Most of the newer cars have back-up-sensors that warn the driver before the rear bumper actually comes in contact with something.
Most people probably think that this valuable feature came out of the minds of engineers but it was recently disclosed that it was a concept developed by a Chinese farmer.
His invention was simple yet effective.
Scroll down to see a photo of the prototype back-up-sensor being demonstrated.
It emits a high pitched squeal when the vehicle backs into something.