In engineering

Engineering

Engineering is the discipline, art, skill and profession of acquiring and applying scientific, mathematical, economic, social, and practical knowledge, in order to design and build structures, machines, devices, systems, materials and processes that safely realize improvements to the lives of...

, active safety systems are systems activated in response to a safety problem or abnormal event. Such systems may be activated by a human operator, automatically by a computer

Computer

A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...

 driven system, or even mechanically. In nuclear engineering

Nuclear engineering

Nuclear engineering is the branch of engineering concerned with the application of the breakdown as well as the fusion of atomic nuclei and/or the application of other sub-atomic physics, based on the principles of nuclear physics...

, active safety contrasts to passive safety in that it relies on operator or computer automated intervention, whereas passive safety systems rely on the laws of nature to make the reactor respond to dangerous events in a favourable manner.

Examples

• The computer operated control rods in a nuclear power station provide an active safety system, whereas a fuel that produces less heat at abnormally high temperatures constitutes a passive safety feature.
• Collision avoidance systems in a modern car.
• Many buildings have interconnected fire alarms that can be triggered manually by pushing a button or breaking a glass plate attached to sensors.

Automotive Sector

In the automotive sector the term Active Safety (or Primary Safety) refers to safety systems that are active prior an accident. This has traditionally referred to non-complex systems such as good visibility from the vehicle. Now days however, this area contains highly advanced systems such as anti-lock braking system

Anti-lock braking system

An anti-lock braking system is a safety system that allows the wheels on a motor vehicle to continue interacting tractively with the road surface as directed by driver steering inputs while braking, preventing the wheels from locking up and therefore avoiding skidding.An ABS generally offers...

, electronic stability control

Electronic stability control

Electronic stability control is a computerized technology that may potentially improve the safety of a vehicle's stability by detecting and minimizing skids. When ESC detects loss of steering control, it automatically applies the brakes to help "steer" the vehicle where the driver intends to go...

 and collision warning/avoidance through automatic braking. This compares with Passive Safety (or Secondary Safety), which are active during an accident. To this category belongs e.g. seat belts, deformation zones and air-bags.

Since the progress within passive safety systems have reach very far, the automotive industry has shift its attention to active safety where still a lot of new unexplored areas exists. Research today focuses primary on collision avoidance with other vehicles, pedestrians and wild animals and vehicle platooning.

Active Safety Systems, some examples

• good visibility from driver's seat,
• low noise level in interior,
• legibility of instrumentation and warning symbols,
• early warning of severe braking ahead,
• head up displays,
• good chassis balance and handling,
• good grip,
• anti-lock braking system
  Anti-lock braking system
  An anti-lock braking system is a safety system that allows the wheels on a motor vehicle to continue interacting tractively with the road surface as directed by driver steering inputs while braking, preventing the wheels from locking up and therefore avoiding skidding.An ABS generally offers...
  
  ,
• Electronic Stability Control
  Electronic Stability Control
  Electronic stability control is a computerized technology that may potentially improve the safety of a vehicle's stability by detecting and minimizing skids. When ESC detects loss of steering control, it automatically applies the brakes to help "steer" the vehicle where the driver intends to go...
  
  ,
• Chassis assist,
• intelligent speed adaptation
  Intelligent speed adaptation
  Intelligent Speed Adaptation , also known as Intelligent Speed Assistance, is any system that constantly monitors vehicle speed and the local speed limit on a road and implements an action when the vehicle is detected to be exceeding the speed limit...
  
  ,
• brake assist
  Brake assist
  Brake Assist is a generic term for an automobile braking technology that increases braking pressure in an emergency situation. The first application was developed jointly by Daimler-Benz and TRW/LucasVarity...
  
  ,
• traction control
  Traction control system
  A traction control system , also known as anti-slip regulation , is typically a secondary function of the anti-lock braking system on production motor vehicles, designed to prevent loss of traction of driven road wheels...
  
  ,
• collision warning/avoidance,
• adaptive or autonomous cruise control system
  Autonomous cruise control system
  Autonomous cruise control is an optional cruise control system for road vehicles. It makes no use of satellite or roadside infrastructures nor of any cooperative support from other vehicles. Hence control is imposed based on sensor information from on-board sensors only...
  
  .

Passive Safety Systems, some examples

• passenger safety cell,
• deformation zones,
• seat belts,
• loadspace barrier-nets,
• air-bags,
• laminated glass,
• correctly positioned fuel tanks,
• fuel pump kill switches

See also

• Passively safe
• Intelligent Speed Adaptation (ISA)
• Electronic Stability Control
  Electronic Stability Control
  Electronic stability control is a computerized technology that may potentially improve the safety of a vehicle's stability by detecting and minimizing skids. When ESC detects loss of steering control, it automatically applies the brakes to help "steer" the vehicle where the driver intends to go...