Research has shown that many of the non-wearers of seat belts would use their seat belt with some encouragement. Seat belt reminders are intended to bring these "part time users" to wearing their belt, whilst at the same time not be so annoying that the small proportion of non-wearers would try to disable the system.
An audible seat belt reminder is a device that gives a sound warning whenever a seat is occupied, but the seat belt is not fastened. ETSC experts estimate that audible seat belt reminders for front seats can raise seat belt wearing among front seat occupants to 97%. The benefits of requiring audible seat belt reminders for the front seats of cars in the European Union exceed the costs by a ratio of 6 to 1. (ETSC, 2003)
The European New Car Assessment Program (EuroNCAP) has therefore started providing added point bonuses for vehicles fitted with seat belt reminders (see the assessment protocol). In the June 2004 rating, all but two of the cars had some form of intelligent seat belt reminder, and an intelligent seat belt reminder for the rear seats was introduced on a car (Volvo's S40) for the first time.
While new cars are increasingly equipped with seat belt reminders, efforts are also being made to promote retrofitting of old cars. A study performed by the Swedish Road and Transport Research Institute (VTI) has concluded that a seat belt reminder for retrofit at driver position would reduce road fatalities in Sweden by about 7% yearly if it were fitted into 2 million Swedish cars.
Following a competition organised by the Swedish Insurance Federation and the Swedish Motor Vehicle Inspection Company, an inexpensive retrofit seat belt reminder system for the driver seat is currently being developed at Autoliv Gothenburg.