Active systems are those systems which are activated in response to an abnormal event such as a safety problem. These systems can be activated manually by a human operator or automatically by a computer driven system or it can be achieved mechanically. Such technologies could help and avoid collisions and mitigation and are expected to play a major role in future. Companies like Bosch, Delphi and TRW are working on developing such safety traits.
Here are some examples of active safety - Good visibility from driver's seat, Head up displays, Adaptive or autonomous cruise control system, Anti-lock braking system, Electronic Stability Control, Brake Assist, Early warning of severe braking ahead, Traction control, Chassis assist, Good grip, Low noise level in interior, Legibility of instrumentation and warning symbols, Intelligent speed adaptation, Good chassis balance and handling and Collision warning/avoidance.On the other hand these features act as passive safety – Passenger safety cell, Airbags, Corrected positioned fuel tanks, Fuel pump kill switch, Seat belts, Laminated glass, deformation zones and Loadspace barrier – nets.