in Reducing Real Life Crashes and Injuries.” ESV paper no. 05-0135. Washington D.C. 2005.
[6] Zobel, R, Becker, H,Stanzel, M, Rieger, G, Scheef, J. “Active Safety Systems Change Accident Environment of Vehicles Significantly – A Challenge for Vehicle Design.” ESV paper no. 05-0074. Washington D.C. 2005.
[7] Garrott, W R. “ Status of NHTSA’s ESC Research”, presentation 4-19-05, Pages 1 – 12. NHTSA.
[8] Dang, J. Evaluation Note – “Preliminary Results Analyzing the Effectiveness of Electronic Stability Control (ESC) Systems.” (DOT HS 809 790).
[9] Farmer, C M. “Effects of Electronic Stability Control on Automobile Crash Risk.” Traffic Injury Prevention, 5:317-325, 2004.
[10] Bahouth, G. “Real World Crash Evaluation of Vehicle Stability Control (VCS) Technology.” 49th Annual Proceedings Association for the Advancement of Automotive Medicine, pages 19 – 34. Boston 2005.