Your last statement is rather wide sweaping and I would suggest not particularly accurate.
To take the Renault rage as a sample (for no other reason than I know some of the safety results) the Clio is a small car and the current model is very safe (scoring the maximum of five stars on the European safety tests). In contrast I understand that the older model of the seven-seat Vauxhal Zaffia MPV (around 2001) was very poor on rear-end safety: the passengers in the rear two seats were liable to serious injury if the vehicle was hit from behind.
It is probably more accurate to say that the more modern the car the safer it is, than to say that small cars are less safe than large cars.
no subject
To take the Renault rage as a sample (for no other reason than I know some of the safety results) the Clio is a small car and the current model is very safe (scoring the maximum of five stars on the European safety tests). In contrast I understand that the older model of the seven-seat Vauxhal Zaffia MPV (around 2001) was very poor on rear-end safety: the passengers in the rear two seats were liable to serious injury if the vehicle was hit from behind.
It is probably more accurate to say that the more modern the car the safer it is, than to say that small cars are less safe than large cars.