What is a crash test dummie?

Its like an adult size dool fitted with censors, they put them in the vehicle and then take the vehicle and wreck it into walls, conners of the building, poles and then they see how well vehicle does to protect the dummie which is fitted with sensors green is sensor ok, yellow minor bruses, red is bad injury or death so when it hits the balls that are fitted with color are different thickness for force of impact, so which ever breaks that's the injury.