How Electronic Stability Programme (ESP) works

You either have it or you don’t. ESP is probably one of the most important safety features to arrive on the scene since the introduction of seatbelts. Until you’ve actually driven a vehicle with and without ESP on a test track and compared the differences, it’s difficult to understand exactly how important this device is. Each manufacturer has their own name for an equivalent system an explaination of some of these is here

For those who don’t know what ESP is, let’s go right back to basics…

The electronic stability programme is a further enhancement to the anti-lock braking system (ABS) and traction control system (TCS). The ESP is designed to detect a difference between the driver’s control inputs and the actual response of the vehicle. When differences are detected, the system intervenes by providing braking forces to the appropriate wheels to correct the path of the vehicle. This automatic reaction is engineered for improved vehicle stability, particularly during severe cornering and on low-friction road surfaces, by helping to reduce over-steering and under-steering.

To implement ESP functionality, additional sensors must be added to the ABS system. A steering wheel angle sensor is used to detect driver input with a yaw rate sensor and a low-G sensor that measure the vehicle response.

Electronic stability programs are also known as anti-skid control and work automatically to correct sideways movement in a vehicle. Adaptive ESP, the latest step forward, automatically adjusts itself depending on where loads are placed. The good thing about such systems is that drivers don’t need any lessons in how to use them. Most of the ESP systems on today’s vehicles are made by Bosch.

ESP won’t save you if you lose it big time, but for most everyday examples of bad driving – especially in the wet – ESP will simply wink its little orange light on the dashboard and correct the vehicle often without the driver feeling a thing. The only danger, of course, is that once drivers know they have an ESP system on board, they may just be tempted to push their luck that little bit further on the roads.
How ESP works
ESP controls vehicle dynamics by selectively braking individual wheels and reducing engine torque. Within the limits set by physical laws, this markedly increases driving safety. As a side effect, because ESP distributes the braking force across the axles in accordance with the current load, the wear on both brakes and tires is reduced, leading to lower maintenance costs and safety through increased vehicle stability.

After evaluating almost 1 million accidents involving personal injury, Toyota came to the conclusion that the standard use of ESP could reduce the number of driving accidents by up to 50%. In the recent presentation to UK Fleet Managers Matthew Avery, crash research manager at Thatcham- one of the world’s leading automotive research technology centres – said, “Research from Japan, USA and Sweden has shown that accident rates reduce by over 30% on cars fitted with ESP” His advise? “ Choose vehicles with five stars in the euro NCAP crash tests, seats with a ‘good’ rating in the Thatcham whiplash test and ESP fitted as standard” . It therefore stands to reason that in Australia, the Victorian Vehicle Safety Strategy includes the key objective of increasing the proportion of vehicles on the road equipped with high quality active crash avoidance features, such as ABS and ESP.

In an ideal world, every driver would receive skid awareness training as early as possible in their driving career. Sadly, most people’s first skid is a real-world experience – an unforeseen and potentially disastrous event for which they have had no adequate rehearsal. Drivers should have the opportunity to understand the causes of skids and the advanced driving technology and techniques that can help to reduce the risk of becoming involved in a crash.

Institute of Advanced Motorists

Author: Geraldine Herbert

Motoring Editor and Columnist for the Sunday Independent and editor of wheelsforwomen. Geraldine is also a regular contributor to Good Housekeeping (UK) and to RTÉ Radio One, Newstalk, TodayFM and BBC Radio. You can follow Geraldine on Twitter at @GerHerbert1

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