Emergency Signal System is an active safety system, designed and developed by Mazda Corporation, which is used to convey the message of emergency brake stop to the vehicle running just behind.
Many times, it is observed that vehicle collides with the rear end of the next vehicle simply because the driver of the colliding vehicle fails to recognize that the next vehicle is braking hard. Such accidents contribute a significant number of the total road accidents all over the world. Thus, it is immensely necessary to convey the signal of hard braking to the vehicle running behind. So, it will eventually minimize such accidents. This is where Emergency Signal System comes into action.
The root cause of the problem of rear-end collision lies in the fact that a hazard light or brake light glows in the similar fashion for panic or hard braking as it does for the normal braking. It is impossible to detect whether the car ahead is braking at a normal pace or it is hard braking. This difficulty is the working principle of Emergency Signal System.
On braking a vehicle with ESS, the hazard lamp glows at a very high frequency or in a flashing manner. Thus, they try to alert the driver of the vehicle running behind. So, the driver of the following vehicle easily recognizes that the next vehicle is undergoing a hard braking. S/he also adjusts the braking force so as to avoid a collision.
Emergency Signal System does not guarantee the elimination of rear-end collisions. But, manufacturers certainly find it to be very useful in reducing such accidents. However, the efficiency of this system depends on the ambient conditions such as light availability and it also depends on how attentive the driver of next vehicle is.