High-Tech Vehicle Safety Systems

Brake Assist

In emergency stop situations, some drivers fail to brake hard enough, or soon enough, and are consequently involved in more serious collisions than might otherwise be the case. Brake assist systems apply the brakes fully in order to prevent a crash or at least to reduce the collision severity.

Brake Assist

How do they work?

Modern vehicles are equipped with power-assisted braking systems. These feature a brake booster system that typically uses either engine vacuum or an electric motor to reduce the force that the driver needs to apply on the brake pedal to generate the desired level of vehicle braking.

In vehicles also equipped with brake assist, a sensing system identifies when the driver is pushing on the brake pedal hard and rapidly, with the intention of making an emergency stop. A control system then activates the brake booster system to maximize the braking effort early in the event.

Brake assist provides for a greater degree of braking than in the case of tentative driver action. The system can result in a collision being completely avoided or, at least, it will minimize the severity of a collision that does occur by reducing the vehicle's speed as much as possible.

Some systems use an adaptive learning technique where the sensing and control system monitors the driver's braking pattern and identifies the characteristics of non-emergency and emergency braking actions.

What can science tell us?

Real World Safety Benefits of Brake Assistance Systems; Joerg J Breuer, Andreas Faulhaber, Peter Frank and Stefan Gleissner; Paper No. 07-0103; Proc. 20th International Technical Conference on the Enhanced Safety of Vehicles Conference (ESV); Lyon, France; June, 2007
The first brake assist system (BAS) was developed by Mercedes-Benz and introduced in 1996. It has been a standard feature on all Mercedes-Benz passenger cars since 1997. Recent statistical analyses of German accident data show significant safety benefits of this technology: Both the percentage of severe accidents involving pedestrians as well as the rate of rear end collisions are lower for vehicles equipped with BAS than vehicles without BAS. The conventional brake assist (BAS) is now completed by radar based adaptive brake assistance functions (BAS PLUS and PRE-SAFE Brake) which have demonstrated their benefits both in internal and external tests.

Are Expected and Observed Effectiveness of Emergency Brake Assist in Preventing Road Injury Accidents Consistent?; Yves Page, Jean-Yves Foret-Bruno and Sophie Cuny; Proc. 19th ESV Conf.; Paper No. 05-0268; June, 2005 (235 KB PDF)
This paper estimates the expected and the observed effectiveness of Emergency Brake Assist (EBA) systems in terms of reduction in injury accidents in France. The effectiveness estimates were for a 7.5% reduction of car occupants fatalities, a 10% drop in pedestrian fatalities, and an 11% reduction in overall injuries.

Useful links

Quick Facts

  • The vast majority of drivers react to emergency situations by braking
  • Most drivers don't apply full braking early enough
  • Brake assist boosts the braking action in an emergency
  • This can prevent a crash or reduce collision severity

Associated systems:

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