Adding to that, it helps to think about how the types of accident are dramatically different.
1. In a regular car, most accidents are at relatively low speed, and in those at high speed are generally front collisions (for at least one of the cars), so cars are designed in a way that the front and back are crumple zones to absorb the shock and limit energy transfer to the passengers. So after protecting passengers from flying out of (or within) the car with the belt, airbags are there to prevent whiplash from front/rear hits.
2. In a racing car, impacts are usually at high speed, and in basically any direction. Accelerations and decelerations will be significantly more brutal, and particularly for rally cars, vehicle rollover is really common. Hence the rigid cage + harness to reduce direct damage to the driver in those events. But even so, since the helmet's weight and the rigidity of the vehicle can make whiplash and basilar skull fractures, there are also helmet restraints (like HANS[0]) to reduce this risk.
1. In a regular car, most accidents are at relatively low speed, and in those at high speed are generally front collisions (for at least one of the cars), so cars are designed in a way that the front and back are crumple zones to absorb the shock and limit energy transfer to the passengers. So after protecting passengers from flying out of (or within) the car with the belt, airbags are there to prevent whiplash from front/rear hits.
2. In a racing car, impacts are usually at high speed, and in basically any direction. Accelerations and decelerations will be significantly more brutal, and particularly for rally cars, vehicle rollover is really common. Hence the rigid cage + harness to reduce direct damage to the driver in those events. But even so, since the helmet's weight and the rigidity of the vehicle can make whiplash and basilar skull fractures, there are also helmet restraints (like HANS[0]) to reduce this risk.
https://en.wikipedia.org/wiki/HANS_device