Usually the 2 systems are split into left front and right rear comprising one system and right front and left rear comprising the other system. For safety, this is done so that usually only two wheels lose their braking ability at the same time and that both sides of the car have at least one braking system working and both ends of the car have at least one system working. With only 1 system working there is longer stopping distances and repairs should be done before driving again.[3][4][5][6]