Seat Belts

Seat Belts

Summary:

  • Seat belts are designed to retain people in their seats during a crash, and so prevent or reduce injuries.

  • Safety belts form a fundamental part of the occupant protection system in all modern motor vehicles.

The Effectiveness of Seat Belts

  • The earliest major study of seat belts, in Sweden in the 1960s, found that they reduced the risk of injuries for drivers by 57% at lower speeds and 48% at higher speeds, compared to unbelted drivers. Seatbelts also reduced the risk of injuries for all occupants by 63% at lower speeds to 55% at higher speeds.

  • USA studies in the 1960s and 1970s produced various estimates of the effectiveness of seat belts, including:

    • Car occupants using a lap belt had a 73% lower fatality rate, a 53% lower serious injury rate, and a 38% lower injury rate than unrestrained occupants.

    • Users of three point belts had a 60% lower serious injury rate and 41% lower rate of all injuries compared with unrestrained occupants.

    • Users of three point belts had a 56.5% lower injury rate than unbelted occupants.

  • In the 1980s, three point seat belts were estimated to be 40% to 50% effective at preventing fatal injuries, 45% to 55% effective at preventing serious injuries and 10% effective at preventing slight injuries.

  • In 2000, the USA estimated that seat belts reduced the number of fatalities in passenger cars by 45% and in light trucks by 60%.

  • Another USA study suggested that around 60% of fatally injured unbelted occupants would have survived if they had been wearing their seat belt.

  • A meta-analysis of 29 studies of seat belt use in 2009 found that:

    • For drivers of cars and vans, seat belts were found to be 50% effective at preventing fatal injuries, 45% effective at preventing serious injuries and 25% effective at preventing minor injuries.

    • For front seat passengers, seat belts were found to be 45% effective at preventing fatal injuries, 45% effective at preventing serious injuries, and 20% effective at preventing minor injuries.

    • For rear seat passengers rear seat belts were found to be less effective, being 25% effective at preventing fatal injuries, 25% effective at preventing serious injuries, and 20% effective at preventing minor injuries.

Seat Belts in Great Britain

  • The first major UK studies were published in the late 1970s, and found that seat belts when worn reduced severe or life threatening injuries by 44% and ‘moderate’ injuries by 44%.

  • The law requiring drivers and adult front seat passengers in cars and light vans to wear a seat belt was introduced in Great Britain on the 31st January 1983. In 1989, it became compulsory for rear seat passengers under 14 years old to use seat belts, if fitted, or an appropriate child restraint if available. In 1991, it became compulsory for adult passengers to wear seat belts in the rear if seat belts are fitted.

  • Before the introduction of the law in 1983, around 40% of drivers and front seat passengers wore seat belts. This increased to around 95% immediately following the law’s introduction and remained at that level over the course of the year.

  • There was a 25% reduction in driver fatalities and a 21% reduction in the number of serious driver injuries in the year following the law’s introduction. Slightly larger falls were seen for front seat passengers, for whom there was a 29% reduction in fatal injuries and a 30% reduction in serious injuries.

  • It was estimated that the seat belt law saved the lives of 241 drivers and 147 front passengers in 1983 and 270 drivers and 181 front passengers in 1984.

  • Other studies found a 20% reduction in the number of drivers, and a 33% reduction in front seat passengers, admitted as in-patients. There was also a 20% reduction of seriously injured drivers and a 16% fall in seriously injured front seat passengers.

  • Seat belt use in passenger vehicles in Great Britain is very high. Almost all (95%) of car drivers and front seat passengers wear seat belts. In the rear of cars, 89% of passengers wear seat belts or use child car restraints.
  • However, seat belt use is lower in other vehicles where only 69% of drivers and front seat passengers wear seat belts.

  • Sixty per cent of road casualties in Great  Britain are car occupants. Despite the effectiveness of seat belts, 109,046 people were killed or injured while travelling in cars, in 2016. It is not recorded how many were or were not wearing seat belts. (RRCGB, DfT, 2017)

Types of Impact

  • Three point belts in cars are highly effective in head on crashes, reducing fatalities amongst belted occupants by 50%.

  • Seatbelts are most effective in reducing fatalities in a rollover accident, in which they reduced the number of deaths by 74%.

  • Seatbelts are least effective in side impacts, with a 10% reduction in fatalities from impacts on the same side as the occupant and a 39% reduction in fatalities in far side impacts among belted occupants compared to unbelted occupants.

Lap Belts v Three Point Belts

  • Lap belts are less effective than three point belts, but nevertheless provide significant levels of protection.

  • In frontal impacts compared to being unrestrained, wearing a lap belt reduces the injury rate by 23% whereas wearing a three point belt reduces the injury rate by 53%.

  • In side impacts, compared to being unrestrained, lap belts reduce the injury rate by 40%, whereas three point belts reduce it by 59%.

  • Lap belts are estimated to be 57% effective in reducing serious injuries in the rear seats of vehicles.

  • Lap belts are estimated to be 32% effective in reducing fatal injuries, compared with when not using a seat belt. Three point belts are estimated to be 44% effective.

  • In side impacts lap belts were found to be 48% effective in reducing fatal injuries. Three point belts were found to be 53% effective in reducing fatal injuries.

  • Both lap belts and lap and shoulder belts are both very effective in reducing fatal injuries in roll-over accidents, by 76% and 77% respectively.

  • A 1999 study found that the fatality rate among people in vehicles fitted with lap belts was higher than those with the three point belt, for all age groups.

Seat Belts fitted to rear seats

  • Analysis of USA road casualty data from the mid 1970s to the mid 1980s estimated that rear seatbelts were 18% effective at preventing fatal injuries.
  • Their effectiveness at reducing the probability of fatal or serious injury appeared to change over time and one study in 1985 estimated the effectiveness at either 60.7% or 53.4% depending on whether the first or last six months of the year were analysed.
  • A 2007 study found that rear seat occupants in a car who wear a seat belt reduce their risk of death in the event of an accident by approximately 60%.

Increasing Seat Belt Use

  • 95% of all car drivers observed in England and Scotland were wearing seatbelts, and the proportion of car occupants wearing seatbelts in the rear of a vehicle remains lower than those wearing seatbelts in the front.

  • For adult drivers and passengers seatbelt use increases with age, and adult males are less likely than females to wear seatbelts for all seating positions.

  • Promoting the positive benefits of seatbelt wearing is likely to be more effective than focusing on the negative risks of not wearing a seatbelt. Non-users need to develop habit-forming strategies to encourage resilient seatbelt wearing behaviour.

  • Highly visible seatbelt law enforcement results in increased perceived risk of being caught and improved seatbelt wearing rates.

  • Seat belt reminder systems fitted in vehicles increase seat belt wearing rates.

  • Date Added: 03 Apr 2012, 08:16 AM
  • Last Update: 12 Jan 2018, 11:22 AM