Driver assistance systems

Assistance or automation: the difference

Assistance systems support you: they warn or intervene briefly. Control remains entirely in your hands.

Automation goes further: the vehicle takes over the driving in defined situations. But even then you remain responsible for as long as you must be able to take back control.

The most important systems

• ABS: prevents the wheels from locking – the vehicle stays steerable under braking. Limit: it does not shorten the braking distance on ice.
• ESP: brakes individual wheels to stabilise the vehicle. Limit: it cannot recover a plainly excessive entry speed.
• Automatic emergency braking: brakes by itself when a collision threatens. Limit: narrow objects such as cyclists are not always detected.
• Adaptive cruise control: maintains speed and gap. Limit: it reacts late to vehicles cutting across.
• Lane keeping assist: corrects the line. Limit: faded markings or roadworks confuse it.
• Blind spot warning: signals vehicles in the area you cannot see. Limit: it does not replace the shoulder check.

Three modes of action – which system does what

Assistance systems intervene to very different degrees. Once you know the three modes of action, you can classify any new system straight away – and you know how much it takes off your hands, and how much it does not.

• Informing and warning – the system reports, you act: Blind spot warning (watches the neighbouring lane and your blind spot), traffic sign recognition (reads speed limits and warns when you are too fast), drowsiness and attention monitor (detects fatigue and inattention), night vision assist (makes people, animals and objects visible in the dark by infrared).
• Continuously supporting – the system keeps regulating alongside you: intelligent speed assistance (ISA) (continuously adapts your speed to limits and the road ahead), adaptive cruise control (ACC) (holds your set speed and the gap to the vehicle in front).
• Temporarily intervening – the system briefly takes over in an emergency: automatic emergency braking (brakes by itself or boosts your braking force when a collision looms), emergency lane keeping assist (steers back when you get too close to the edge line).

Modes of action at a glance

A informing and warning, B continuously supporting, C (temporarily) intervening.

Remember: whichever category – the responsibility stays with you. None of the three groups releases you from watching, anticipating and intervening.

Classification and choice of systems follow the BFU – Swiss Council for Accident Prevention: bfu.ch · smartrider.ch.

The limits of every system

Sensors: cameras and radar are limited by snow, heavy rain, fog, backlight or dirt. A sensor covered in mud simply stops working.

Physics: no system can overcome the laws of grip. If the grip is not there, it is not there – with or without electronics.

Switching systems on and off

Many systems can be switched off; some switch themselves back on when the engine is started.

The sensible approach is to leave switched on those that work in the background – ABS, ESP, emergency braking – and to use deliberately those that intervene in the driving, such as cruise control or lane keeping.

Remember: however many systems are on board, you are driving and you are answerable. An assistant is a safety net, not a pilot.