Using the safety belt in the rear seats of the car reduces death risk by almost a half

From Eurekalert (edited for clarity):

The Spanish Government's General Traffic Directorate (DGT) has been insisting for many years on that use of seat belts on the road can save lives. However, most drivers associate this warning with the use of this device in the front seats , whereas its use in the rear seats is much less.

In light of this, the paper ‘Individual factors affecting the risk of death for rear-seated passengers in road crashes’, prepared by researchers Pablo Lardelli Claret, José Juan Jiménez Moleón and Aurora Bueno Cavanillas (of the Department of Preventive Medicine and Public Health of the University of Granada) and Juan de Dios Luna del Castillo (of the Department of Statistics), shows the importance of the use of rear seat belts. Their work has produced very significant data such as: the use of rear seat belts reduces the risk of death by 44 per cent.

The research work, carried out from data provided by the Government's General Traffic Directorate on road crashes occurring in Spain between 1993 and 2002, analyses the death of rear seat occupants according to their age, gender, use of restraint systems and seating position. To carry out this analysis they only considered data concerning vehicles occupied by two or three rear-seated passengers for accidents in which at least one of these passengers was killed. The authors analyzed all 5,260 rear-seated passengers, who were travelling in 2,266 vehicles 2,851 of which were killed.

Women and children
An increased risk of death was observed in this analysis carried out at the UGR for females and children aged under 3; women are 28% more likely to die than men, and children aged under 3, 70% more likely than those aged between 15 and 19.

The research work also concludes that the risk of death in the rear-seats of a vehicle is higher as we get older. According to the analysed DGT data, people older than 64 years old are the highest risk sector when traveling in the rear seats, as they have 407% more chance of dying than persons aged between 15 and 19 years old.
The last variable analysed by the researchers from Granada is the death of passengers with regard to their location in the rear of the car. Their work shows that those passengers traveling in the centre or right seat [cars in Spain are left-hand drive and drive on the right] are less likely to be killed in the event of an accident than those in the left seat.